|
|
| How accurate Part I |
Chuck'in the weight |
Short sheet metal course |
| How accurate Part II |
Keeping it simple |
A good belt keeps you tight |
| When it all goes wrong |
Steel & stuck chuck |
Recovering from the broken tap |
|
Knarled 'Ol Machinist |
This N dat |
Making a rocker |
| Old
bronze & sneaky wizards |
Drills |
Knarling |
| Shop
talk |
Oil
of vitriol |
3vs4 jaws |
| Tubeing rings |
Brass nuts |
Chucking it |
|
Tapering off |
Gett'in da woolies! |
More on chucking it |
| Q.C.
shop project |
Dials and a Barbie cook-out! |
Dialing for zero |
|
Tooling |
Points of interest |
Some quick tips |
|
Threads that run so true |
Keeping the edge |
Re-boring gears & shop tip |
|
More tips |
Tooling around |
Root canal for gears |
|
Parting and getting oiled |
With your clothes on! |
More on boring |
|
Acme screw mak'in |
Don't lose your temper |
Cutting it |
|
Cast iron, dreams, memories |
Runn'n my gator |
Spanners |
|
Facing thin stock |
S'more-lore |
Staying on point |
|
Screw slotting |
Shuck and bump |
Making a tap |
| In
the groove |
Disc facing |
Anchoring a lathe |
|
Internal chuck stop |
Trying to be |
Chucking it |
|
More how toozes |
Scraping II |
Truing chucks & radii benders |
|
Industrial art |
Picture and musings |
Bore reaming |
|
Nitemares overbearings |
More ideas |
Old tricks for old lathes |
| In
a jam session |
New nut-cutter |
Shop notes |
|
When to chuck it |
Lathe benches & tool grinding |
Finishing alum |
|
Cheap shot |
Tooling & visible means of support |
More about tooling |
|
Jig'in it! |
Where to put it |
Threading blind |
|
More shop notes |
Threading, unsticking & polishing tool bits |
Gene's bolt |
|
Tooling |
Drill grinding & the human factor |
Thread & files |
|
More cutting remarks |
Drill sharpening & some oil ideas |
Support and radio |
|
When yer hot yer hot! |
Recycling tools |
Brass nuts |
| The
old grind |
Today's kink |
Old lathes new tooling |
|
Leftovers |
Cutting off |
Face plate work |
|
Quick parting check list |
Fixture |
Tool grinding 101 |
|
Being wary of wavy |
Setting 'tails', a shop story |
Centering tool & knife-making |
|
Tooling around |
Old
age |
Some reaming |
|
Making new lines |
Threading and scraping by |
Some more shop helps |
|
Keeping it on the level |
Steady boy steady |
Getting by |
|
Jack's screws |
Put her in grandma |
Small holes on hard steel |
|
Walk-about tips |
Filing, the conclusion |
|
|
Nutz |
Real axis |
|
| |
| How accurate Part I |
| TODAY'S LESSON: How
accurate do you want it? question: Name the most accurate tool in
your kit besides your brain? tools: lathe or mill piece of round
stock 1" will do by 6" long 0-1" micrometer standard permanent
marker w/ 1/4" tip procedure: Chuck the stock in your lathe or mill,
and take a register cut, in other words, a light cut. Once you have
done that, stop the machine without withdrawing the tool from the
part. Just move it back to where you started. Now measure the piece.
Clean the piece with solvent so it will take a marker. Next turn the
lathe on and mark the piece with a single coating. If in a mill,
simply color the flat work. Now it gets fun. Note where the tool is
in the feed dial, write it down. At this point I want you to take
the marker and wipe a single pass across the clean anvil. 0 the mic
and note the reading (don't worry if you can't get one) then clean
it off. Withdraw the tool from the datum surface. Turn on the machine
and come up close to the piece. The trick here is to remove the ink
without losing metal. If your tool is reasonably sharp you can do
this. Mic it and keep 'diddling with the dial'. Meaning take your
index finger and lightly tap on the cross feed dial of your lathe
VERY lightly. If you are using a mill this will take a little more
finesse because you are having to move the entire table/knee assy.
Let me know what you find out. Ron (880) |
| How accurate Part II |
| By now you have
either completed the set up I outlined and done the tests or paid
someone to fill my van with 10 yards of concrete! In any case,
here's the rest of the story. If you did the mic exercise with the
felt pen, you probably figured out what I'm up to here. With a
micrometer that properly reads '0',a single streak of ink will
measure almost nothing. That's why it is such a good tool to have.
Your eye plays a crucial role in dealing with measurements of less
then .0001. On the lathe as many of you may know, there is such a
thing as 'spring-cut'. This means simply that if you go back over a
previously cut area, the bit will 'relax' against the stock taking
off a bit more metal. The milling machine is no different. This can
work to advantage. The ink works as a register in almost any
situation. You need only to note your mark on the dial, and ink the
part. Some guys will use Dykem layout fluid that has been thinned
out with lacquer-thinner. It dries quicker and leaves a lighter
coating. Now WHEN do you use this? For the most part in finishing
cuts. I will rough something down to the last .010 and switch over
to a finishing cutter. In this way I can have a flatter cut that is
more accurate. If your side cutting on the mill, just pick up a tiny
bit of ink and your at datum. In the event you cannot use a
different cutter, take a small hand stone and give the bit a
dressing on three sides without taking it out. You can do this with
a fly-cutter in the mill. In order to make this work on a mill when
top milling, you may wish to use a dial indicator in concert with
the ink method. Ron (897) |
| When it all goes wrong |
| PART III THREADING;
WHEN IT ALL GOES WRONG OK, it's late at night, your standing before
that cream-puff you paid $700 and a very irritated wife for. The
tool bit has very nicely dug itself into your work, NOW WHAT! Not a
problem. Saving this job is a few steps done slowly and carefully.
1. Don't panic, as you back the tool out of the work, gently turn
the chuck away from you by hand. This keeps you from doing any
further damage. 2.Re-sharpen your tool bit. I will tell you the easy
way to do this in a later article. 3.Inspect the shaft with a hand
lens. It is probably not bent. If it is, take it out of the lathe
and mount it on the wall just over the sign you should have placed
there: TAKE YOUR TIME! 4.Get a 3 corner file and dress the
gouge-site you created. 5. After re-aligning the bit in the holder,
make sure the gear-train is still engaged with the spindle. Now go
to the middle of your work with the bit and close the half-nuts
where where you have been cutting on the dial. Your doing this
manually of course. Just move carriage back and forth until you find
your 'sweet-spot' again. 6.Now for the magic. Bring the bit in near
the cut. Then using both dials, maneuver the tool until your back in
the cut. When you get it close enough, back out the lash on both
dials and set your tool a bit closer to the work, but not touching.
7.Now for the lump-in-throat move...yer gonna love this! Take the
tool and re-position it at the beginning of the cut. That is, just
off the end of the part. Start the lathe and engage the chasing dial
on the sweet-spot. Your tool is not near the cut of course, we're
still working on final positioning here. After the bit crosses over
the end of the part, turn off the lathe and see where your tool
actually is. You will see it is still a wee bit off the mark. Using
the a fore mentioned method, fine-tune this now. Remember to set
both dials at 0. This way you know where the hell you are when you
re-cut. Now go back to the end, start the lathe, engage the dial. As
the tool moves along the piece, slowly crank the CROSS-FEED dial
into the cut until it just touches the work. It will shave a bit of
metal. As your doing this, note the real position of the cross-feed
dial. Remember this reading. When you go back to take another cut,
set it on the reading and re-zero. You are now 'back on track'. Take
spring cuts, about 4 will do. Thus assuring you have cleaned all the
junk out of the groove. 8. When you have done this either check the
piece with a nut or finish cutting. A finishing die is sometimes
helpful in some situations. It should only be used when the finish
does not have to be all that accurate. 9.To finish your thread, get
a mill-smooth file and lightly go over the top of the threads. This
will put a small flat on the thread. This also relieves it for a bit
of Clarence in the root of the thread. If you have a 3-corner file
or a piece of wood with a V-form on its edge, get some 400 grit wet
or dry paper, clean the chip from the work, and apply some Kero to
it with an acid brush. Now go over your little gem with the
thread-hone you just made. 10. Another way is to get a nut the same
pitch as your work, cut it in half, and use this with some clover
valve-grinding compound to finish. Keep in mind you want this thing
to fit as snug as you wish as well as look good. IN GENERAL; There
is a lot more that can be said for threading. I have only given you
a few pointers here. The only way you can do this simple task well
is to practice it, and keep notes. Ron (1083) |
| Knarled 'Ol
Machinist |
| An operation of
this type really puts your creme-puff on PMS. Punishing MY
SouthBend! I'd do this with some sort of 'clam-shell' type of rig.
On hand-screw machines we use a tool attached to the top or side of
the lathe. It can also be bought along with a quick-change tooling
system. Hmmm...I'm not really doing this justice here, so let me
start again. Knarling is in my humble opinion THE WORST THING YOU
CAN DO WITH YOUR LATHE! Your taking a PRESSING tool and jamming it
against those 'not so young' castings and bearings. In the words of
an MSC instruction sheet, "In order to get a real good imprint you
must (GULP!) jam the tool against the work". Call me a sissy if you
want but I'd rather eat babbitt bearings before I'd do this to my
lathe. Instead get this hear unit that works like a clamp and exerts
it's own pressure while putt'in wrinkles on your work. When that
lathe was young, you probably could do this on a lathe. But it
really will put a strain on everything involved. If you must, buy an
old junker with a worn-out everything and rig IT to do yer
dirty-work! OK 'Nuff of that! Today's shop-tip is simple: Look at a
decimal equivalent chart. If you will note half of an inch is .5
Half of that is .25. If you want half of 21/32 it will be 21/64. How
did I get this? Simple. Every time you look for half of any fraction
on the chart; merely drop the denominator down to the next level.
Hence: 1/2,1/4,1/8,1/16, and so on. Half of 31/32 is 31/64ths. Got
that? GOOD! Put a gold star next to yer name; but put a little green
around it so's the rest of the class thinks you been around!! Ron
(1142) |
| Old bronze
sneaky wizards |
| I agree that bronze
seems to be relegated to the cheap seats in our modern culture. The
cheapness of off-name brands gives the buyer the impression that if
it don't have ball bearings, it's no good. Before 1920, almost any
bearing was a bush of some kind. And some of these weren't even
metal. Steam ships were using lignum vitae bearings. This stuff is
harder then a tarts heart and very oily. Also very dense. For heavy
loads where they could receive some attention, they made excellent
bearings. When the locomotive came along they had a big problem with
having all those truck-bearings needing oil. Babbitt was the choice
of material for it's good resistance to poor conditions like rain
and dirt. As a lad,I remember watching trains in my town going by
with truck fires! Machinists at the shed were always busy pouring
truck-bearings. For a long time babbitt was used for the mains in
almost every auto. When re-building my 289 ford engine in 1976, my
replacement mains were still babbitt. And the bearings I bored for
the engines on the Mt. Washington Cog RR were bronze. Those were a
large casting weighing in at 60 lbs. They had to be bored in the
1920 Prentis Lathe. The overhead belt system driving that was
powered by a water-turbine that had lignum bearings. In summing up,
I think there are two ideas that go into any well designed project:
1. Every detail must always be a 'strength move'. You want to build
that sucker once. 2. Careful selection of materials along with good
design will always result in a classy piece of work. If you know
what a material can do then you know where it can be applied. 3. Oh
and rule 3 Old age and treachery will always over youth and skill,
(watch out for old machinists, their sneaky wizards!) Ron (1171) |
| Shop talk |
| I would think South
Bend would at least drill for a lug to keep that split-bearing in
place. No matter how well machined a sleeve-bearing is, once it is
installed, it will seat itself in relation to the location of its
'running axis' and the strains that go with tool force and belt
ware. As for cast iron bearings, this is probably the only
iron-to-steel bearing I can think of. The reason cast iron is so
good is because of the carbon laced through it. In volume one of
Chapman's book "WORKSHOP TECHNOLOGY" the author explains how cast
iron can slide easier then steel due to the graphite flakes that are
smelted into the metal. As long as you keep some kind of lube on it,
it should last a long time. My only other comment on boring out a
casting would be that it may tend to weaken the head stock integrity
sacrificing strength for accuracy. Both are very important. Tim Q,
anytime you can kick the tires on a deal prior to buying it is a big
plus. Looking over the owner can be as revealing as a hairline crack
in the bed! I would think that a $300 cost difference for a
home-town deal is worth it if you can actually put your hands on the
goods, (and on a throat should that creme-puff buy the farm before
it gets out of the yard!) Shake it, twitch it, tweak it, buy it.
Your description of it sounds good to me. Ron (1182) |
| Tubeing rings |
| The problems of
cutting thin-walled tubing are these: 1. Support without
de-formation 2.Facing the cut end 3.Tearing, the tool grips the tube
and rips it out of the chuck. IF your only doing a piece or 2, first
grind a parting tool no more then .062 wide with a 3 degree
clearance angle throughout. Find a piece of metal that is close to
the ID of your tube. Slide the tube over this and chuck. Expose
enough tube for parting off. With the lathe in reverse, and the tool
up-side down, use a slow speed and lots of oil. Then take a piece of
pipe that can be bored and split to make a 'pot-chuck'. The fixture
is bored enough to leave the part exposed enough to be faced. This
is a very accurate operation. The fixture can be re-used for this or
another job. IF you want to make over a dozen pieces, get a piece of
steel bar stock and center-drill it. Slide the stock over this
leaving an inch of bar stick out. Engage the tailstock-center in the
bar end. The bar inside the tube is now chucked. Turn your pieces as
described before using a home made gage to re-set the tool each
time. As you work down the shaft keep your pieces away from the
current parting off site. Use the pot chuck as before to finish. You
can use a 1or 2" travel-dial to part off your rings. And a small
file to de-burr the corners. Ron (1296) |
| Tapering off |
| I have never had
much time on taper attachments. Most of the time I use the compound
and fine tune it with scrap and a little trial and error. For long
tapers though the tool you describe can do accurate work when set
properly. First carefully check your TPF in the book. If you still
have trouble with it, start by using a hand lens for re-setting.
Trail and error can be very accurate. Check your taper using a
micrometer. You will have to check one inch of cut and transpose
your taper per foot. And see if you can find or make a plug-gage.
Here are some useful formulas: 1.To find taper per inch divide the
taper per foot by 12 2. To get taper per foot subtract small dia.
from large; divide by length of taper, and multiply quotient by 12.
Having said all that there is a third way to figure this out. If the
taper is no longer then the total screw-length of your compound; you
may set it precisely using a sine bar and a scrap piece of 1" round
stock. Look up the sine for the degree of angle your looking for in
your Machinery's Handbook or other reference. The figure given is
the length of plug you'll need times the length of your sine bar
Example : With a 10" sine bar, what must be the difference between
the heights of the 2 plugs for an angle of 18 degrees? solution: The
sine of 18 degrees is .309. The difference in height= 10X.309=3.09"
So you carefully face both ends of your plug gage keeping the tol. @
+/- .002 Place a good piece of round stock in the lathe with a
center in the tailstock. Check the axis of the bar with a dial
indicator to insure it is parallel. Now place the sine bar and plug
against the compound and bar. This may require a parallel and a
means of holding all this together. Ideally your compound will have
a milled side where you can line all this up. You may have to stack
some stock up in which to lay the sine bar assembly on. However,
once you have this all set, you will get a very accurate angle cut.
Be sure to have your tool on center. Write the set-up in your shop
journal and keep any jig parts from the job in a labeled box. Ron
(1337) |
| Q.C. shop
project |
| For the more
intrepid home-shop machinist there is the alternative DIY QC tooling
system. A few months back my friend and partner needed a
quick-change system for his Smithy. We had the great fortune to have
an old plunger-type tool post but no holders. I bought the correct
dove-tail cutter and a 4 lip cobalt 1/2" end mill ($25) and went to
work. Having both a vertical mill and a horiz/vert. band saw is a
great advantage. This was also a great beginners project for the
mill. We used hot rolled steel and after grinding off the skin,
fly-cut all surfaces. Tim (my partner and student) then painted
everything with layout dye and using the surface gage, laid-out all
the blocks. He used the band saw to rough out all the slots and
d-tails. Thus saving time and expense on my cutters. When it came
time to bore for the bar-holder, he finished milling the dove-tails
on it, squared it with an indicator, and line-bored it while it was
held in the tool-post. We made 3 tool bit holders, 1 boring bar, 1
knarling tool,1,cut-off tool, and 1 blank. After lapping off all
tool marks I finished the holders by heating them on the kitchen
stove until they turned a nice purple. You can also drop them into a
1 gallon bucket of 10W-30 motor oil for a black oxide finish. This
is a great project for anyone who likes to fool around in the shop.
In our case, we could not afford to buy $300 worth of tooling from
M.S.C. (I will NOT deal with Horror Fright!) . This same project can
also be done on a shaper, drill press, and band saw. Ron (1473) |
| Tooling |
| Just catching up on
some of my reply work here. One of the members mentioned using the
old style tool-holders for his lathe work. In some cases I can see
where this can be a good idea. For example. If your working the end
of a long shaft using a steady-rest and you are really tight for
enough room, use this tool. If it is an old tool-holder chances are
it was drop-forged and very tough. Just the thing for having to
extend way past the usual overhang. Just remember when you do this
to TAKE LIGHT CUTS!! Another time to use this occurred to me just
last week. And I just now thought to use it DUHH! I was having to
turn a 7.5"X3.5 piece of alum round stock. Holding it with a piece
of 1/2" CRS threaded into the blank. After very carefully
center-drilling for the live cntr. I had a whole lot of no room in
which to skin the OD. down to size. The alum blank extended below
the saddle. So I had to use a boring-bar to turn the OD. I have an
Aloris system that came with the lathe, (SB heavy 10 w/bells and a
shiny whistle!). In this case I used my boring-bar holder that has a
1" hole in the block. I turned the insert around and did the cut.
Now had I used the left-hand tool holder, I may have been able to
take a larger cut. It ain't the machine what make it work, it be da
man runn'in it! Ron (1514) |
| Threads that
run so true |
| Paul and All, First
I'd ask you if the nose on that dividing head is soft enough to turn
down. Then I'd say no if it were. Rule number one in machine shop,
(after never believe your own bull-$**T!) ANY TIME YOU DESIGN
SOMETHING, IT MUST BE A STRENGTH MOVE! In this case I'd say make an
adapter AKA gazunta, (dis gazunta dat!). BUT you got a real good
idea there. Especially if you can use a 4-jaw chuck instead of a
3-jaw. This way you can do stuff like offset dividing head milling,
cams, almost anything really. A SHORT TREATISE IN INTERNAL THREADING
SIMPLIFIED. 1. Bore hole to OD of thread, +/- .003 2. Set compound
over to the LEFT of 0 so it's pointing to a 1:00PM position of 30
degrees. 3.Place spindle in BACK-GEAR. 4.Grind boring/threading tool
to 60 degree V. Use fishtail to check tool form. 5. Set
boring/threading bar with fishtail so it is against the part. Tool
must be square to axis of part. Also be sure tool is on or a bit
above center to hole. 6. Remember to bore out ditch at end of bore.
You have to have a place to stop! 7. Set Q/C gearing or change gears
to suit TPI. 8.If you don't have a 1" travel dial to stop with, put
layout dye on your boring bar. When dry, scribe mark on bar so you
know when to stop cut. If you do have a dial, set it so it will
register .1, this way you can see the end coming. (In this day and
age it might not be a bad idea, LOL!) 9. Time to practice. This is
where your undies may tend to disappear! You must do to things at
once. Stop the feed while taking the tool out of the cut by running
the cross-feed IN. Do this with a piece of PINE. Bore a piece of 2X4
or other SOFT wood. Go through the motions as though it were the
real thing. When you come to the hash-mark or dial spot stop the
feed by lifting the handle AND dialing in the cross-feed toward the
center at the same time. You only need to dial in about half to 3/4
of a turn to clear the thread. Be sure you do not crash into the
opposite side...to often. 10. Now that you found yer undies, (they
were there all the time!) set both dials on zero. Do this by
starting the machine and dial in until you just touch the wall. Now
set to 0. 11. From now on, you will only advance the compound to
feed in the cut. The cross-feed will ALWAYS come back to 0! 12.
Advance the compound no more then .005 at a time. Remember, since
your 'inside' you are cranking the tool 'out' so to speak. That is,
advancing it towards you. 13. Every 2ond cut, do a spring cut. This
is where you reset the cross feed without moving the compound. The
tool then tends to relax against the wall. 14. When you get close to
finishing, set the cross feed .005 beyond the 0 mark. This will
allow the tool to cut on both sides of the thread. Then go back for
3 spring cuts. IN GENERAL, it is pretty simple to do if you TAKE
YOUR TIME!! With some jobs you can finish the hole with a tap. Kinda
like reaming. ALWAYS USE A PLUG GAGE TO CHECK YOUR PROGRESS. Make
one if need be. Ron (1564) |
| More tips |
| Back in 1977 I did
an adult ed. nite class in machine shop at the local Tech. school. A
typical south Fla. mix of red necks, P W engineers, off-shore
beginners, quite the lot. You had to get past the Ron Test before
laying hands on so much as a twist drill. How many thousandths are
there in an inch? Where are your safety glasses? Your answer was
rewarded by either a blue print and a piece of 1" bar stock; or a
dull file, square, and block of steel you had to square fit to the
frame. With one exception, every Pratt engineer flunked the test.
The one that passed was a (believe this!) little blond girl fresh
out of Georgia Tec. Engineers are great with figures and can come up
with more ideas then a dress designer for Victoria's Secret. Trouble
is the machinist (and the poor model) end up putting things in
un-natural places. One guy came up to me once and said the drill he
was using was obviously dull and soft 'cause it would cut his piece
of alum. It was a 1/2" left-handed drill. Before I leave for the
shop here is another view on your glib gib thread. Take off the
cross-feed casting and examine it. With a clean straight-edge or
parallel check the mating parts for wear. Most engine lathes will
have some 'saddle'. Hi spot both pieces with a blue wide marker and
lightly go over both pieces with a new single-cut mill file. Just
enough to get a nice gray appearance over most of the casting. You
just want to level things a bit. Now do the same with the gib and
re-assemble. Don't forget to oil the ways again. This should improve
things a bit. Many old-timers will use the first screw on the gib to
do tolerance OD work. They will tighten this screw a bit so they can
have a firmer feel when finishing a shaft or single-point thread. Be
sure to loosen it back up when your done. Another old fart trick is
to grab the tool-post with one hand and pull the lash out of it.
Shuck Jive machining I call it. Ron (1611) |
| Parting and
getting oiled |
| Some general
comments: PARTING OFF If we examine the reasons behind sickening
crunch, it can be avoided. First spring. Energy building up and just
waiting to perform, usually at a time of its choosing NOT yours. If
you can make this work FOR you. The goose-neck parting tool uses
this philosophy. So does the inverted tool. It springs AWAY from
certain crunch. second: Dust. While the goose is springing it
creates dust and small chips. This swarf, (love that term!) does a
real good job at welding itself to anything not well-oiled. It pays
to be well-oiled. (umm, naaw, I'll leave that one alone!) third:
Sharp. I'd use a PT what got a sharp edge of 5 degrees from the
horiz. Stone the edge with a fine India. (These are my favorite
stones) Take off the rough grind at the very edge. Moron this later.
forth: Tight. Floppy bearings, loose carriage, loose cross-feed, all
contribute to sharp pains in re-cycling outlets. fifth: Keeping it
close to home: Keep the bit just slightly over an inch beyond the
holder. That is providing your lathe is in the 10" range. If
smaller, keep it shorter. Now back to sharpening for a minute. The
edge of a tool looks like the Specific coastline under a microscope.
Lots of juts and gully's, very irregular. The points break off and
the gully's fill in. What nature is trying to do is create a level
playing field. Let's accommodate Her. If you have a surface grinder
us a white wheel that you just dressed. FLAT grind all your angles.
No angle should be more then 5 degrees. Unless your cutting plastic
or wood. Then go back and use a very fine Arkansas stone to polish
up the faces. Break the outside leading corner into a small radius.
Even if you are going for a square shoulder, there is NO good reason
to leave a sharp corner. It is a great place for a shear-failure. If
you do not have a surface grinder a fine sil/con #150 grit will do.
When you put this wheel on your bench grinder, be sure it is used
for finish tool-grinding ONLY. Do NOT use it for lawn mower blades
and other 'fine work'! Keep it dressed for sharpness and balance.
Then go out and buy a diamond hone for about $!0. Hone 90 degrees to
the grind. Use a magic-marker to hi-spot your progress. Take off all
the grind marks about 1/16" back from the edge. Kinda like jointing
the edge of a plane-iron. Hmmm, this is turning into a class on tool
sharpening. If you don't mind, I'll quit here and do a more in-depth
article on sharpening. keep 'em flying, Ron (1624) |
| Acme screw
mak'in |
| ACME THREADING FOR
THE INTREPID! THE acme thread has the wonderful form of your typical
Aztec ziggurat. It is both strong and accurate. Making one on the
lathe is really quite simple. 1.GRINDING THE TOOL: You can use
either a regular tool bit or a cut-off tool. I like the parting tool
because it has a lot of meat under the cutting tip. In any case use
your protractor set to 14.5 degrees. It is a good idea to have a
full-size drawing or a sample piece of the thread you want to make
handy. Then grind both tools (that is if you intend ID threads as
well.) Grind the TOP angle. About 3 degrees to give you a bit of
rake. Then finish this with a fine hand stone so you have a bright
edge. Now do the front (15 degrees) keeping it square with the side.
Polish this to. Bring in both sides at the same time. It's a good
idea to use the tool rest set at a 5 degree angle. Once you have all
that done, clear the bottom of the tool so it won't rub on your
work. 2. SETTING UP: In reading my shop reference circa 1943,(my
dads book of course!) it says the following, "Drill a small hole at
the end of the cut so the tool has a place to safely rest." So if
your doing a thread with a root form of 1/4" drill the hole .250
This should give you .125 in which to stop...YEAH RIGHT! You will
lose 5 pairs of undies doing this! Instead just put a mark on the
shaft and pull out as best you can. Ummm where was we? Ahhh yes,
time to set the compound 14.5 degrees so that it points to your oil
can on the shelf above your lathe. No shelf over lathe? Shame on
you! Stop and build shelf being careful to place oil can on the left
side of the shelf. REMEMBER, advancement of tool is always in the
direction of thread. A right-hand acme thread will be pointed to an
11:00 position (more or less). Square to the chuck, and a tiny bit
under center-line. Select thread and gear set-up and place lathe in
back-gear. 3. RUNNING THE JOB: Cut your threads as you would any
other job. Take a clean-up cut on every other pass. Have a gage to
check your progress. Use the direct dial feed method when your close
finishing. You want a rub fit, so polish to finish dimension if
possible. Ron (1636) |
| Cast iron,
dreams, memories |
| I always love
working cast iron. One of my favorite metals. In Chapman's book
"Workshop Technology Part One", he describes a condition called
'chilled iron' This is a surface condition that results in the
molten metal hitting a cool or cold sand wall in the form, (cope).
It can be an accident that the sand is cold, or intentional. When
this does occur the result is a CI surface that is very hard. It can
be used to advantage when designing machine-castings where an area
that normally wears quickly is now hard. The effect is only 1/32" or
deeper into the casting. As for dealing with the chips, I use no oil
at all. There is enough carbon in the CI to skip any need for oil. I
clean up with a magnate and put the chips in my garden! My turnips
have tired blood! Cast iron has to be one of the best things to
happen since sliced bread and Viagra. They both require less effort
to operate! AHEM...anyway this is really marvelous stuff. The
average machinist can fire his own cupola furnace and pour his own
castings. Bury them in the back yard to season them for a year or
so. Then dig them up and have some rough castings that are better
then what can be had on the market today. Years ago the major
foundry's use to pour for the big 3 car makers. They would pour 'the
right stuff' into the old cupola, let her cook, and tap off molten
iron that would end up as engine blocks. These in turn would get
buried in a Detroit backyard to season. This allows the metal to
gripe and complain in a slow fashion letting its latent issues be
heard...and ignored by the local worms. After a few years, they get
dug up, and become the 1956 t-bird, or '57 Chevy' 283, (Dems were da
daze!) engines we all still salivate and dream of. OK so I'm off
topic, give an old fart some slack here! Anyway you can do many
things with this very old and venerated metal. Like so many of the
ethics and wisdom that has been cast aside; it just sits there
waiting to be re-discovered. Ron (1728) |
| Facing thin
stock |
| G'Day! Here is a
common problem most of us find more often then we think, Facing
short pieces in the lathe. Seems almost impossible. Even if you have
1 side faced. Pieces 1" wide and 1/4" thick can be a real pain to
face both sides of. MSC sells a magnetic booster that allows you to
place whatever you want against its face. But it is very expensive,
like $180 yeeoww! I have been doing a lot of thin wafer facing
lately in making an industrial-grade stone grinder. I will outline a
quick and a more involved jig for quickly centering this kind of
work in any lathe. QUICK AND SIMPLE This is what I call the
cheap-shot. Get 2 parallels the same width. These must be 1/8 to 1/4
of an inch SHORTER then the total length of the jaw. In some cases
you may have to mill a dedicated set of these just for the lathe.
Hot-rolled steel is perfect for this 1/4 to 1/2 inch thick. When you
set up the work, start by placing a short 1/2" rod in the
tail-stock. Then set the work-piece lightly in the end of the jaws.
Rotate the 3-jaw chuck (or 4-jaw) so that the 2 bottom jaws are
horiz. Place a parallel on these. Now take the second parallel and
slide this in place on the top jaw. This is a bit of a juggling act!
Hold both parallel and work-piece while bringing the tail-stock up
to snug. Having fun yet!? By now you see where I'm going with this.
The parallels line the part up with the back of the chuck using the
tail-stock to hold it in place while you tap and tighten. This way
will work. It is fairly accurate and requires almost no machining.
It's also a pain in the a$$ and can leave marks on the finish of
your work. SOOO, here's the alternative. Make a daisy parallel
having a stem and 3 'petal's. Simply put you make this out of some
bar stock 1/2" by how wide you need it; and screw the 3 pieces to a
piece of pipe that has been skinned to slip-fit into the bore. The
short parallels will be fitted on to the pipe by forming one end on
the bench grinder. A hole is tapped to accept a 10-32X1/2" deep
socket-head screw. To install the screws, just drill 3 holes all the
way through both sides of the pipe. They don't have to be exact. As
long as you lay out the holes as long as the bars have their holes
the same distance from the end of the pipe. I use my 3-jaw chuck as
a dividing head for this. The bars have to be machined on both sides
before drilling. You can put all 3 in a four-jaw chuck and finish
them to final width.. Now screw the jig together sliding the whole
thing into the chuck. Check for fit making sure all 3 bars are in
contact with the front of he chuck. Now you will still tap your
work-piece to seat it against the jig. The whole idea is to have the
workpiece snug against the 3 bars which in turn will be sung against
the face of the chuck. Should the parallels loosen from the pipe, no
worries. The pipe is only a 'keeper' holding the bars from flying
out during machining. I plan to try this out very soon. Anyone else
feeling brave? Ron (1729) |
| Screw slotting |
| For small screws I
always used a jewelers fret saw with the right thickness blade. You
should have one of these with a good selection of blades. They do
real nice work when small and neat counts. Ron (1731) |
| In the groove
|
| My first choice of
file brand is Nicholson made in USA followed by Swiss Pattern Grobet.
I will go out and buy dull Nicholson files and use them for scrapers
and knives. When I go to a flea market, I will drop-test an import
prior to purchasing. If it don't break then at least the steel may
be worth it. Now to re-state my way of file-cleaning. It doesn't
matter if you roll the brass cleaner toward or away from you so much
as you press down on the tool while scrubbing along the groove. This
produces grooves in the end of the brass pipe. As the brass is
pushed along the grooves it displaces the metal and crud with some
of itself. The reason I use a rolling motion is to keep from missing
a part of the file. Start at the base of the file. Scrub back and
forth. Going down first 1 side, then turning it over and cleaning
side 2.It is not important to keep the cleaner in the same grooves.
Pressing and scrubbing is more important. Dull files can be
re-sharpened by brushing on Navel Jelly. Let her cook over nite if
it's in really bad shape. After washing off the acid with plenty of
water, oil it. Then when your ready to use it, clean off the oil,
and begin to cut. My own take on preserving a finish from rust. I
take a cue from the old ways. Using a modern substance. Dykem spray
layout dye. This is a light 'paint' that comes off with common
lacquer thinner. If you wipe all the painted surfaces with common
10W30 motor oil; wipe the bright areas with lacquer-thinner. Then
paint or spray on the Dykem. The oil on paint will keep any dye from
sticking. So much for method 1. method 2: Every piece of new
equipment I ever mill-righted had 1 thing in common. They all had
lots of grease all over the brite-work. Before storing your
equipment, clean it very well, oil the hell out of anything that
moves, and grease the rest. This should keep things manageable.
Before draping a single piece of heavy-weight clear plastic over the
machine, place either a pan of moth-balls or this stuff they use
with house-plants that soaks up moisture like a sponge. Bostick Rust
inhibitor spray leaves a waxy film that is easy to remove. There is
also this silica pellet stuff used for indoor plants. It soaks up
moisture like a sponge. Grease however is the cheap way out. If you
miss getting it all off, future oiling's of the machine will
dissolve it. Ron (1848) |
| Internal chuck
stop |
| Dave, Sounds like
what I just finished doing. The back-stop has a turned slip fit into
the bore. A draw-bar holds it snug against the chuck face. I milled
out slots just wide enough to admit the chuck jaws. I left about
.003 clearance for the jaws to slide freely. My design relies on the
draw-bar holding the stop firmly against the chuck face. In this
manner, the stop stays parallel to the chuck face. In use, the tool
allows me to do most short slug and tube work. Allowing me to do
acceptable face and bore work. It took time to mill out those slots
for the jaws. Since all I had was a shop made 30 degree wedge to
line up each slot with. I finished the slots with a medium India
stone and diesel. It's still possible to do close work using simple
well-made tools. Ron (1867) |
| More how
toozes |
| Staying in shape
means you don't have to diet. The same goes for keeping in trim
around your lathe. Using the dial indicator and your brain is always
a plus. The little gadget you mentioned probably will do the job. It
is a matter of spending some cash for a rig you hardly use or spend
it on a better indicator that you can use for everything. As for the
Jez-us mark, it will probably move around a bit regardless of how
well you '0' it. The wear in the bed alone will cause it to travel a
bit. However if you want to try and keep it in alignment with the
head stock, mark the facing side of the bed using a center punch and
us this mark to position your tailstock. Now when it's time to 0 the
't'-stock you have a place in which to do it. I would have a dead
center that you buy for the express porpoise of aligning the
tail-stock. Keep it in it's own box. And for today's shop tip: Very
often, the compound is ignored by the operator unless he wants to
turn a chamfer, or short taper. It can however help greatly in
finishing a diameter. Set the compound at a 45 degree angle. Put
your indicator in the tool-post. Let the indicator come in contact
with a bar you have chucked. After zeroing it, move the compound and
note where the dials are in relation to each other. Since the
compound is at the half-way point between 0-90 degrees, you should
see a movement of approx. 1/2 the distance of your cross-feed dial.
If you keep a wall chart you can hang on a wall near your lathe, you
can then add these little cheap-shots to your ever-expanding
knowledge of how toozes. Ron (1885) |
| Industrial art |
| And if you want to
get even closer use a magic marker on the datem surface followed by
your .001 shim stock. When you see you are polishing the ink, your
close! When I have a lot of parts to do I will often mark my cross
feed casting with layout dye. This flat surface lined with
hash-marks tells me when I am getting close to my dial position.
Back when I was doing prototype work, I would decorate my lathe with
markers. A strip of masking tape on the top of my cross-feed
dovetails that had different colored lines. Each line would
correspond with a dial mark of the same color. This way, I could
keep track of many diameters, ditches, or bores. Ron(1897) |
| I have used a trick
close to that for doing production work on a manual lathe. I will
mark the cross slide dial with a pen mark off to one side or the
other of the factory mark and then color code that mark with one on
the knob. Align the marks with the right color and I was able to
maintain accuracy of +/- .003 on over 500 parts. I also did the same
thing with the carriage hand wheel but it took a bit longer the get
the marks in the right place. Gerald (1898) |
| Nitemares
overbearings |
This is the part
where I get to show what I don't know about lubrication. Let's start
with what you don't know: 1.What is really in your oil cups besides
oil, souvenirs from Dessert Storm maybe? 2.Moby Dick oil, (NOT PC,
I'll pay for that one!)? 3.Several layers of varnish? 4. All of the
above working merrily together Gnashing huge grooves in your bronze
witch will be exhibit A at your trial of LURCH VS USA (Us Southbend
Amateurs), you will be found guilty of being over-bearing neglect,
your wife will divorce you, your children sold to cover court-costs,
and you ,you miserable wretch of a machinist will spend the rest of
your life selling pot-metal made in China torque-wrenches at a south
Florida Flea Market!!!! .....but I'm feeling much better just now G
OK, here's the deal. When you decide to clean out those bearings by
adding a detergent you will loosen a certain amount of crud; just as
you would if you did the same to an old car engine. It may contain
some stuff that could give you the above nightmare. Most small
lathes have provisions to keep contaminants out of the bearings. But
I don't know if they have any way of flushing them out, short of
disassembly. You could start by using a thin 10wt oil that you
pre-heat prior to adding to the bearing cups. Very warm to the touch
say. Then, after cleaning the area around the seepage, collect the
oil in a clear glass container and look for any sludge. Do this
without running the lathe. You may have to loosen the caps to allow
for a free flow. Id do this until the oil runs clean. Then re-adjust
the caps, and add new oil. I'm shooting from the hip here so if
anyone has some real info from the company, I could use it to clean
my bearings. The above is probably the easiest way short of dis-assembly
to deal with the problem. It may only make you sleep better at nite...
as you dream about that flea market. Ron
(1924) |
| In a jam
session |
| Lew, Your worrying
about to much. A jam nut on the end of a pedestal grinder is just a
'keeper'. If the nut is acting like a French Impressionist, (Too
loose La Trek) just put some Loc-tite on the threads. To obtain a
better running grinder, try getting some hole-saw slugs from a
welding shop. Say 2-3 inch. Bore and face 2 sets; one for each
wheel. These dampers should be no less then 3/16" thick. Assemble
everything with a small amount of aquarium sealer. This should keep
things from achieving escape velocity. But your problem makes for
good discussion. I recently had a similar problem building a grinder
from scratch. This one has a 30"X3/4" shaft that has no less then 6
wheels on it. I had to make everything but the bearings;shaft,3-step
pulleys, dampers, spacer collars. It has L/R fine threads on each
end. It was pretty easy since I was using 2 nuts, I had on hand. One
way to get around the problem of matching a thread exactly is to
start by making a go/no-go master. Start by making the master
setting-ring that is split on one side and is tapped so it can be
set. The internal threads carefully finished with a piece of pine
dowel dipped in 200 grit/oil honing compound. This is screwed into
the setting-ring until you have a nice finish to it. knurl the o.d.
prior to parting-off. You then set your gage by screwing it on the
existing shaft. Leave it a tiny bit loose so your nut will be a bit
snug. The plug-gage is similar to the go/no-go gages you see in tool
catalogs. Just make the plug so that one end is bigger then the
other. What lies in between will be what you want. When faced with
the eternal problem of HOW TIGHT DO I MAKE THIS TURKEY!! -Start by
asking yourself what your really after -consider 'the 3-pass
method'. Two roughing passes, one finishing pass, then file yer tail
feathers off! Hey we all do it including me! -put a starter dia.
ahead of any shaft you wish to press. IOW turn the end down to start
a press fit. -any shaft can grow.010 by knurling it. Did I confuse
you yet? Ron (2009) |
| When to chuck
it |
| Lurch, Don't go in
there, there's a monster in there! You have touched on the main
reason scroll chucks can be a royal pain in the piles. Ummm, that's
not exactly how I wanted that to come out.. OK let's try this again.
THE SCROLL CHUCK. Wonderful invention. It turns, it slices, it
dices. It gets worn in the same place no matter who owns it. The jaw
end and the scroll always wear because this is the most versatile
chuck for holding anything round. And they are pricey little toys to
make. The 4-jaw is cheaper to buy and even more versatile. Not
helping yet? What's to do! 1.Buy a new chuck and get that second
mortgage on your soul you always wanted! 2.Live with it, no ones
perfect 3.Put it on the shelf and start using your 4-jaw and a dial
indicator. 4.All of the above. And don't forget your lithium. If you
start by checking the jaws for wear, place a hardened and ground pin
at the back of your chuck. Then take an indicator and 'map-out' your
jaws. The pin will take out lash wear. Go front to back on each jaw,
then carefully check the concentricity of your jaws. After finding
out what you already knew, you have some choices to make. Here we go
again!! 1. You could get new jaws from the company that have
detachable ends or better yet go out and buy soft-jaws, bore them
true and never take them off. 2. Chuck a 2" piece of round stock
1/4"thick in the back of the jaws and ID grind them. Then carefully
back-grind the lip you left. 3. (Oh, your gonna love THIS one!) Make
jaw inserts held in place by a set-screw. Install these and bore as
soft-jaws. Or just put up with it like the rest of us. Use a 4-jaw
for close work and ignore old-fart machinists on Halloween!!
regards, Ron...now where did I put my broom?? (2028) |
| Cheap shot |
| Good 'ol Kero will
do for plastics. Thread-cutting oil can be had from Texaco through
MSC. A gallon of it is about $20. I mix it 50/50 While I'm on the
subject here's today's cheap shot. Parting usually sux. The first
thing that happens is your undies disappear..er, to the usual place.
Next comes that sickening crunch Now you remember that your shrink
said to get a hobby that is RELAXING!! So, get a coffee can and some
1/4" copper tubing. A brass valve that fits the tube and some RTV.
You are making a swing-away oil drip can. Fashion the arm what holds
the can. Be sure it is not in your face by making sure it stays in
the middle of the lathe and behind the far way. Drill and tap the
can for the valve and fill the can with about an inch of oil. NOT
SOLUBLE!!! OIL! Use something cheap and superficial 10W30. I say
this because there is always some over-achieving "closer tolerance
then-thou" WW who will buy oil that cost a fortune and cannot be
recovered. Besides, the cut-off oil will lube your machine. To use,
let it do a moderate drip as your sinning bravely. Drip-pan, apron,
and long string tied to yer undies. Trust me it'll work. The string
I mean. Ummm, so will the oil. You can reclaim it using a piece of
alum screen and a cheap paper-towel in the bottom of the can. Hey
would I lie? Seriously though the big problem with cutting off is
first welding, then galling, then snap ,crackle, and crunch. The oil
keeps Charles De Gall from helping you. Now that the state of Quebec
has a hit out for my prize quiche, I'll slink on out of here. Ron
(2052) |
| Jig'in it! |
| The beauty of any
Q/C tooling is in the ability of doing just that. But it doesn't
stop there. Here's some more how tuze: -Check to see if you got the
right T/P package by taking a holder and adjust it so the nut is
centered on the stud. This places the holder in the middle of its
adjustment. Now put this on your tool post. If it's way above or way
below with a 3/8 tool bit in it then we need to go over the
procedure of increasing or reducing the height. -Depending on what
you have for tool holders, you can mount just about anything on your
tool post: A. The 1" boring bar holder will accommodate a Foredom
Hand-piece. You now own a very small ID grinder! B. Get a machinist
clamp and a piece of 1/2 plate 4X6 inches. Square the plate and
tighten against the face plate so the tool holder is square to the
head-stock. Now put the sanding disc you made to fit the lathe in
the chuck*. Instant precision sanding machine. C. Make a small block
that you can put your indicator in. Now put this in your tool
holder. There's more but my wife is standing in the door-way with a
pitch fork so I get the feeling that: 1.forgot her birthday 2.she
found that pink garter under the front seat of the van 3.SWMBO want
help covering the strawberry beds with hay and my corpse! later! Ron
(2071) |
| More shop
notes |
| Try these on for
size 1. For you folks with QC tooling, make a drill stabilizer that
fit into your tool-holder. It's really just a piece of steel with a
'V' in the end facing toward the front (back?). When using long
drills, center this little baby next to your drill point while
feeding the drill into the stock. It will keep the drill from
wandering as much/ 2. If your throwing some boxes together from an
old crate it is probably 1/2 mtrl. Screws are to big but brads are
not. Before you glue, strike a center-line where the nails will go.
Pour on the Elmers. Then sight down the line as you brad the box
together. By looking down the line you can start the nails exactly
straight and square. love a cheap shot! Ron BTW Two reasons motor
oil for a lathe is a bad idea: 1. Lathe spindles do not get above
200 degrees. If they do, you'll be replacing the lathe 2. Engines
have a 30+ psi oil pump and oil filter. Haven't seen too many bench
lathes with this option...but I'd like to. (2089) |
| Tooling |
| Holes can be made
larger by grinding drills off-center. That is, 1 lip is wider then
the other. This automatically forces the hole over-size. And happens
more often then not. Any dull edge will force an opposite edge to
cut deeper, up to a point. This can be seen by bluing 1 side of a
drill and using it in steel for about 1/4". When I sharpen a drill,
I start by putting a ref. notch on the back of 1 flute. This then
reminds me which side is cutting. Reamers that have a dull side may
tend to force the other flutes to dig in more. Now how much larger
are we talking about here? Probably little more then .003-.005. OTOH
you can make a smaller hole with a drill. Just stone the corners a
bit to force the sides to cut more. The stoned edges act more like a
pilot then a cutter. Because they are smaller and dull. Then there
is the drill or reamer in the tail-stock that is off-center. Or held
in the tool-post off-center. Ron (2126) |
| More cutting
remarks |
| Interesting remarks
on carbide inserts Chris. I must admit I have not used carbide since
1985. I have run into tough material since then. However, having the
use of tools I got prior to that date, carbide was not a big item in
my small stocks. I use the 1/2X1/2 in other applications besides
turning. They are great for fly-cutting and shaper work. I should
have mentioned in my last post that I can shape them for almost any
cutting job using a common alum/ox wheel. And that if you made a
hardwood wheel, 2X6" and charged it with 15,000 diamond paste ($20)
it will polish an edge on HSS or anything else, that would hold up
longer then ordinary 200 grit white wheel. If there are no pits and
gully's in the edge of a bit, it will cut cooler, faster, and
longer. Guess that's why firms like MSC sell so many diamond
finishing wheels. I can only imagine a carbide tool bit you can see
your reflection while shaving with it! Ron (2198) |
| When yer hot
yer hot! |
| High speed steel
brought us into the 20th century. Prior to this we were pretty much
at the mercy of our own wisdom, (or lack of it!). The old carbon
steel bits were a temperamental lot. I don't care who made it, a
carbon drill would always leave you in a 'lurch' at the wrong time!
(pun intended!) Back then we had to really baby those damn tools!
But I must say I still have a great respect for carbon steel. It is
still an excellent steel for working temps. lower then 300F. As for
heat-treating HSS, DON'T! Even though I regularly cherry mine when I
am doing rough work at the wheel. You can get it that hot for brief
periods of time, don't push it. Ron (2207) |
| The old grind |
| The secret to
grinding is to start by hogging off all excess stock with a 3/16 or
1/4 cut-off wheel. Then take your time with the final shape and
sharp. I use a little 4" bench top with little HP. This way I can't
burn my more delicate carbon wood tools. regards, Ron As in other
entertainments, grinding tools must be kept wet and moving...lest
they get burned and worn to quickly (2239) |
| Leftovers |
| My own tool holder
system was built by the DoveTail T Mfg. Clinton NJ, (no wonder it's
a tight fit LOL!) It accepts anything you can fit into the slot up
to 1/2. The retail is around $400 NOT cheap but worth it. I can take
a cut, remove the tool, and replace it, keeping the same tolerance.
This is what you want in a tooling package. When you buy a cheap
tool, you get what you pay for. When you buy a cheap knock-off of a
good tool, you get a cheap tool with an inferiority-complex. I have
been told that there are good tools coming from China. I'm waiting
to see one. If I say anything more on the subject, I'm liable to
future litigation. Steve, I have an old Jet milling machine built by
Jet in Tacoma, Wash. USA. It is a survivor from a high school metal
shop equipped with DRO. Head swivels in 1 direction only. Needs to
have the table planed so I can scrape it. But I love it
none-the-less. I wouldn't touch a Grizzly with a 50 foot chop-stick!
(my apologies to Poles, THEY can build tools!) Get an old Tacoma
Jet, and re-build it. Put in new head bearings and scrape the main
deck. You could put $1000 into re-build costs and still end up with
a better machine. Now there is a bean-counter that will scribble for
2 minutes and proudly announce I'm full of $**t. What he doesn't
know is that if you use inferior cast iron and other poorly smelted
materials, no matter WHAT you decorate this turkey with, it'll still
get the runs on your wallet. Ron (2260) |
| Quick parting
check list |
| Most of the posts
on parting-off contain good advice. I say most because there is
always going to be a better way someday. So what causes a parting
tool to break? - spring from loose gibs to loose head-stock
bearings. I run my P/O tool upside-down with the carriage
binding-nut tight and my cross-feed gibs snug. This way if my tool
tries to dig in, it will ride up on the cut instead of snapping off.
Also keep that tool from to much over hang. -dust and chips, that
are always present at the cutting sight. Make a fast drip cooler by
hooking up a coffee can equipped with a valve and 1/8 copper line.
Use a 50/50 diesel 10W light oil. You can use this for all metal
cutting. -beef, if you have a little 4-6" lathe your C/O size is
fairly small. Do not attempt to cut a 2" piece on a small lathe,
unless you spend a lot of time sistering the cut. -sharp, keep your
C/O-tool sharp. In my case the blade axis is square to the work; but
my tool has a slight skew to it. This way the part comes off before
the parent material is faced. My cutter is sharpened and honed to a
2 degree skew, a 5 degree slope on top. IN GENERAL, the effort to
reduce these variables will reward you with better results and fewer
trips to the ER. Ron (2337) |
| Being wary of
wavy |
| Good idea there
Dennis. Use the 4-jaw chuck as a flycutter. The piece of square bar
stock should hold a 1/4X1/4 tool bit with almost no flex. Depending
on how big the part is, you may even consider making it a
double-ender. Just use the milling attachment as a depth-guide to
set both cutters against. I have run some pretty old and worn
equipment in 30+ years. In every case the boss man wants the same
thing, good work on bad machines. A cutter riding on the waves of
time and wear will make a long shaft resemble a Newell post. The
problem with spot scrapping is that you are trying to rectify the
absence of metal with the absence of metal. I wonder if this will
make things worse? In some reading on scrapping, the author always
scrapes the whole bed, not just a spot or two. Jeff, I thought about
your idea to use a boring head as a thread-cutter. Ummm... it may
not work. Single-pointing a thread requires that the tool ADVANCES
at a 30 degree angle towards the work. Thus building up a thread
with each pass. Now I may be wrong. I have seen boring taps used on
CNC machines. They look like bottoming taps that go in and form a
full thread in 1 pass, (presumably). Another thing to consider is
careful alignment and holding the part so it does not twist from the
torque. One or 2 tooling holes can be used as a spanner somewhere on
the set-up. This has the advantage of allowing the operator to
remove and replace the part without losing your 'place' on the
thread. My last thought here is one of preference. I have dealt with
a few machine tool supply firms in years past. After trying some of
the firms mentioned in previous posts, I come back to MSC every
time. The prices may not be cheap, however I get preferential
treatment having been a very long time customer. You stick with what
works I guess. Ron (2464) |
| Tooling around |
| Never had much use
for indexable tooling myself. Oh sure, if your into high production
and can afford it, IT is great. As long as you can get replacement
parts and are willing to pay the high price for them then go for it.
However, long ago I adopted the philosophy of being able to control
tooling from a raw material to a finished product. If you know HOW
to make something, you needn't depend on someone else to do it for
you. As for 4-turret posts, they are only good if your doing limited
production, short shaft and face work. Otherwise they take up way to
much room. Make a set of tools using stainless round stock (somewhat
tough) for your boring bars. Start by making a simple holder from
CRS that puts your tool on center. For a 9" SBL use a 2X2X2.5 square
piece of steel. Offset the bar hole and use 1/4-20 SS. The bar hole
should be 1/2 or 5/8. You can mill or saw a notch in the end of your
boring bars and then have a local welding shop TIG 1/4X1/4 cobalt
blanks to them. Then grind to shape. Tool steel and SS weld real
good. For the rest of your tooling use a sharp alum Oxide 80g wheel.
Set the tool stage for 5 degrees and grind away using the 123 method
(see the archives). Top grind a slight compound rake, front angle,
and side. Give it a few licks with a fine India hand stone. All
other tools follow this same idea, regardless of shape. Ron (2529) |
| Making new
lines |
| Lurch, The markings
on your lathe do sound out of tolerance. This is how to fix this.
GET a Devcon kit for atomized steel, and a file. Smooth over the
mark on both sides of compound. Erase the hash-marks with the devcon
and allow to dry. Pre-warm the area with a heat-gun after cleaning
it with acetone. Carefully smooth the area flat with a sharp file.
Next, take a small piece of 600-G wet-or-dry and fog the surface so
your new mark will be easier to see, (Us 'ol farts love this as we
is blind in 1 eye, and cain't hear out of the other!! G indicator in
the chuck and using the side of the compound that has been milled as
a datum. Use a scale as a guide and strike a new line with a graver
that will give a clean deep line. You may want to experiment with
this until you get it right. The short answer is to just zero the
compound and apply a line through a dry spot of layout-dye. Ron
(2559) |
| Keeping it on
the level |
| Use your
spirit-level with a dial indicator. Place the level where you want
to check for plumb. Use some sturdy object that can be used as a
separate base on which to hold the indicator. By placing the stem
near the level, you can watch the dial as you torque the wrench. Use
a long flat bar across the ways, (at least a foot long) as a surface
to indicate on. You should be able to level your machine with a high
degree of precision. FOR the sake of runn'in my gator here is Rons
shag-nasty method of making things level. 1. When I mill-right a
machine such as a lathe I make sure it is on a floor that doesn't
tend to 'walk around'. 2. Start by marking all sites where the level
will test. Use felt marker. 3. Check under the chuck and end of bed
for level. Be sure your level sits on the bed without being cocked
in any way. Adjust left and right until the length appears plumb. 4.
Now repeat step 3 seeking level front to back. Do this by turning
level 90 degrees on the same spots used for step 3. 5.Go back and
check plumb for length of bed. You now eliminated most of the twist.
Final plumbing can be done using the cut and check method using a
piece of bar stock. regards, Ron PS. WHOOPS! I should mention that
you make a good sturdy jack-screw under each resting surface. DO NOT
USE WOOD OR STEEL SHIMS!! (2565) |
| Jack's screws |
| Tom, Any jack-screw
is a basic nut and bolt w/washers. If you have pads under the screw
w/dimples so that the pointed bolt has a place to nest, it should
work. I of course had to make a set of 3/4-10 screw-jacks that were
single-pointed, and had nuts made from 1/2X2X2 hot-rolled iron. Ron
(2587) |
| Walk-about
tips |
| It is possible to
turn very accurate shafts between centers with any chuck; no matter
how worn. Chuck a 2" piece of 1" round stock in your lathe, and turn
a 60 degree point on it. Then get a piece of 1/2X2,3... wide bar
stock and drill 3 holes in it. 1 for the part 1 for the bolt,(3/8-16
to act as 'dog-tail') 1 for 1/4-20 sq.hd jam-screw. You'll have to
put center-holes the old-fashioned way in your drill press. In the
meantime here's some more shop-helps: I found out the reason you use
grease for cone-pulley lub...it don't leak out as fast...!
Walk-a-bout drill: If you want to keep the drill from 'walking-off'
center while you begin a hole, make a drill guide that bolts
directly on the compound. A chunk of steel with a hole drilled and
bored just like it was an on-center boring-bar holder. This can best
be achieved by bolting the block on the compound and after squaring
it to the chuck, drill and bore using the head stock as a
tool-holder. Then you can make as many inserts as needed to hold
almost any drill, tap, reamer, or die, on point. This is such an old
trick, I'm surprised it hasn't been mentioned before. Quick pipe
center: I had a fast, cheap-N-dirty job to do for a local welding
shop yesterday. Placing grooves 5/16" wide in the ends of 12" long
by 2 1/2 hot rolled pipe. I didn't have a bull center for a pipe
that big. I drilled a 3" chunk of CRS 3" long, and pressed in a
piece of yellow brass. After turning it for true, and boring a 60
degree conical hole for my live center, I did the job. The pipe
center floated between the pipe and the live center. Worked real
good. Ron (2848) |
| Nutz |
| Before we order a
case of nuts, may I offer an opinion? Installing a new cross-feed
nut only addresses a part of the problem. You have 3 areas of wear;
the ways, the nut, and the screw. To do it right you must re-work
all 3.First thing I would do is to even up the cross feed screw
using lapping compound and a piece of hardwood what's got the thread
for the screw tapped through it. Even that sucker out until you get
a very even feel end to end. THEN make the nut to match the shaft.
Finish both by marrying them with rouge. A pinch-nut does slow down
the wear, however, careful cleaning and adjusting of your lathe will
solve problems before they become problems. The dial on my 10" is
not large. About an inch. Depending on what I'm doing for a job, I
use an indicator to finish any close work +/- .001. The indicator
can show you movement by virtue of its spring. This does NOT show
you what's going on at the cutting-site. OK so it's a pain in the
a$$ to rig this up all the time. But from experience I can tell you
that every lathe I have ever run from La Blonde Regal to Cincinnati
and Rockford, no lathe is gonna repeat at the same setting, period.
They just don't, too many variables. But if you want the cheap and
quick trick to closer machining, do this: 1.Always keep a finishing
tool ready to do just that, finish-cuts. Make it so all the faces
can show a reflected image. 2. Keep a magic-marker on hand. It is
more accurate then a dial. 3. Do a spring cut prior to finishing. It
takes the worry out of being close! 4. When your within .005 of
finishing, change tools and apply the ink. Then use this as a
bench-mark to pick up the cut. regards, Ron BTW- What is the
designation of the floor model SBL? I'm speaking of the model that
has the motor under the headstock; and the on/off switch above the
bed. I know where I may be able to get one but must know the model
class first. Also what ya'll think is a fair price to give to a
local school? This is important to know before Friday. Ron (2889) |
| Ron, For very fine
work, I have used a tenth indicator with a magnetic disk on the back
of it. It usually fits somewhere on the saddle to indicate the
movement of the crosslide. They aren't as bulky as the magnetic base
stands with adjustable arms. (although I am using one now to
reference Z travel). I will say I have used Hardinge Lathes that
would repeat in the tenths. These weren't in the best condition but
had Sony DRO's. I was cutting bronze so not much tool wear. Also, on
C to A or B conversion, I don't remember if it was mentioned, but
the crosslide lead screw is different too. The A's and B's should
have a gear tooth pattern (sort of) on the body end by the ACME
thread. This is for the power transfer to the cross slide lead
screw. You should be able to see the difference in the SB diagrams.
Tom (2891) |
| Chuck'in the
weight |
| The weight of the
piece is calculated at the drafting board back in Indiana. Unless
you are turning mercury, I wouldn't sweat the tonnage. Just keep the
bearing well-oiled. I have had to do some unorthodox work on a
lathe. At one plant, a well drilling-rig came in to be straightened.
It was the gear-drive that made the bit turn. I loaded the rig into
my old Hendy floor model 16X40 lathe...made back in 1899. The main
drive-shaft was bent. I had to chuck the d-shaft in with a
dead-center. Then use the back of the bit holder as a ram. Heating
up the bent portion with a large smith-tip on a cutting torch; I
cherried-up the bend and nudged it back to straight. It did not seem
to bother the lathe to much. Later that day I was coming back from a
staff-meeting in time to see the plant owner dressing up the ways on
the lathe next to mine...with a body-grinder!!! He was distracted by
a thud, (my jaw!) and calmly replied that it was a bit tight, so he
was just 'evening things up a bit'!! Unless you need to administer a
high-colonic to someone in the shop, I would recommend this
procedure. This is the same guy that uses a high-freq. welder coil
to find metal splinters in his fingers. See they cherry up so you
can find them easier!!! Ron (2964) |
| Keeping it
simple |
| Get a piece of tag
board about 1X2' and do some drafting. Actually more like
sign-making. There are lots of figures and rules we constantly
forget and then have to go dig up someplace, (if you can find the
damn book!) Some of this info isn't even IN the book! Like: What is
the max. jaw-opening before you start losing jaws.. What is the
safest roughing-cut before you hog in What mark on the dial is for
odd or even threads ...and such like. Having this info at a glance
is very convenient. Keep a list of things to be done while doing any
project. Anytime I do a job, I like to keep track of any road-blocks
that may slow the job. Often times it is something simple and
inexpensive. Like having a place for a file next to the lathe. Then
when your afraid the old battle-ax is looking for something to
natter at, you can be safely barricaded in your shop claiming to be
working on something important. Ron (3008) |
| Steel & stuck
chuck |
| MORE ON STEEL:
Reading Eds post on steel reminds me of my tool-building days of the
70s. I built most of my tools out of CRS or similar stock. I had
access to a complete shop, so case-hardening a piece to 3/32 depth
and grinding was no big deal. I took the time to 'normalize' my
tools during the finishing process. My tools went to the fridge to a
200 degree oven and back, several times. This gently smoothes out
the wrinkles, (and stretch-marks) in the steel. 30 years later my
blocks, vises (the legal ones that is) and angle-plates are still in
spec. I like CRS because it is clean in dimension and cheap. My one
big problem is getting a good turned finish. I have tried using a
round-nose, flat-nose, sharp-nose, to nose effect. Lately I have
gone to finishing with a cross-hatch pattern using scotch-brite or
using a fast-feed, light-cut thread pattern. STUCK CHUCK-ROAST: If
your holding a hammer any larger then 16 oz. put it down. My bias is
about to surface! Go get a 2X4 about 3' long. place it in the chuck.
Now attach 5 lbs. to the other end of the lever. Add to this some
warm kerosene, and apply this to all joints that need un-sticking.
Tap the chuck using a 1 lb. hammer and a wood block. Now go away.
Come back in an hour and repeat the ritual. Take your time. After
all how long do ya think this thing has been in this condition? I
have managed to un-stick assembly's that were tighter then an Irish
Priest on holiday in this manner. (OK I admit I learned this from an
Irish machinist!) The slow constant pressure of the lever will exert
pressure without you being there. The warm Kero applied often will
seep in ever deeper. The worst damage will be to your patience, not
the chuck! OK SMARTY HOW BOUT MY COLLET!? Glad you asked that
question. Set up a rig that will keep the rusted joint wet with Kero.
A gallon of it may be needed. You may wish to recycle it. If you can
slip a rod with a nut and washer on the end through the tube . Use
the tail-stock and chuck to put tension on the rod and collet. When
the rod begins to slip in the chuck, you have enough pull. Warm up
the collet using a 125 watt outdoor floodlight. When it is just
scary-hot tap with 8 oz. hammer and hardwood block. Now go away.
Repeat tapping and warming once an hour. IN GENERAL No matter what
your approach, using a little of everything will work. Time works
better then force in this application. And using Kero instead of a
hammer is a better idea. Ron (3087) |
| This N dat |
| How to fix any
run-out. Install a set of soft-jaws and bore them so that they have
a 1/8" land. The cheap fix is to use a 4-jaw chuck and skip the soft
jaws. That is providing you have one. The impact-wrench idea gives
me the willies. That much energy hitting that spindle at once may
loosen things that weren't meant to be terrorized. I have heard 1
suggestion that stated you just stone the other 2 jaws (VERY
carefully!) to even them up. Checking frequently with a dial
indicator. I have never tried this myself. Ron (3099) |
| Drills |
| The problem with
head stock shafts is they were made to turn metal, not do a stand-in
as a torque-wrench! There are square shoulders on these things that
will part very nicely when pressured to. But I like the dry-ice
idea. Hmmm, Someone asked me about drill brands and types. Paul
maybe? Ummm, the split-points are OK provided you know how to
sharpen them. These tips have a little built-in pilot that is
supposed to help start the drill. Personally I use a 1/4"X 3" long
center drill to start holes in my milling machine, or in my
hand-drill. They give real nice control. As for brands, stick with
Chicago-Latrobe USA. Any brand on this side of the puddle that sells
at a sensible price AND is not afraid to give an analysis is worth a
look. I stay away from Silver Demming for the simple reason that
they are not up to the name. Translation JUNK!! Case in point. My
friend and compadre -in- crime Tim bought a set from an off-shore
import firm, (guess who?). They had a real nice steam oxide looking
finish to them. The set was 5/8-1 1/4 with 1/2 shanks. The ends of
the drills looked like he had done root-canal work on a T-rex with
agate caps! The ends were chewed! I asked what the hell he DID to
them!! answer? Drilled some CRS. A dull file told the story, soft
drills. Great for pine. Unless they are at least 20 years
old...forget it. Ron (3108) |
| Oil of vitriol |
| Just for the
record, there is one other way to loosen up that chuck. It's called
navel-jelly. Basic jellied acid. Sulfuric I believe. It will work
for sure. I use it to sharpen worn files. It is also great at sizing
reamers and other cutting-tools. It is a bit drastic though.
regards, Ron (3112) |
| The primary acid in
Naval Jelly is phosphoric acid, if you need an non jelled version
this is also sold as metal prep at most auto parts stores in their
paint section. It converts trace rust from ferric to ferrous oxide,
and does a light surface etch to improve primer adhesion. For
prepping metal you dilute 1:7 with water. I'd go for Rust Buster or
Kroil over acid etch in this application. Stan (3113) |
| THE PROCESS: To use
navel jelly...a product from the crusty Seamens Retirement Home:
1.Choose a vessel that can put up with all that guff, like glass for
instance. 2.Tie up your items of rust using USN regulation bailing
wire, (spar the spit please!) Immerse in erstwhile solution and
place some kind of lid on it, loosely. Now go away. 3.Read War and
Peace, (the abridged version. 4.check your soup by lifting out the
items. If you come up with bare wire, your items are probably
clean...and a bit lean. 5.Drain solution back in the vessel it
arrived in, (all liberty cancelled!) and retrive items. Have another
vessel standing by filled with water. Dunk items and shiek, sheckel,
and roll. 6.Retrieve items and place on paper towel. Now dry them,
OR place on old cookie-sheet and dry in on hot plate. Finally oil
your tools well to prevent rust. HINTS: NEVER USE ANY ALUM!! (Old
sailors hate this stuff...ask a survivor from the HMS Shefield!)
Since you will find this process sooo neat, I'd make up a dedicated
box of heavy cardboard or 1X2 and door-skin. Keep everything in de
box so's all you have to do is lift the lid and let the grem...oops
sorry and go to work. My own box says PANDORA (with a sailor in
drag) on the side, but you can do up yer own icons. This help? Ron
(3152) |
| Brass nuts |
| I got this here
brain-storm this AM while watching the eagles soar over the house.
The thing is, all these nice new nuts will work better if they are
custom fitted to each lathe. See there are worn spots where the nut
will be looser. Then there will be spots where the nut will be
tighter. When the nut works in it will be a little better then the
old one; but it will still be loose in spots. To fix this in the
field is easy. All you need is to make a set of setting and lapping
rings. MAKE THE RINGS: Start by making the master setting ring. This
is a disk of steel 1 1/2" in dia. and 1/2 or 5/8 long. It can be
threaded with the tap that matches your screw or single point it on
the lathe. Before slitting it to make it adjustable, drill and tap
it for a 10-32 socket head screw. Oh yes and don't forget to knurl
it too. Make the second one of these out of brass. Both setting
rings will be adjustable via the turn of the screw. LAPPING THE
SCREW: The first thing is to set the master ring. This should be the
most worn spot on the screw. You don't want to start on an unworn
spot. Otherwise it would result on a loose fit. You may find that
after doing this, it will be hard to take off the ring. You want a
light drag fit. So take your mic's and measure the ring O.D., back
off the ring, and re-set once it is off the work. I should have
mentioned that it would be a good idea to mark off the high spots so
you know where to work, and what to avoid. Depending on how bad it
is, a drawing showing the high spots can be of help. Begin lapping
using #220 grit in 10wt oil suspension. As you work, the lapping
ring may become loose. It's suppose to. Check your progress with the
master ring after rinsing off the grit in a Kero bath. You want ALL
the grit off to check the job. Depending on the wear, this can take
hours. The lapping ring may need to be set often. Use power tools to
spin the screw only if you feel you can handle this. Otherwise stick
to the Armstrong method. If you did it right, you'll wind up with a
screw that is within 10ths of being perfect. Then when you mount the
new nut, the lack of tight spots and almost no lash will amaze you.
Ron (3164) |
| Gett'in da
woolies! |
| Brill-O Pads are
death on ways!! I use bronze-wool and diesel fuel. The pads are very
useful for marine wood work where little bits of steel wool would
catch and rust in the deck work. Also good for indoor uses where you
don't wish to scratch stuff like glass or steel. Not cheap though.
Diesel in a spray-bottle is better then WD40, and cheaper. Try
buying a gallon of WD40 for under $2!! Ron (3301) |
| Dials and a
Barbie cook-out! |
| About your
threading dial even need one! I managed to keep a whole railroad
going with no threading dial. All I did was to leave the half nuts
engaged an back off the cut at the end of the run. With a travel
dial and some practice I could even do blind holes. And so can you.
I recommend everyone put out the $20 (MSC) and put a 2" travel dial
on their lathe. RONS SHAG-NASTY SIDE DIAL 1.It's a 2-part clamp. You
only need a band saw and a drill press to finish it. 2.Get the top
piece 1X2X3 inches of CRS. Lop it to length after figuring where you
want it to land on the ways. If you have crowns, make a mark for
center,1 for the dial on the end, and 2 for the clamp holes. This is
nothing more then a glorified machinists clamp. 3.Band saw the
cut-out for the ways as needed. Finish this with a file. Now drill
for the clamping bolt,1/4-20 thru both parts, top and bottom. This
bolt will do all the clamping. So decide weather you want the head
on top or on the bottom. It's a matter of space and convenience.
Then clean out 1 hole for clearance. 4. Now decide where you want
the travel dial. Drill a #7 hole and tap for a 1/4-20. A min. of 3/4
depth and use a bottoming tap to finish. Depending on where you want
the dial end to hit the carriage, it may be necessary to add or
delete material on the end of the block. Most T-dials have a lug for
a 1/4 hole 90 degrees to the length. In my case, I used a spacer to
put my dial where I wanted it. This was so I'd be able to tuck it
farther in front of the headstock. 5. Now put the last #7 hole thru
one of the clamp jaws. This will be adjusted so your clamp jaws
remain parallel. IN GENERAL: It's all in the planning. Some guys
want to do a mock-up with a 2X4 end cut. Whittling it down with
their band saw and mill until it is just right. One tip is to make
it so's ya don't need any tools to move or adjust it. The dial stays
put on the block so all you need is a knob with wrinkles to move the
stop around. Fine sand the pieces and chuck them in the coals while
your cooking up the steaks for your "Side-Dial Shop-Warming Party"
When they look dark and nasty (not the steaks!!), Chuck them in that
bucket of old crank-case oil you insist is still useable. I use a 5
gallon STEEL bucket with lid filled with old oil. Use an old piece
of scotch-brite to shine up the piece when cool. With some diesel it
will come clean. Add a fried chicken wire basket with bail added and
handle removed. Makes a great display when you quench. Ummm,...
better do it outside away from the bary-Q!! Bone da Patiet!! Ron
(3352) |
| Points of
interest |
| In the HINTS AND
TIPS DEPARTMENT I offer you the Ron Cheap-Shot tool for centering.
Go buy a 6" pocket scale with depth clip, or a piece of SS 1/2X6X
.032 shim strip. Carefully grind both ends square. Stone all edges
so they don't cut you or your nerd pouch. To use, simply place it 'tween
the tool bit and the work. If it tips away from you, the tool is
high. If it tips toward you, the tool is low. If it sticks straight
up, your centered. On some SBL's there is a mark on the tailstock
sleeve that shows center. Personally I don't get to fanatical over
where my tool is. I've used the scale-tipping method for over 30
years without a problem. ...and speaking about accuracy, here's a
few tid-bits to think about. In his book on the use of hand tools,
Aldren Watson advises the student on the hand and eye: "When
learning the brace and bit, use a square or block to act as a guide
while boring. Keeping in mind that the square is only a tool for
learning in this application. As the student becomes proficient they
will not require such tools as they will be able to bore holes on
location square or canted BY EYE, and have them be perfectly
aligned." When you reach for a mic or vernier, remember that your
hand and eye can be more accurate. Cut 2 pieces of steel and face
them in the lathe until they are of equal length. Use only your
fingers as a 'feeler-gauge. Wanna bet you can get within .0002 of
being the same? Sameness equals accuracy. A piece of wood or metal
can act as a very accurate gauge when setting up and running many
parts. By doing the same thing to each part insures a well machined
part. SAMENESS=accuracy. Again no mics. When the old farts were
using steel rules and calipers to check their progress, it was their
'feel' that insured a good part. To a large extent, the art of
scraping is based almost solely upon their eye and hand to keep a
12' flat bearing at 80% pointed with a total deviation of .0002 in
12'!!! I've seen it done. OK what's he go'in on about now!?? just
this...IT'S THE MAN NOT THE MACHINE!!! I can think of no better
place to learn intuition and feel then in a first generation machine
shop. It requires all your given talents. By using them, you hone
what's already there. (Feel the Force Luke!) Ron (3395) |
| Keeping the
edge |
| Back in the 60's we
used regular vinegar on galvanized steel prior to painting. It did a
nice job of etching without causing retching! G done on aluminum as
well. It should etch the surface without boiling it away. I have a
headstock cover for a SBL bench model. Not sure what it fits but
will part with it for reasonable $. TODAY'S CHEAP-SHOT: Ever use a
rubber impregnated wheel for honing? Expensive ain't they? So try
this: Get a solid rubber tire off a lawn-mower...preferably your
own, that way the 'ol ball chain can't natter you into doing the
lawn! Mount this on an arbor made from a long bolt,2 nuts and 2
large washers. Put this in the lathe or drill press. Next, smear on
some clover-leaf #220. The tread will hold the grit. Now take a
lathe bit and hone it so it looks like a mirror. This will work.
It's the same principle as a BayState Brite Boy. I have used these
wheels in the aero-space industry for polishing radius's on
stator-vanes. You will get an incredible polished edge on almost any
tool, be it lathe bit, chisel or drill. Just remember to hone with
the edge trailing the cut. IOW you don't want the tool to dig into
the wheel. As your facing the grinder the edge is facing AWAY from
the wheel direction. When doing carbon steel, keep a bucket of water
handy to keep yer tool cool. Ron (3415) |
| Tooling around |
| I have had the same
trouble with my own cone-pulley/back-gear. With the discussion going
'to grease, or not to grease', I said the hell with it and used red
oil. Mystery Marvy oil, ya can't beat it. Makes a good after-shave
if your going to be at a party of wifies intellectual at-work
stuffed-shirts! After they strut their stuff of "I got out of ENRON
while making a profit" I just remark on the progress I am making on
my P-38 Lockheed Lightening restoration project. The definition of a
good machinist is one who can cover his own @#$-ups and still be on
target. This goes for apologies and explanations too. Q: How fast is
fast when grinding HSS? A: There ain't one, IMHO. If you cherry up a
tool bit and then it don't cut, then it weren't HSS to begin with!
Or why I only buy USA, (Oh God! Here he goes again!!) The only
exception to this rule is TANTUNG,. At red heat, it will crack. As
for buying a grinder, 3450 RPM is fine. You can build yourself a
good grinder using a good used motor and some pillow-blocks, and
assorted end cuts from the local welding shop. For $150 you can have
a $400 unit. I have 2 grinders. One for shaping, 1 for sharpening.
The shaping grinder has enough balls to do what I need;8" fine wheel
on left, 3/16 C/O wheel on right. The other grinder is a small 4",
has no balls. It'll stall if you jam anything into it. Makes for an
excellent wheel for dressing high-carbon steel and HSS bits.
Whatever you decide, be sure you do not exceed the max rpms of any
wheel. They tend to fly apart when spun at 300,000 rpms G Now if you
have an old lawn mower wheel, scrape out all the dog dung in the
grooves. Mount a bolt-arbor thru it, and put this into your lathe.
After covering the ways, rub some fine valve-grinding compound onto
the wheel. Strop your tool-bits with it. Being sure not to let the
tool dig in. You will get a brilliant finish. You have just made a
Bay State Bright Boy finishing wheel! Ron (3585) |
| With your
clothes on! |
| This is just 1 of
many places where the paths of a amateur telescope maker and a
machinist cross. ATMs need the skills of even a 1st year machinist.
Worm wheels are very important critters to astronomy. They are
attached to the polar axis of a telescope and keep the star image in
constant view. Having the ability to make these sets so that they do
a good job of tracking, gets instant attention from scope builders.
The largest of these worm-wheel sets is the main driving gear for
the 200" Hale Telescope. Over 6' in dia. I believe. For the purpose
of a threading dial, as long as the repeatability of the dial can be
relied on, small inaccuracies can be over-looked. You could probably
make a direct index plate as was suggested and use this to
pre-generate, (gnash) your teeth. Then go back and finish mill using
a tap. Then clean up with 600 grit and a piece of threaded acme
stock, (marrying). I have seen adverts in journals such as Sky
Telescope for worm-gear sets. They can easily run into the thousands
of dollars. O2 getting low or am I wandering among the stars again?
Both! :-) If you guys want to get into something that will be a
challenge, an added income, and a way of gaining a LOT of
respectability...make these and other parts for ATM's. It's the most
fun you'll have with your clothes on! Ron (3829) |
| Don't lose
your temper |
| If I had my
druthers for a mill in limited space and cost, it would have to be
an American-made JET from Tacoma Wash. The model I have takes up
half the space of a Bridgeport. I imagine you could pick up a used
one for less then a couple of grand. I am sure it was an oversight
but in his description of making that worm wheel Dallas forgot to
mention the hardening and tempering process. And since we are on
this subject, I'd like to clear up a lot of mis-information about
tempering. In his book "Tool Steel Simplified." Palmer offers this
description of the tempering process: "This operation involves the
re-heating of a hardened tool to remove the stresses during heating
and increase its toughness." That is the short explanation of
tempering. The tool-maker wishes to draw the strains out of his work
at the same time he imparts a toughness into it. Some of the
hardness is lost in the process. But this is preferable to a
glass-hard tool that breaks during use. For some reason I hear more
heated discussions about tempering then any other metal- working
topic. Probably because there is a little lusty blacksmith in all of
us! :) So when you hear the term 'drawing out' the tool, (IOW taking
or drawing forth the strain in a metal) ask the speaker what he
means. The book advises a 1 hour tempering time for most work.
However the more complex the tool, the longer the tempering. Keeping
the correct temp. is VERY important. If you need a harder tool,
start with a harder steel. Ron (3872) |
| Runn'n my
gator |
| Some notes on
boring: -short tools are welcome, they don't cause a lot of chatter
during insertion -fatter is better then thinner -being on center is
not as important as being sharp -wrapping a rubber band around the
base of a long tool cuts the chatter -use a little oil -reverse your
feed near the end of the boring operation, the last .005 should be
spring-cuts while you back out of the hole. This decreases
'bell-mouthing'. -worn out end mills make great boring bars. Hand
grind both lips by eye so they look like the original tip. Mount
these in a home-made block that allows the BB access to the hole. If
you have QC tooling, just put them in the boring bar holder. -for
short C-bores use a drill sharpened like and e-mill. ANY drill can
do this. Ron (5547) |
| S'more-lore |
| Kerry, There is
merit in what you say. There is also another reason you back out of
a cut. The leading edge of any cutter will always wear down before
the trailing edge. It is this trailing edge on a boring bar that is
sharper. Also, if you let the cutter dwell for a second, it will
allow the tool to cut a bit deeper. When I use the term 'spring-cut'
it is in reference to any tool on the lathe or mill. At the end of
each pass, you go back over it without moving the dial. In the
lathe, stop the headstock and retreat back to the end of your cut.
In the mill, just go back over the cut at the same rate of movement
to wince you started. A return climb-cut on alum or steel will do 2
things: 1. Makes for a smoother finish, 2.Shows you exactly how worn
your milling cutter is. Ron (5571) |
| I do the same thing
on the mill. except backwards I climb cut first then go back
conventional. on the lath I only do it either when boring or when
turning aluminum, or CRS. Do you turn much tool steel Like D2,M2, or
D7? don't try that with this stuff it won't cut you can't sneak up
on it. you need to leave at least .025" for a finish pass or leave
enough to grind if you try to take a .005" finish pass it will have
a bad finish. Kerry (5572) |
| Shuck and bump |
| Kerry, haven't
worked with tool steel much lately. I do know that the tougher
steels do require more attention to finishing then most metal. I
usually set up my finishing tools in advance in anticipation of the
work. A finishing tool of HSS-MOMAX with a polished tip usually
serves as a good finisher for almost anything but CRS, (Mikey steel,
he hates everything!!) My 2 sheckel wisdumb on shuck and bump for a
sloppy cross-slide is simple. Your nuts are wore out and/or your
gibs had da radish. Both can be fixed. If the gib is a simple flat
strip get some brass and mark out the dimple locations using the old
gib as a template. Just lay it next to the new piece and step off
the locations. Dimple these with the correct drill. Check the
cross-slide for a hole in the middle. Almost any old lathe will have
a worn spot in it. This can be scraped flat by someone with the
right tools and experience. You can always go to the Moglice people
for help. Just go to your favorite metal-working place on the net
and type in MOGLICE. You'll find them. If the nut is so sloppy you
fear a failure during critical performance, get a new one. Or go to
the archives and look up the articles on making one. Were it me, I'd
advise you to just buy a new nut and screw. Ron (5589) |
| Disc facing |
| I once had an
engineer who delighted in making impossible drawings you could not
machine. One was a piece of delrin 2X6X12 inches. It could have no
marks on it and could not be clamped, but had to be dead flat. I
milled a piece of 1" jig-plate so it had an XY shoulder. I glued the
delrin down with super-glue. Took light cuts. It came out dead-flat
and gave that engineer a real fizzy attach, (boy was he pissed!) Now
to your problem. Depending on the thickness of the plate, you can do
2 things: 1.Center drill a tiny hole in the middle of both sides. Or
just drill a thru hole w/champ. Set this in a face-plate with a
small jam-strap against the rim. This serves as a friction clamp.
Take light cuts while facing both sides. 2. Get some Dev-con
adhesive and mix enough to put a thin ribbon around the inside edge
of the disc. Use the center hole to align it on the plate. Lightly
clamp so that it has a bit of squeeze, but not enough to deform the
plate. You want this thing round AND flat. Be sure to roughen and
clean both surfaces for side 1. Side 2 can not be roughened, but the
machined surface you turned will be fine for a 1 shot deal Use
lacquer thinner to clean all grease and oil. This will work.
regards, Ron BTW You can remove the plate with a bit of heat and a
thin paint-scrapper. (6238) |
| Trying to be |
| If your having
bearing trouble and wish to tighten things up a bit without using
God Glue; try dimpling the shaft with a prick punch . Or using a
knerling tool to raise a shaft dia. .0010. As fro knarling tools on
a lathe. Unless you use one of those clamshell or hindge types DON'T
DO IT!!! These tools will ruin your soft bronze bearings over time.
Remember, when you slam that tool into the shaft it directly forces
your bearings into extraordinary wear mode! I only knarl alum or
delrin NOT STEEL. I'm gonna try to get back to regular postings. BTW
that thar tool post grinder is still on the market. If I had the
sheckels, I'd buy it in a heartbeat. Will try and post the
particulars. Ron (9060) |
| Scraping II |
| In small
applications where a 'hole' has developed filling may be the answer.
To assure a good bond for the filler it may be necessary to key into
the parent casting a bit with a sharp tool. Before attempting this
it would be a good idea to consider the wear factor of the filler.
Moglice is the standard of the re-conditioning industry. The Devitt
Machinery Co. www.moglice.com
is the maker of moglice. They do machine re-conditioning on a large
scale. However they will take the time to advise someone like me who
runs a very small shop. Get their booklet and catalog. It makes a
very interesting some night when the Red Socks are playing against
themselves and losing while the Yankees sit in the dugout and laugh!
In my case the wear on my bed was about 6" long in front of the
chuck. Old SBLs of the tool-room size usually have this condition
for 2 reasons: 1. most of the face and drill work occurs near the
chuck 2. old lathes that come to second owners have not been kept in
tool-room condition The field rep I spoke with recommended a
two-fold approach of both scrapping and filling. Had I the bread,
I'd crate the old girl off to those guys and have them do a total
face-lift! This would most probably occur 3 seconds after a squadron
of bacon flew over the house. Call these guys, the printed matter
and photos is worth it. They do some BIG stuff! Ron (12834) |
| Picture and
musings |
| I agree that
parting out to save more machines is the way to go. This way you can
keep it in the family so to speak. The thread on half-nuts intrigues
me. How difficult can making a set of half-nuts be? Not having a
picture in front of me I rely on the fuzzy memory of the critter.
Basically, (I recall) it appears as a bronze tube with wrinkles on
the ID and 2 slots on each side. You split the tube after all
machining is complete. The use of a finishing tap of the correct
size could act as a finish reamer. Available in MSC. Another idea
may be to use moglice and form a thin "shim of threads" around the
lead-screw. I personally would like to make some half-nuts just for
the hell of it. Threading ID acmes with a single point is fun. My
own problem just now is a chatter on finishing cuts. It appears very
even. I hear no apparent noise while running. I do leave the belt a
bit slack when running. There is also the problem of heating of the
front bearing when using back-gear for more then an hour. I will
explain this in more detail in a later post. Ron (15716) |
| More ideas |
| Some time ago there
was talk of using some kind of counter for the X-axis of a lathe.
May I offer a cheap and accurate substitute instead of a DRO? Simply
put, get a 2" travel dial. Place it on your way stop and put a large
knarled knob on the way stop for setting purposes. This way you can
do long or short shoulder work. I got one from MSC that functions
well. I purchased it by name brand and country of origin, federal
USA.If you can get an old one of these and have it re-built so much
the better. When your not using it on the lathe, it can be helpful
on other machines where accuracy counts. Like on a table saw. I own
a cheap 10" craftsman table saw. Got it back in '75.Though it has a
cast iron table, it is not a Delta cir. 1957. The fence is a
sheet-metal type with a spring-loaded alum "T"-head. With my travel
dial, I can get that saw to repeat to within, (your not going to
believe this!) .005.It is not time-consuming to set up and use. A
meg base or other heavy base will do. Look in your wood working tool
catalogs and you'll see they also offer this same set-up. And for
that hard to buy for shop hand that has every Norm toy, don't shop
draw. Make up a chart having 2 columns. The left column has the
number 1. On the right has half that number in decimals. Each
succeeding number is larger by 1/32 or 1/64,(if your real
ambitious!). Go as high as you wish like 12".Put this on a
legal-sized piece of card or larger. Spray with a clear finish to
make it easy to wash the blood off. So when you need to know half of
2 13/16" you'll just look to the right and find it to be 1 13/32 or
it's decimal equiv. Trust me this thing is a real time-saver. Ron
(15884) |
| New nut-cutter |
| Congrats on
threading! In my last post I neglected to mention the ditch at the
end of cut for some threading. It leaves you a place to stop while
lifting the lever and dialing the cutter away from the site. I use
my 2"travel-dial to stop for internal threading. It is my internal
eye so to speak. Works well for OD thds. as well. If you are missing
a threading dial but have reverse, leave the engage lever in place
and use the stop button and out-feed dial. You turn off the motor
while dialing out of the thread, then reverse the machine to bring
your tool back to the beginning. I must admit that the lathe is
where I do a lot of thinking. It is very relaxing to have such an
old miracle as this to solve problems with. A great place to learn
astronomy. But another comment puzzles me. Why does a saw, joiner
and sander seem incompatible with a lathe? If your married these
tools can save your life when your memory fails 'round about some
historical date, (like her birthday) To my vantage point a band saw
and drill press are missing here. Then you can build anything from
telescopes to boats. Ron (15889) |
| Lathe benches
& tool grinding |
| I guess any
material will work for a lathe stand so long as it is stable.
Materials like wood will move regardless of how tight you build it.
Because of temp. changes and such it will move about some and must
be re-checked for twist at least once a month is extreme cases. That
is why I prefer metal. The amount of wood you need to equal a steel
or iron bench is large. (I say this to start a debate). I have been
in shops where the wooden floor was 100 years old. You can tell this
up here in old New England by going down cellar and counting the
number of lolly columns holding up the machines above, then multiply
by4! But even steel has it's enemies, like temperature and soil
movement under the concrete. In my case frost heaving. Large
machines like horizontal boring mills and 36X100 CC lathes are
usually mill-righted on a special poured block of concrete and
steel. This is then isolated from the production floor and treated
like a raft. For our applications here just remember that twist and
vibration will be with you always. It is always a good idea to have
a maintenance program to check this. Always use the same spots on
the bed to check your twist. If you want more on this thread, I'll
do a separate piece on the subject. Now about tool grinding. It's
pretty easy really. CAUTION CLASS IN SESSION, you may want to skip
this part if you know this already. Start with a bench grinder that
has a smooth running wheel,6"or8" is good. Get some hard wood 3/8"
square maple or cherry stick. Cut them up in 3" pieces. Set your
grinder stage on 5 degrees. Eyeball this for now. Begin by touching
the practice piece (left side) to the face of the wheel. After you
get a concave edge, turn the blank to the left and put the same
scooped out edge to the front; only turn it 45 degrees past 90 to
achieve an 'A' shape as you look down on the blank. This is the most
basic of all tooling you'll ever encounter. A flat left side with a
concave edge, a front edge that resembles a right triangle, and now
grind the top. Place the blank so that the top of the tool faces the
wheel. It will be on it's right side. As you bring the tool to bear
on the wheel, kick the back of the tool so that you grind more off
the back then the front. A few degrees will do this. Nut'in fancy,
After all this ain't rocket science. You now have a template for
comparing when you do the real thing. The 3 angles are good enough
for most work where you will do both turning and facing of
shoulders. A lot of guys turn their tools a bit to the left so they
can face larger diameters as well. A threading tools is not much
different. The shape is more critical of course,(60 degrees) for the
sides and finish the top with a hand stone. Well gotta finish some
Xmas presents. Ron BTW, why the specific hardwood? I like the smell
of them as they burn on the wheel of course! (15919) |
| Tooling &
visible means of support |
| Been following the
base support with interest. Two things stand out: 1. Design: As in
almost anything, simple design calls for meat where it counts.
2.Materials:Metal and stone will always win out over wood. You must
begin with a lignum vita class of wood if your going to try and
compete with iron and steel. From here on, it's a matter of what you
have at hand in funds and time as to what the finished product will
look like. For stability, I choose a cast iron frame that sits on
3/4-10 studs that were set in wet cement. This way you have the
ability to have a very rigid base that your lathe sits on that
cannot move much. Then you can still adjust for 'seasonal drift'
without sacrificing strength. Many good lathes will have leveling
screws built into the main casting. In this way, the manufacturer
has provided for isolating the machine from vibration and still
keeping it level with rigid support. When I got my SBL 10" ,(a
generous gift from a friend), the first thing I did was to make
3/4-10 studs and 1/2X2X2 inch nuts. Each of 4 levelers had a
2"sq.X1/2 plate base and stud. To this I made up 2 nuts made from
the same stock. I then made a wrench from 1/4" sheet steel to do all
the fine tuning. OK so I' a tad anal. But when you have a garage
floor that likes to change zip-codes every year you act accordingly.
This system works very well. It supports the machine and allows for
change. As for tooling, I use HSS for the most part. Very little
carbide is necessary unless you do a lot of casting work or work a
lot of stainless and related bit*** material. I like HSS for its
finishing characteristics, and its ease in grinding. It is
particularly useful for insert tooling, like boring bars and milling
cutters. And if you want to try something really novel, buy a set of
diamond burrs and a diamond fret saw W/blade. Using water to drip on
the work, experiment on some HSS with Dremel hand grinder. You
should be able to put chip-breakers on lathe bits and form slotted
bits that cost a lot to buy. A polishing point of diamond
impregnated in rubber will put mirror finishes on your edges. Works
great on carbide too. Avail through lapidary suppliers who appear in
the Lapidary Journal web site,
www.lapidaryjournal.com
I call this 'crossing the street'. Since I am heavily involved with
the gem and mineral trade, I can tell you the 2 disciplines are VERY
compatible. I have used diamond polishing techniques on HSS with
excellent results. Happy chips make for long life, Ron (15947) |
| Where to put
it |
| I agree with Clive
that every lathe is somewhat straight when it leaves the factory.
Course in some cases the boat trip over can give some of 'em a real
twisted outlook on life! Ahem, however it may be said that if your
little jewel comes to you through the e-bay nursery or even 3rd
hand, there is no grrruntee it ain't a twisted sister! Try this if
your setting up for the first time. Put the lathe on a flat bubble
surface. In other words, a bench or floor that is plumb. Now shim up
any gaps that appear under the feet so that the main casting appears
to have it's feet on the ground so to speak. Now get out that $14.99
bubba stick and check the ways front and tail for twist. I'll be
very surprised if it is dead nuts. Never ran into any lathe that
didn't need some primp'in. Most of the junk I ran was far from new.
I had to put a piece of bar stock on dog and center to clean things
up after using the bubba stick first. Could be I'm just the kind to
attract all the rejects, (wifey is now reading this over my shoulder
WAP! I hate it when she does that!) OR it could be 1. mistreatment
through use or2. an un-seasoned bed. Or both. Whatever the case the
final test to be sure your creme-puff is up to spec. is to test with
a 1" bar and a dial indicator. The setup for this should appear in
many lathe books supplied by the manufacturer. Basically you take a
0 cut up at the headstock, and another one near the tailstock. Do
this after you have zeroed the tailstock with an indicator attached
to a bar chucked up to the headstock. If you kiss the stock with the
same reading you had at the head and it reads small, then the twist
is toward the operator. If you place a piece of ground stock that
has good centers in both ends, run the indicator on center the
length of the bar and note the results. Just about all lathes have a
'saddle'. The low spot used the most in front of the chuck. Unless
you plan on doing some close work near the chuck ignore it. Now as
to the title of this hear tale, 'where to put it', I'd say never in
the corner, like I have done. It's nice to at least be able to
squeeze around the machine so you can service it. About 3' around
three sides is ideal. The left side should be near a wall so you can
use the tube. HUH? Yup the tube. A Harvey cheap-shot. Actually any
shop with screw machines will often do this. They take 2" steel pipe
and drill a hole through the wall. At the drill company we used 20'
stock. The pipe is supported by an outrigger wire setup outside and
an inner sleeve that allows for stock insertion inside. When the bar
get close to the end of the machine we would pull the feeder tube
closer to the machine. To keep a very nasty condition from
happening. Like the day one of the attendants failed to do this. In
this case it was a piece of 1/2'1144 steel. The dumb kid wasn't
watching his machine, (probably snak'in on one of the girls in the
fluting shop!) The inner sleeve of #4 machine vibrated back to
far...ever see a piece of 1/2" steel flying around an 8' arc at
600RPM. Kinda gets yer attention, let alone destroying everything it
touches including the concrete floor! Noisy too! I like my 4' feeder
tube. It sticks out the shop wall and lets me work on anything I can
stuff in the bore of my SBL 10". BTW what's a heavy ten anyway. Does
it sit on the floor or is it a big babe with a boo WHAP! God I hate
it when she creeps up on me like that!? regards, Ron AKA lumpy
(15960) |
| Threading,
unsticking & polishing tool bits |
| I might interject
here about most hardware store dies. Having worked for a tap and die
factory, briefly, I can tell you most taps and dies are made from
carbon steel. Unless you know for a fact that the die you purchase
is HSS don't count on it. Most stores will only carry weekend
threading tools. They are use once cheap throw a ways. The clerks
will calmly admit that the average guy wishing to buy a tap or die
don't know what they're getting...or care. As long as they can clean
up the burrs on that head bolt they tried their damndest to wring
off. If you want to throw some threads on the end of a shaft, face
it square, g ive it a double depth chamfer. Then start the die in a
die stock that is kept square and moving by virtue of the tailstock
you cleverly put behind it. Did I say use oil? I would not use a
carbon die on any kind of tool steel. Firstly because most of the
carbon steel today is poorly made off-shore junk. Spark testing it
will only tell you the carbon content at the point of test. It does
NOT tell the whole story. Secondly, because you really need to
anneal the piece in some kind of oven over a period of hours before
machining. IMHO I'd go ahead and just single-point the piece if you
could. OR buy a carbide or better yet TinCoated dies. At least you'd
get at least one use out of the die. As for taking off a chuck be
sure it has right hand threads. Warm up the headstock and pour
diesel oil around the base of the chuck. This should accompany the
torquing with a 4' bar. Some tapping with a DEAD BLOW lead hammer to
the bar under tension should release the chuck. A lot of force at
once will damage something. Take the same force and exert it over a
period of time will not. I like the idea put forth by catboat for
final polishing of tool bits. For $20 you can get some 50,000
diamond paste in syringe form from Rio Grande at
www.cataloginmotion.com
Put some of this on that leather for a scary sharp edge on most
anything. Oh and finally. That gear shaver thread gives me ideas.
I've got a shaper with a 7" stroke I'll have to put back on line.
With the price of gears today a fellow could keep himself in single
malt scotch making gears for telescopes and lathes. Thanks for the
heads up. Ron (16016) |
| Drill grinding
& the human factor |
| Drill doctor huh?
Used one, not impressed. There are those on this list who have been
subjected to Ron's cynicism when it comes to gadgets. I was
interested in something like this rig for doing drills smaller then
3/32. After using a Dr. Doctor belonging to a friend, I decided
that:1. It was over-rated and 2. under made and over-priced. The
thing about stuff like this is that they are gadgets, not tools. Now
if you want a jig that works, either get one of those drill
sharpener rigs that stand at the side of the wheel, or make one. OR
learn to do it yourself. Even small drills of 1/16 and under can be
hand done. I taught some friends with shops how to do this. If you
clamp a 1/2" block to the grinder stage, (tip stage at some angle
like 120 off the vert.) at 59 degrees, and get a metal drill gage
form General Tool, your all set. Remembering that any cutting tool
must have the edge of cut higher then any other part of it is the
most important thing. Balancing the cutting lips so each has the
same amount of cut is the second most important thing. I even
sharpen my 2-lip end mills on a little junky 4" bench grinder from
Miller-Falls. It has no balls to it so it's easy to stall, perfect
for hi carbon drills. The wheel must be trued up with a star or
diamond sharpener. A course wheel will do, but a fine wheel on the
opposite side gives the tool a finer edge. By laying the drill
against the block and stage you bring the tool up to the spinning
wheel and just touch it. Look at it with a loupe. You will see quite
clearly where the grind is. By using the drill gage you will also
see how close to center the drill-point is. Use a crummy 1/4" drill
for practice until you get the feel of it. I encourage my students
to begin by just grinding or touching the last 1/16 of the lip to
the wheel. Rolling it takes more practice. Advanced practice will
yield a drill that looks 'factory'. Everything behind the edge is
unimportant at this stage. For now just joint your edge so they are
centered, higher then the heel of the drill, and sharp. Unless you
have a handicap, you don't need a Dr. Drill. My own physician always
warns me, "Ron stay away from doctors"(..guess I run to many of 'em
off!) Want more, just ask. Ron I prefer to do many of these things
by hand and eye. It is faster and builds confidence...not to mention
a bit of pride in workmanship. Something this country lacks, but
seems to be willing to import. (16173) |
| Drill
sharpening & some oil ideas |
| We last left our
intrepid hero in front of the grinder scratching his head. Meanwhile
Snidely Whiplash has tied 'lil Nell to the tracks. OOPS! Turn page!
Let my clean up a few details on drill grinding. First get a picture
of a drill tip. You will see it has lips and heels. Like sweet
little Nell the lips are always higher then her heels. And lips
always get more attention..as they should. (He now looks at his
book) If you take a 1/2" drill and hold it to your eye, you'll
notice how the factory sharpened it. Most drills will look like they
have a smiley-face grind to them. This is what I call a minimum
grind. Not much clearance and hard to replicate. My explanation for
this is mass production. They set their machine for all drill sizes
and let it go thinking that the bonehead consumer will probably
sharpen it once and throw it away. Boy are we dumb! Look at your
drill and if it has a slight incline from Nells heel to her lip, you
got a drill that is properly ground. This shape is the simplest to
create and maintain. For most metal and wood applications, it is
ideal. In my last letter I used 10 degrees as a ballpark figure for
this angle. Chapmans "Workshop Technology" uses 12 degrees. Go with
this figure. To check for center of cutting edges, grind lips and
ink over with magic marker. As it dries, place in drill press and
drill in some metal. Just enough to show up any high spots on ink.
Sounds time-consuming but it ain't. Buy doing this you get a very
accurate picture of what your doing. Now why is this important? It's
just a hole right? A hole that can be off the mark, to big, or cause
little Nell much discomfort...and plastic surgery, (imagine the
lawsuits!!) It is possible to screw up a drill or a work-piece
because your to darn lazy to sharpen a drill the right way. It takes
less time to do it correctly the first time then to do it wrong and
do it twice. The ink will rub off the high side of the drill. You
can also make a little test block with a new drill and use this as a
gage. Instead of taking off metal the test block will be dimpled
enough to just rub off the ink. A bit faster then drilling. Once
you've managed to get a good point and rake angle, you can stone the
very edge of the lip with a fine India stone. One or 2 licks only.
Until you master all the other kinks in drill sharpening, jointing
is not important. Or web thinning for that matter. Later I will go
into this if there is still anyone left awake. Now about oiling.
About 3 beers into last night our little group ('Ol Farts Society)
Come up with this cutey. If you want to purge a system, as in lathe
HS bearings why not just flood them? Stuffing some tubing into the
cups and let a quart of whatever you think is best flow in
IV-style,( gravity-feed) until it flows clear. Then replacement of
new oil and your done. Works in car engines and grease fittings. In
my own shop I grease all my equipment this way. Haven't had to
replace any bearings as yet (of course about now all my machines
just heard that and will all fall apart!) Anyway it sounded like a
great idea last nite. Ron (16202) |
| Ron, The IV flood
into the bearing might work if the lathe has something other than
ancient oil (shellac) in the resrvoirs to change the oil but it
doesn't remove the particles which should have settled to the
bottom. The apron has a drain plug and the 'Heavy 10' and the like
have drain plugs for the spindle bearings. These may flush out with
that method with the plugs removed. Not sure how it might work on
the 9 and 10K spindle. JP (16206) |
| Recycling
tools |
| Most of us here
tend to be cheap. Why buy it if it can be made. This keeps our
wallet a bit more full and we have an excuse to go out into our
domain and create. "See honey? I took this old tool and made a new
one. Wad da ya mean it's 10:30 at nite?" Stick with me boys an I'll
save your marriage LOL! Now back to our show. I got this idea from
Harvey. He never threw out anything if it was any kind of useful.
Like the tapers on old tools. Most of them were either high carbon
or HSS. Broken taper shanks were an excuse to make new tooling that
was very accurate. Try this one: 1.Take broken shank drill and cut
it off square at the taper. Even HSS should be soft enough down
there to cut with carbide. Most drills will be hardest at the flutes
then the shank. If the taper is not to dinged up put it in the
t-stock. Of course you should find tapers that fit your lathe to
begin with. Now face off the taper using an end mill or spot-facer
held in h-stock chuck. Then center-drill it. Your t-stock should be
aligned to the h-stock before you began. After center-drilling,
choose a drill or center-drill that you want to mount in this taper
shank. You will probably drill and ream the hole for a good fit.
Because your building a center-drill holder that will be the most
accurate thing on the market. A number 2 or #3 c-drill held in an
old taper will not wander when you use it. The drill is set far
enough into it's hole so that only the last 3/8" pokes out. After
drilling either ream or lap the hole so it fits the c-drill or
whatever you want snugly. To keep it from turning, finish the job
with a 10-32 button-head socket-screw that is screwed down on to the
flat you so cleverly ground on the tool. I use my taper c-drill all
the time. My grandfather made it in 1950 for his lathe. Harvey
showed me this kink when we worked together. Guess where HE learned
it...yup, from my grand dad! Get several sizes of c-drills done up
in this fashion. You can probably get broken ones at flee markets or
g-sales for next to nothing. Our education system in this country is
making gods out of men who know this kind of art. You won't even
find a picture of a lathe in any textbook or library in most
schools. OOPS! off-topic! Another use for old tapers would be an
indicator holder. A drilled hole with a thumb-screw makes a dandy
rig for dial work in the lathe. 2.Now for small work: The larger
taper you found in someone's junk-box happens to fit your h-stock
bore. It has enough meat on it for a real brag job. Find a 1/2 drill
chuck. Better yet a 0-5/8 CAP drill chuck. If it has a shank that
will not fit the bore, remove it. Chucks are either screwed or
tapered to their shanks. Thread or taper-cut the taper you just put
in the bore. Then install the chuck on this. Now you have a chuck
for small work. And believe me this little cutey will wow them the
next time a mower part for a neighbor are in sore need. If you turn
and finish it correctly, it'll last a lifetime. You will want to
make a knockout bar wit got a piece of brass or lead on the end.
Most old lathes had them. I can still turn a .030 pin from 1/4
stainless on mine. Ron (16277) |
| Today's kink |
| Seems we all have
local problems. If you want my take your s and how I handle mine
e-mail me off-list. Meantime I learned the beauty of lacquer thinner
as a releasing agent for a 6-32 set-screw frozen in alum. Simply
put, this thing was jammed in with corrosion and rock dust. I
squirted some L-thinner and waited a minute. Then backed out the
screw. Worked like a champ. If ya get a chance to watch the History
Channel, look for the history of steel. It seems to touch on recent
postings. Another member had pointed out that he feels like a
custodian of a dying art. My paraphrasing. He is. You are. Comes
with the lathe. Pure fascination of the simplistic in a complex
world. After the lights go out we can still make things if we have
some kind of movement. Water or solar. If we had that the people who
think they got us under their thumb...won't. See that's the trick
here. If you can control what comes out of the ground, you have
absolute control over it. Like iron and food. The 2 most important
trades in the post stone-age world. Farming and black-smithing. The
pencil-pushers think influence drives the planet. Can't influence if
your stuck with a horse and no shoes, hunger and no food. Learn that
lathe man. Teach your child that lathe. It is after all a point of
departure. Ron (16326) |
| On another list
someone mentioned using Hoppe #9 bore cleaner to free up frozen
metal. Just another idea for anyone that needs it. JP (16327) |
| Cutting off |
| Now about cut-off
methods. There are 2 that I know of, melting and burning or burning
and melting. The mention of using a band saw calls to mind the
procedure for friction sawing. When I was in aero-space, (P W
vending shop), we would friction-saw titanium. We would take a new
blade and saw a rock til hell wouldn't have it. Then we would crank
her up full throttle and use what was left to cut with. Sounds a bit
drastic but it works. The other method is to use the cut-off wheel
that uses vitrified stone particles bonded together. I use an
8"X1/8" cut-off wheel in my grinder. But before I do any c/o work, I
gently remove the stage what come wit the grinder and toss it. I
then make a new stage that can be adjusted for any type of grinding
or c/o work. I use 2"X2"X1/4" angle iron. Foot and post welded
together. The post is slotted to accept the stage that has an arm
that is slotted between the two. This articulation gives me lots of
adjustment. The 3X2 inch stage lets me mount any c/o jig I need. One
gizmo I dreamed up is a piece of angle iron with a series of tapped
holes in it. And a small rail underneath for guiding. It is a bolt
machine-screw cutter. You run the bolt or screw thru the hole for
the right length, then push it into the c/o wheel. Then un-screw it.
Presto! flat end of screw that only needs a wire wheel and a bit of
filing. Forming lathe bits is easy on the c/o wheel. Set the stage
to 3 degrees and push the tool at a 30 degree angle. After the angle
is made, use the wheel to hollow grind all cutting faces. Then move
to your left wheel that has a fine grit and finish. It too has the
same kind of stage set at the same angle. With this set-up you can
dress a tool in about a minute. For a keen edge, lay a stone (fine
India) flat on the tool face and give it about 3 swipes. This is
called jointing if your a woodworker. The whole rig is indispensable
to me. Just remember to keep your wheels in trim so you got no
run-out. The best way to do this is to make a sharpener from a
mounted diamond that is made for this purpose. The single 1/4 carat
or cluster diamond dressers in MSC or any lapidary supply house will
do. Make up a wood or alum holder that slides across the stage and
wheel. It should be clamped so that it can't be shoved away from the
wheel. This way the wheel is dead true and square to the stage.
Something you want if:1. you don't want to screw up your motor
bearings, and 2.lets you do squaring off work on small pieces of
metal using the front edge and a small 'T'-square arrangement. Boy
can I run my gator or what!! Cut-off wheels are a real time-saver
around the shop. When you can control your tooling, you can really
control your shop. Ron (16683) |
| Fixture |
| I made a joiner
knife sharpening jig today. Last time I sharpened my knives was back
in Florida, circa 1981.Since the square stock I originally cut up
would not work, I chose a piece of 1 3/8" round stock alum. I had no
jig to hold a square piece properly at a 35 degree angle. You need
to cut a slot that has screws in it to hold the blade. So I cut the
slot the length of the piece, down the middle. Off-set the slot and
put tapped holes,10-32 along the length. Then just tilted the
fixture the needed 35 degrees, and ground the blades on my mill.
Worked out real well. Sometimes the obvious bites you where you sit!
regards, Ron (16963) |
| Setting
'tails', a shop story |
| It is probably
obvious to everyone that when setting your tail stock, use a dial
indicator to measure your progress of movement. Also, I missed the
part where you should let up on the clamping wrench a bit when
moving the tail stock right or left. I have noticed that your
position will jump to much if this is not done. When I move my tail
stock around, I always use a mag base and D.I. Pick a spot on the
T.S. that is flat and out of the way of swinging wrenches. A 1"
travel-dial is great for this purpose. Play around with the wrenches
and binder clamp to see what moves the dial, (hence the tail stock).
Once you have toured the pitfalls, go to work using the methods
formerly explained. With the D.I. and test bar, you can get the
correct position very close. If there is a lot of wear on the bed,
(IOW does it 'snake' a bit?), make up a map of set-over points for
future reference. Then if you need to set the TS at a particular
point, you know just how much to set over. OK, I've been saving this
one for a time when cabin fever begins... A few years back I worked
for a mill work shop. We did everything from inlaid floors to spiral
stair-cases. The owner of the shop is an old wizard of wood with a
legendary sense of wicked-good humor To wit, the following tale:
George was in the mill one day setting up a shaper. The knives were
quite large, 'bout 1/2 lb. each. The spindle held the cutters
between slotted collars so that the next event isn't 'suppose' to
occur. Mitch, his son-in-law came over to say he was going to the
bank and left. George uses a stout plank of oak as a shield between
the spindle and himself. Keep in mind the spindle is 1 1/2" dia.
with a Large nut. Well, George tightens up the Jesus nut, puts the
shield in place, and fires up the 3-horse motor...The first knife
went into orbit at time-zero +1 second. As it sliced the steam pipe
40ft away, it created a nice humidifying action for the glue-bench.
The second knife departed at time-zero+1.5 sec, slicing its way
through a 2" oak plank and ricocheted off Georges tummy. Of course
George never gets excited over much and this event was no exception.
He did notice some blood on his shirt and just put a compress on it.
He found the second knife sticking in the far wall on the other side
of the room. About that time Mitch comes back and sees George
working the knife out of the wall (with a pry-bar!) "George,knife
come loose?" Yes he replied." It bounced off me and landed in the
wall". Having recovered the knife, he drove himself over the ER to
have the 'cut' looked at. Entering the room, he began explaining his
situation to the nurse: George: "I cut myself a bit from a shaper
knife.." nurse: "oh don't worry, we have seen it all in here"
George: "There were 2 of them each a half lb. apiece". nurse: "Well
let's see what we got here". She begins to remove the compress.
George: We found the first knife but are still looking for..."At
this point the nurse finally tunes into what George is saying while
getting her first look at the wound. ...and faints dead away. Did I
mention that George has an evil sense of humor? The doctor put in 40
stitches's on the inside and half again as much on the closing.
George of course went back to work, and took 2 aspirin. These shaper
knives are 1/2"X5"X3".They move at 5,000+rpm.Watching them in action
gives you considerable respect for moving steel. This pales in
comparison to George and his sense of adventure...and fishing a
nurse but good. But it's a hell of a way to set the hook eh!? End of
story. Ron (17063) |
| Old age |
| Old age and
treachery will always overcome youth and skill. I heard that one
from a medieval re-enactment group called the Society for Creative
Anachronisms, the SCA. My comments in 'closer tolerance' post were
aimed at the banned Tom Troll, only. As for threading, a few tips of
tips: -Spring cuts can be your best friend IF you use them for
clean-up -If your new at threading ,brush on some layout dye to see
your progress better. -Keep a piece of 1/2"X 4" yellow brass round
stock at your lathe. You will use it for taking the 'chip weld' off
your tool. Place on the tip of the tool and just rock and roll. It
also is the best file cleaner. Best one end with a ball-peen hammer
to mushroom an edge. -Rather then wear out a slip-stick figuring out
how much a compound feed screw moves, just put an indicator on it
and see exactly what it does. -Most threading dials I have used are
set up as follows, Even threads, any line or any even number, odd
threads, odd numbers, multiple threads,1 number. -Rough out your
threads until you have a v form with a bit of flat top to it. Then
take the tool out and sharpen it up. Pick up the thread as explained
by another old hand, and finish -As for how deep, make some
adjustable threading go-no go gages. Cheap ones can be had by sawing
1 side of off the shelf hex nuts and springing them in a vise until
you get the feel you want. A screw-driver will open them, the vise
closes them. -Clean-up and honing can be done fairly accurately. Get
a 3-corner file and some silcon/car. #220,#600 grit. Going over a
thread and spot honing in forward and reverse works pretty well. Not
much is said for filing on this page so far. Maybe I'll write
something about it. regards, Ron I do a lot of stuff by feel.
Probably the most important sense you can learn in this art form.
(17177) |
| Something Ron left
out on filing is the use of thread pitch files to finish/cleanup
threads that are just slightly tight or rough rather than try and
reset the part in the machine for another cleanup pass. Your best
friend is a gauge of some kind to check the thread fit with before
removing the part from the machine as several have already pointed
out. But if you do take it out and have a difficult time of syncing
it again a pitch file while a very cheap item can be your very best
friend. Last month we had a rejection on some parts that fit our
certified gauges fine but were rough in our customers gauges, We
fixed 25,000 parts with the pitch files at about a half minute or
less per part. JWE (17178) |
| Threading and
scraping by |
| Some good stuff
here. Got to try that kink on threading. Never thought of zeroing
the compound and 'bore-shooting. Ought to be fun. We are all
children here. Some of us have more wrinkles then others is all. Of
course HOW we got them is a matter of shall we say history? G There
is some good reading here as I said. This old vs young has been a
sore for a long time. Mine at least. And I feel it very topical.
Getting a kid to want to learn is at the very core of education. We
ought to come up with and "Adventures In Machine Shop" computer
game. There is an old book on my library shelf called, "On the
Battle-front of Engineering", by Bond. The author came up with
stories of bridge-building and such. While your engrossed in the
plots, your getting on-the-job engineering. Now a quick primer in
filing. First of all there is keeping them clean. I use brass
brushes and a piece of brass round stock. The brush gets most of the
crud. The bar gets the rest without dulling the teeth. Old files can
be renewed by immersing in muriatic acid. Use a tall glass jar. If
you can find an old canning jar with a glass /bail lid, that ought
to do. NEVER use alum vessels. They tend to make the day exciting.
Tie the file tangs with copper wire. I use the ground from 12-3
house wire. Let 'em cook for about 3 days. Rinse well with water
followed by oil. Then, believe it or not, rub them down with saw
dust. This actually removes most of the oil. The result is a clean
sharp file with a nice gun-metal blue tint. I make my own handles on
the lathe. Turn the blank and drill a tapered hole for the tang. No
gots tapered drill? No problem. Trace the tang on a piece of paper,
then match the lines with 3 drills. This will give you enough meat
to grab the tang in the hole. Of course you already have a profile
for the handle drawn on a piece of light cardboard. Take a file that
has a handle on it an carefully grind the tip for a 70 degree angle
w/1" radius. Now you put the blank ,(with a half-inch waste at the
pummel) in the chuck or driving spur. A live/dead center in the T/S.Use
the tool post and bar for a tool rest. Keep tool post close to work.
Finish the job with #220,and friction polish with boiled linseed oil
and a paper towel. Being VERY careful not to go spinning with the
handle. Some guys burn their holes in the handle. It works but use a
separate tool for this. Otherwise you may loose the temper in your
file. A tool with no temper IS a dull boy! As to how to file. On
round stock, use a single-stroke, lift off and repeat on the
opposite side of the file. OK so it's slower then death...ya got a
hot date here? This is SUPPOSE to be fun. Besides she has a 'Honey
Dew list' the size of the Queen Mary II waiting to grab you!
Single-stroking assures you will not gall the surface. After each
pass, clean the file and repeat. NEVER use chalk. Waste of time. I
prefer single-cut mill-flat files for the best finish. I keep 1 new
file for real fussy work. Three-cornered files are great for
cleaning bolts on lawn-mowers, and anything that is just maintenance
work. Quarter-round double-cuts are good for bad crud/rust
clean-ups. They are good for rough work and wood filing. A set of
small Swiss needle-files are very handy to have. I use the 3-corners
for tuning up single-point work. Keep your files in a rack that
doesn't allow then to touch each other. A wood rack is ideal. If you
use a favorite file on the lathe, make a small box that closely fits
the bed. A 2 level job keeps your bed brush, oil-can, and file off
the bed and out of the way. NEVER lay a file on the bed! Also as
pointed out in another post, always use files what got handles on 'em.
Keep strips of silicon carbide wet or dry at hand,(220 600). Use
these with a mill flat for fine finishing. Wrap about a inch around
the tip and use some mineral spirits on the paper. Again, use the
single stroke method. Observe the paper. When it looks like it's got
some build-up toss it for a new piece. For a cross-hatched pattern,
use a piece of 1"X6" #600grit.At slow speed carefully pinch the
paper to the work and move back and forth. The result will be a
honed finish. In bench-work, most of the same rules apply. Long
pieces are draw-filed by holding the tool by the ends and draw the
file towards you. Some guys will angle their files a bit,or move
them to one side as they draw. You can get a faster cut this way.
Always use a mechanics vise NOT a wood vise for metal-working. Flat
pieces of metal with scale on them should be scraped first. A slight
angle on the end of a file will take off this very hard scale. A
double-cut followed by a mill-flat file will give a good surface.
Hardwood blocks can be used against the work to steady a flattening
cut. Protect the work from jaw-marks with alum pads made of 1/16"
sheet metal. Thin pieces of sheet-metal can be squared using a
mill-flat and 2 pieces of hardwood blocking. Put the metal between
the wood with the layout line barely visible. The blocks assure a
good, flat edge. OK I'll shut-up now. As an old schooler, I believe
in hand work. Prior to the mill, ALL millwork was done by chisels,
files, and old farts with incredible hand work. regards, Ron BTW A
sink cut-out from a granite-top counter and some wet or dry sand
paper will get your straight-edge dead true. Spray the paper(s) with
water. Put them on the surface plate and move the straight-edge back
and forth. Check your progress on the same plate. You'll get a real
good tool Plate $50 sand-paper $4 experience, as good as you make it
I can here it now..."Gee honey, you'll get your granite counter and
I'll get that surface-plate I always wanted" (17216) |
| Steady boy
steady |
| Now back to the
Walt Steady Show. My own limited experience of steady rests has me
believing roller bearings instead of brass or bronze fingers are
better. The problem with brass ends is contamination, and poor
surface finish. Even if you carefully clean the area of contact, it
will degrade again. If all you want to do is put a center hole in a
piece of long work, a rub type steady is fine. Otherwise I'd
re-build the tool with sealed bearings. Get some brass and make
bushings between bolt and inside race. Leave enough flange for the
bolt head to tighten against without binding the bearing. Use SEALED
bearings. I don't know the function of your rig Walt. Having only
used either rub or roller types. It sounds like somebody may have
used it for a special job, or was in the process of re-building the
whole thing. A good friend and I once built a steady out of some 1"
jig plate. We used his mill with a ro-tab to profile shape and bore
the center. Since it was used as an occasional tool for centering,
we used brass plumbers plugs screwed to the ends of 1/2"-20 thd.
rod. For what it does for me now, (came with the lathe) it works
fine. If you use a rub steady, be sure the surface of contact is
clean and free of bumps and pits. The mill surface can translate to
the tool, with obvious results. Ron (17304) |
| Put her in
grandma |
| Duane got it right.
First thing I do when working with nasty stuff is back off. This
wisdom falls off all modern, gotta have it now mind-sets. The thing
is you don't gotta have it now! But Ron, this isn't reality!! The
Chinese are beating the door down. If we don't keep up, they'll
swarm all over us!...so let 'em. Any plant I ever worked for had one
of these guys. Usually some MBA from Slippery Rock Mental College
that majored in pencil-neck. I have a sign that hung over my work
area, "THE MORE YOU WATCH THE LESS I WORK". After a while they all
left and I got their precious widgets to them safely, in my time. I
work one way, carefully and zero scrap. In 30 years I never had a
part bounce on me. Slower then death, but I always got it there. The
rule of thumb on any material in the shop is the tougher and harder,
the slower and smarter. Hell, running a drill to fast in copper will
work-harden it in 2 seconds! I run any stainless slower then
anything else and use sulphur, black thread-cutting oil. Can't say
enough about this stuff. It's probably got enough trace elements to
swoon a boat-load of Green-Peace'ers, but it works. This
labor-saving B/S never did impress me much. Back in the '20s there
were all kinds of gadgets designed to give mother a lift and have
dad home from the plant a little earlier. Poppycock! What did dad do
with all that free time...? Right, go out and sell Amway for extra
money of course. Not go on hikes, or take in an art gallery opening,
or spend time with his family. Machine shop today is what we use to
call an ulcer-mill. It is kinda like re-arranging your stamp
collection in a pit-bull rally. Everybody is trying to out-produce
the guy next to them so he looks good and you look bad. Tell me
THAT'S good for community relations. WE ARE NOT YOUR ENEMY. The real
enemy is the first idiot who thinks coercion and corner-cutting are
motivation tools towards kinder, gentler greed. So the next time
someone saddles up to you with a stop-watch, be it boss or customer.
Remember what I use on tough material. Use slower speed and black
cutting oil...and make sure you put them in head-first! Ron (17336) |
| Filing, the
conclusion |
| Hi space fans,
...when we last left our intrepid hero, chips were falling where
they may ! Ummm, sorry, wrong script. So far everything I've said
about filing can be found in most mainstream books. Now for some
stuff they don't tell you. File steel as we know has a certain
amount of carbon in it. This makes it ideal for a bit of
tool-making. I go to garage sales and scrounge up all the old files
usually found at the bottom of a box marked tools. No one bothers to
look that hard, and the seller practically gives them away. For good
tool steel, you can't beat an old file. It has about 1.1% to 1.5%
carbon in it. You can make anything from scrapers to chisels, to
knives. Any small item that you can fit on the file will work. See
the neat thing about carbon steel is it's accessibility to the
garage machinist. By first tossing it in the bar-b-que, (hey dad why
is there a file in my steak?) you soften it for machining. Now you
can turn it or mill it. Drill it or tap it. The big files of course
allow you to do larger projects. Once the part is made, it's time to
re-harden it. By now you have a nice pile of refractory bricks, a
20gal. propane bottle, and a gas ring. All this can be had locally.
Regular red brick can be substituted for fire brick. The idea is to
build a small heat-treating oven with a small stage to put the work
on. A piece of very heavy hardware cloth that can withstand hi temps
should be fine. Make a sheet metal door that you can cover the
chamber with. The gas ring is at the bottom of the oven. This is a
very crude rig designed to heat treat your first part in. Hopefully
it will work well enough for you to want to build something a bit
more useful. No matter, fire that sucker up. While the oven is
getting up, go fill a 5 gal. metal pail with a 10% solution of
brine. Use KOSHER rock salt. Don't ask why kosher it works better.
This is just as good as quenching oil for carbon steels. And
non-flammable. The reason for the salt is to make the water wetter.
When you have all this together, place the piece in the oven and
watch the color. When it gets bright cherry red, leave it there for
a minute. Now quickly remove the article from the oven and quench.
If your making a piece that has a long axis, drop it in the water
vertically. This keeps the warp-factor down. Once it is cool, lower
the flame in the oven for temper. For a first attempt, look for a
straw color. Carefully look at the piece for color change. It
doesn't take long for it to go purple. Don't let this happen or
you'll have to start all over again. As soon as you get that pale
yellow straw, remove it to the open air. Your tool now has tough as
well as hard. To alter the shape of a file, or to make rifflers,
begin as before. Anneal the piece and grind or bend whatever shape
you want. Heat treat in the same manner. IN GENERAL, file steel is
the safest way to tool making. It is fairly forgiving stuff to work,
it's cheap, and very reliable. I make all my specialty tools from
old files. New files can work provided they meet the drop test. If
they hit the floor, (concrete) and don't break, buy it...or claim
palsy to the clerk, he'll understand! Make a set of die-makers
rifflers. These flat s-shaped files can do some wonderful work on
anything they can cut. The set you make will be better then what you
can buy. They will also be made in America...a rarity. Ron (17362) |
| Real axis |
| OK here's a head
scratcher. With all the talk about bearing wear, has anyone given it
much thought about exactly WHERE your true axis is? -The belt pulls
tension towards whatever driving source there is. -The tool forces
the spindle towards the least resistance -The tool will also tend to
force the work up as well. If you look at the headstock from the
tail end of the bed, your spindle will be at a 2 o'clock position
under load. This means that at any time the tool is cutting, the
spindle is touching a very small portion of bronze/balls/rollers. So
it would seem that the true axis is not the same as the 'working
axis', or the 'resting axis'. How then can the operator take
advantage of this developing phenomena? Another point to ponder.
Even though your lathe has a passive lube system, such as a
reservoir, bearing wear is at it's greatest when you first turn it
on. According to Chapman's "Workshop Technology" a slight vacuum
occurs when a shaft and journal are at rest for a while. Though
there is a tiny bit of oil present, it ain't much. That is why an
oil with good lubricity is so important. Machines with oil pumps and
filters are far superior in lubricating then passive oilers. Makes
ya wanna grab an old 289 oil pump and hook it up huh? Better still,
just use a good spindle oil. I add oil when my SB-10 is up and
running. I don't care if she leaks. The oil is always fresh and
clean. I'm going to file some hand saws now. Very relaxing thing to
do. Ron (17382) |
| Short sheet
metal course |
| If you want to try
your hand at cutting and bending sheet metal, try this: Start with
some .032 alum. roof flashing. Scale the size of what you want. In
the event whereby you have the actual piece to be duplicated, make
up a folding mandrel out of a 2X4 stud. If your shooting from the
hip, just make the mandrel to what you think it should look like. If
you don't have a shear, place a piece of flashing between 2 pieces
of 1/2" plywood. Clamp the sandwich so that the edges are flush to
each other. With the pieces clamped, draw out your flat pattern. Now
take this to any saw that has an 18 TPI blade, (IOW a fine tooth)
and saw this out. The thin alum will cut nicely between the wood,
leaving a clean edge. Now take your work and bend it over the block.
Since this is your first attempt at a simple 'U' shape, leave the
legs a bit long. A block and hammer will give a nice bend over the
form. That was the practice round. If you laid out the sheet metal
prior to cutting, you probably put in the bend lines as well. Note
that if you tried to bend along these lines without taking the bend
allowance into consideration, the inside width will be short.
Without a bend allowance/bend deduction chart, take some strip from
your sheet and find the true figure by trial and error. There are
charts and formulas that accurately predict these allowances.
Actually I have such a book...somewhere. Once you get the hang of
it, go for the real deal. Make the part for your cross-feed screw
cover. Flashing isn't boiler-plate, but it'll look nice and keep the
screw protected. If you want something a bit stronger, make 2 pieces
that fit inside each other. Then glue them together. This exercise
is for the garage beginner. Guys with sheet metal brakes are worlds
ahead of the rest of us. If you do want to work in sheet metal a bit
more, get a Beverly open-throat shear. These things are a wonder.
After spiking it to a hardwood chopping block the gear actuated jaws
cleanly shear through 1/16" alum or .050 galvy steel. You can cut a
straight line or curves. Guys who do body work or knightly armor
have offered generous sums for my shear. I won't sell.But you may
find an old one if you look. The company is out of business I'm
told. But this may be in error. Go to
www.thomasregister.com
and see what you may find. In the north country, this thing is
indispensable for rocker-panel repair. I'll go look for that book
now. It is a hand-made text that is all you need to know about
precision sheet metal. Ron (17431) |
| Ron, the bend
allowance is a function of the radius to thickness ratio. You can
figure 44% to 50% of the thickness for a 90 degree bend in aluminum.
You will have more error from hammer bending over softwood than you
will by ignoring the specific bend allowance. Using a soft face
hammer over the outside of angle iron works better. The critical
part is you have to tightly clamp the reference flat to the angle,
use 50% thickness as a bend allowance. You also have to figure the
bend radius in as well. For aluminum flashing you can cut it on a
paper cutter much easier. Don't mean to burst your bubble but I do a
lot of sheetmetal design professionally. JP (17445) |
| A good belt
keeps you tight |
| Most old farts will
swear by flat leather belts. The one that drove the Edison Dynamo
was a whopping 6" wide and probably 20' long. The shivs were very
shiny. Sometimes they would slip and all the lights would begin to
dim. I would get my trusty can of belt dressing and give her a
squirt. Had to be careful though. That belt would grab and peg the
amp meter! My limited experience with belting tells me to treat it
like it was still on the cow. Leather needs to be nourished.
Otherwise it may split and crack. Supple works. First thing to do is
lightly scrape the working surface. Use a 3-corner scraper of pocket
knife. All you want to do is take off the accumulated crud. And
there will be some. Don't get radical, just clean enough to feel
some roughness. Check out a supply house or even SBL for belt
cleaning products. I have never had to use them, but your
circumstances may be different. Degrease the pulley system with any
solvent. I use lacquer thinner. This next step is a bit
controversial. With the pulley turning, rub the surface with sil/con
#600.Use a cross-hatch pattern. Do this very lightly. And only if
the other tips fail to work. Now, re-assemble the belt. Inspect the
hinge wire and replace as necessary. With the machine running, spray
on the belt dressing. Don't over do it. If the belt is clean, that
should do it. I have seen those belts you put together. I hear they
work well though I'm not sure how well they work on a flat pulley. I
would rather have a belt system then a roller chain. When I was
working for that drill company, we had a big screw machine with a 6"
wide roller chain drive. Actually it was a gang of chains that wide.
One day while it was running, something in the system let go. The
results inspired a TV show hosted by some pushy English broad.
Seeing that kind of shrapnel flying about confirms your suspicions
that the devil really exists. Always slack your belts when not
running any equipment. Ron (17839) |
| Recovering
from the broken tap |
| How to extract a
busted tap...good luck! First of all NEVER BEAT ON IT! This
automatically raises blood pressure. secondly, go buy a good set of
tap extractors from a place like MSC. If you have never seen these
little wonders, they have a handle attached to some small hard
wires. A collar slips over them as you slide the wires into the
hole. Oil and some very gentle twisting usually gets the tap out. I
find cast iron the easiest material to recover a broken tap from.
That may not help though. You have wedged the HSS further into the
material. No amount of pounding will make it better. I'd fill in the
hole with devcon and leave the grave un-marked. Ron(17897) |
| Making a
rocker |
| You'll probably be
thinking, he's off his rocker here. Try this. Find a thick enough
file at some g-sale. A farriers rasp will do. Throw it in a wood
fire to cherry it up, (annealing that is). Grind the bottom to the
desired arc using a template you cleverly made from the t-post
flange. Leave the teeth intact for the top. Now re-harden with same
fire. Cherry it up for 5 minutes and quench in 2 gal.of water with
1/2 cup rock-salt added. Use kosher salt it's almost Passover! When
cool, re-heat using gas ring on camp stove or kitchen range, it is
wise to use a bushy flame. Pass over flame and look for a light to
medium straw color. Allow to cool. You now have a tough rocker that
will hold anything you put on it. Pretty simple huh? I love old
files. The steel is great for projects like this. Ron (18000) |
| Knarling |
| In shops I worked
in this operation was carried out on non-ferrous metals like brass
and alum. I usually ran at 200rpm+.The tool was either a box tool or
a clam type. In both cases all the pressure was on the part, NOT the
headstock bearings. I cannot stress this enough. Knarling is IMHO
the worst thing you can do to a lathe. If you do not have a clam
type tool, at least run the operation using a dead center for
support. I have done knarling using air pressure rather then oil
when working alum. Because of its galling tendencies, the cutters
must be kept clean. In another book I have on shop practice, the
author says to jam that sucker into the work. Different school of
thought you might say. The only time I knarl is if I'm making a knob
out of plastic. My old SBL does not need that kind of pressure on
it's forward bearing. My dad had a milling attachment for his old
Atlas 6" lathe. It was fine for making small parts no larger then
2"X2"(if that). I consider any milling attachment on a lathe to be
for light work only. It is possible to do small die sets so long as
you have lots of time and some sharp cutters. I have done jig-button
work on a face-plate or 4-Jaw.Just as long as you keep in mind that
it is a lathe, not a V-mill. A friend of mine owns a Smithy. It
looks like a lathe trying to evolve into a mill on drugs. You can't
single-point thread on it. And it doesn't have enough room to put
any kind of rotab or vise with any usefulness. It is more drill
press then anything else. Like a 4X4 with velour seats, or a
gold-plated computer, it just leaves you stuck in a more remote
spot. BUT in fairness to those who are starting out, these
entry-level lathes and mills do have a niche in the trade.
Gun-smiths with little room for big equipment like Smithy's for
their ability to do both lathe and mill work. If a school shop has
only enough money to stock the shop with this level of equipment,
fine. Just do anything to put a kid in an apron and get him/her
thinking while doing! Ron (18270) |
| 3vs4 jaws |
| Opinions will very
on this subject. My opinion is that a 3-jaw Buck with jaws that are
reversible and can be trammed to zero is your best choice. That is
what I use. The actual holding element of the chuck can be zeroed to
compensate for irregularities in the lathe. The reversible jaws
allow you to hold large diameter work such as a 4" piece of round
plate. The 4-jaw does let you hold square or round work. It's
preciseness depends on how good you are, (and patient) with an
indicator. If I were a retiree, I would choose the 3-jaw.I don't
think I want to take that much time fooling around with a dial
indicator if all I'm doing is making a spacer. I use my 3-jaw
adjustable every day and only need to check it once a month. My
usual readings on inspection are .001 total indicator readings. One
other point on 4-jaws.They may hold square stock, and can be set
finer for run-out, but if they are not new, the jaws can cock a bit.
See most 4-jaws are merely a big set-screw that moves a jaw with
partial threads on the back. There is much more slop to them if they
are worn or worse yet off-shore. Plaza will give you good advice.
You get what you pay for. IMHO, the off-shore adds it's own grief to
the price. With the exception of Polish or other European tooling. I
find it very good! Ron (18470) |
| Chucking it |
| In my many posts, I
neglected to mention soft jaws. A soft jaw set can fit almost any
chuck. That is provided the existing jaws have threaded holes in
them. Briefly, a soft jaw is a cheap refit. The set of 3 or 4 jaws
are soft enough to be bored. The bottom of each jaw is milled to fit
whatever brand of chuck you may have. The only requirement is that
your chuck has jaws that can be taken off by unbolting them from the
scroll jaws. I believe you could even replace the scroll jaws with
new ones that will except soft jaws. The advantages out-weigh the
expense. Soft jaws as I said can be bored. You can put a set on and
in 1 operation, Bore them dead zero for holding bar stock. Just take
a piece of short bar end that has been turned and clamp it on the
hard jaws in the back. This is important. The concentricity of the
'washer' will help keep the bore round while you are boring out the
irregularities of a worn scroll. You can also turn the outside jaw
so that it will hold any pipe or other large work you wish to hold
from the inside. Then come back and bore a short counter-bore into
the front jaw about 1/4" deep. This will allow for holding small
short tube stock. The only draw-back to these jaws is that when you
take them off the hard jaws, you loose your alignment. However, if
these are to be the replacement jaws, this is not important. Be sure
you tighten the jaws twice when installing them. First snug them
down while pulling against the 'lash'. Then clamp down on some round
stock, and tighten them again. This way they don't move again once
you have them bored. The double shoulder of the jaws are meant to be
reefed against. Soft jaws are a good system. You have capabilities
in 1 set-up that hard jaws must be reversed and re-trammed to
achieve. And if you have special production work for say 10 or more
pieces, you can bore the jaws so they act like a close fitting
collet. So if your doing a 2ond operation on some parts the must be
held on a 1.106 diameter, you bore the jaws to fit. This acts like a
collet and makes for very accurate work. If you have a mill or a
milling attachment, you can make your own jaws. Lead-alloy or other
soft steel works well. Use CRS if you must. Ron (18531) |
| More on
chucking it |
| Mark, If your range
of size is so limited, collets may be the way to go. By collet chuck
do you mean a 3-C shank with a 3-4 jaw chuck? I imagine those little
toys can be expensive. Collets in themselves are very accurate. I
could typically hold a plunge cut in stainless to +or- .0005 T.I.R.
repeatedly. This was on a little Wade hand screw machine. A collet
is only as accurate as the headstock bearings of the machine you are
using. This is why some guys prefer 3-4 jaw chucks that can be
trammed by the operator. Or you can get soft-nosed collets that are
bored in the machine to a particular size. If they are done
correctly, they can be very accurate. I would advise against using a
j-chuck to hold small parts. The jaws are not made for holding small
work for 2ond ops. They are made to hold tools like drills and
reamers. If there is a monetary consideration, you could try to make
split-bushing inserts to hold your work. However, these are only as
good as the machine and/or its operator. You carefully turn and bore
the bushing with a lip on the front. Then using a very thin saw,
split it down on 1 side. The bushing is marked with an alignment dot
that matches the spot on the collet, chuck, or whatever is holding
the bushing. You lose some accuracy because your dealing with 3
diameters. In essence, accumulated error. It's really a matter of
deciding what you want, and what you can put up with. BTW what will
these parts do? If we knew that, we can probably give you more
useful advice. Ron (18586) |
| Dialing for
zero |
| There are some ways
to quickly zero most stock in the chuck. Lots of guys begin by using
their tool as a pointer. They watch to see the farthest point
between the two, and half that distance. This is then repeated using
the dial. If your dial reads 0-10-0,place the 10 side toward you and
move the work 5. Now do another rotation. Set low reading to zero
and repeat the sequence. In no time you will do this in about 2
minutes. Just remember to ask where's the beef and then take 1/2 of
it off. Ron (18604) |
| Some quick
tips |
| Just a few notes
here: 1.Spindle oil is suppose to be light so it can get around. I
use something called Mobile spindle oil from MSC. It also serves me
well for way oil. The reason car engines use 30w is that when heated
it gets thinner. It is also pumped through the system. Lathes of the
type we run have a passive system and do not get much more then warm
2.It probably is a scraping ref. gage. Though I did not see the
tool, the description sounds about right. 3.Newbie threading hints.
No gage ,no problem. Just use your pitch gage. That's the little
tool with all them pieces of steel what got wrinkles on 1 side. A
mag. glass will show you how far you need to cut. As for set-up:
keep it level, compound always points to the direction of travel,
use the same number on the thread dial if your not sure which one to
use. Take spring cuts and lots of oil. Ask me off-list if you want
more help. I have made all the mistakes so I'm beginning to know
what's right. In about a century I may even be as good as some of
these hot-shots! Ron (18680) |
| Re-boring
gears & shop tip |
| I haven't checked
the gears out as yet. I could plug them with brass tubing that would
conform to the shape of the bore, then re-cut the hole. I am not in
a real hurry to start this, but it will need attending to. I found
myself in need of a 1/2 reamer yesterday. The motors I'm re-building
get a new bushing in the cover-plate. Then they need to get a few
thou reamed out for the motor shaft. All I had was a nearly new
on-sized 4 lip EM. I didn't have the time to set this up in the
lathe or mill, so I did the following. 1.Take a dowel pin or drill
blank, and chuck it in the lathe. It snugly fits the bush. 2.Slide
the plate on to the pin until it is flush with the far side. 3.Bring
the EM you chucked into the tailstock up to the end of the bush.
4.Without moving the headstock, slowly turn the plate towards the
cutter. The pin acts as a pilot for the EM that is now a reamer. I
carefully went in about 1/2 way, and backed it out. I left a bit at
the end so that the nose of the bushing that gets all the work was
tight. To keep from having to do this again in the near future, I
made some boots that protect the shaft and bushing against
contamination. It seems to work well enough, so I'll put the grinder
back into service. Ron (18857) |
| Root canal for
gears |
| My take on teeth
would liken it to putting a crown on a ground down stump of tooth.
Much like a dentist would go about it. It may be a good idea to
first file down the site so it will be easier to drill on location.
Drill for 2 small pins first. Since you will probably not want to
disassemble the gear in question. You can drill for the pins by
first making a drill jig from a piece of hardwood. I'd use cherry.
After sawing the gear circle, (leaving a bit of wood to file) take a
file and shape the piece so it seats on to the top of the gear.
Remember your now a dentist! NO NOVOCAINE! Now carefully layout for
2 pines, say .040 in dia.? Drill both holes through the piece in a
drill press if you have it. After all this is done, take a drop of
super glue and stick the drill bushing you just made on to the drill
site. Clamp the gear in place as well putting it in grandmaw.
Carefully drill both holes, use no oil. Knock off the wood bush and
clean the site with alcohol. Mix some 5 minute epoxy, warm up the
gear with a hair dryer. Use a toothpick to put some glue in each
hole, now to each pin. Insert pins and give it a rest. Sometime
later our intrepid hero is about to make his tooth. Lay 2 pieces of
clear scotch tape on the adjacent teeth. Mix up some DEVCON ATOMIZED
STEEL EPOXY. Stir it up until it feels like it's going off. Using a
small craft stick, (you buy these at the craft dept. in Wally World)
put the devcon on the site where you will roughly model the tooth.
It is very important to have no voids between the pins. Let the
whole thing dry for a day. Strip off any masking you did prior to
building the tooth. Use a triangular file to finish the job. Now I
realize this sounds a bit like Ron Overkill, but it works. By making
a moderate production out of it, you force yourself to slow down and
take your time. Being meticulous is a real plus in this kind of
work. I learned this from a pattern-maker that could put us all to
shame. If the pins have a good close fit so there is just enough
glue to hold them, this job will last a good long time.It doesn't
take a whole lot of effort, just enough. Ron (19209) |
| More on boring |
| I never heard of
anyone actually breaking a compound before. It was either through
mis-use or a flaw in the casting, or both. SBL's and most every
lathe I ever ran is designed to bore from the compound. Otherwise,
how are you gonna hold the tool without doing some serious
re-working? To eliminate over-stressing the machine, always have the
gibs for both cross-slides snug enough so they have a very light
drag. Center the boring bar holder over the compound pivot point.
Use a boring bar about 1/2-1/3 the size of your hole. If you bore
for a 1/2" hole, just use a 1/4" bar. Another reason chatter happens
is pushing the cut,(hogging). I take .020 per pass. Ron(19557) |
| Cutting it |
| A lot of good
advice, as usual. The new technology can allow faster production.
Higher speeds, bigger cuts. I think along the lines of using HSS for
99% of all my work. A mirror edge can be obtained using lapidary
techniques, and some diamond paste. Try this. If you don't have an
arbor in your shop with 2 wheels on it, make one from yard sales.
Wheel speed to be about 1700 rpm. Put a 400 grit wheel on the left,
and a maple or beech wheel on the right. Both of them should be 8"X1
1/2".The wood wheel should run very smooth. If you want to make the
finish wheel to polish radii Cut these on the blank when you make
the wheel. Once this is done, impregnate it with 50,000 diamond
paste supplied by Crystalite Corp.
www.crystalite.com This
paste goes a very long way. You smooth out the wheel with 600 g wet
or dry, stop the wheel and apply the paste with your finger. Rubbing
it into the grain so it stays there. You may try wetting the wood
first to open up the grain, thus trapping the paste. As you polish,
any excess paste should be saved and used again. Adjust the stages
so both wheels cut at the same angles. I build mine with a compound
5 degree and use this for all my work. Touch the bit to the wheel
lightly, but firmly. If you did a good job with the 400 wheel, all
you need do is 'joint' it for a micro edge. Use this rig once and
you'll never want anything else. I designed this tool to give both
carbide or HSS bits a keener edge. Diamond wheels are very
expensive. Shop tooling like this can run into hundreds of dollars.
This is a knock-off from a lapidary's 'spool arbor'. We use these
rigs to get the ultimate polish on unmounted stones such as cabs and
faceted stones. My own opinion is that a super sharp bit will cut
better, and give higher finishes, while taking the load off older
machines. You can also do the same trick with drills and end-mill
tips. Just make a block with built-in angles and some bushings, or a
small chuck. Mount this on your tool post. Put the wood wheel in the
chuck. Put an index finger in the tail stock. The wheel runs dead
true. Bring the bit up to the finger, (a small piece of 1/4" round
stock bent at a 90 degree angle, and then filed to your desired
end). Set tool bit, lock slowly feed in to the wheel. Of course you
already know to run the wheel clock-wise at slow speed. Touch it
briefly noting the dial reading. Hmmm, now there is another idea
worth trying. If you were to build a 2-stage wheel set-up on 1
arbor. The 400 grit wheel larger then the finisher, and set to the
left. Dial in each edge at 400 and repeat on the finisher with the
same technique. That way you get a finished result in 1 set-up. For
better results, I'd use a dial indicator for all my readings. Hey,
with a little work you'll get better results then a white wheel on a
surface grinder at a fraction of the cost. Sorry this post is so
long, but I do my thinking while I type. Give this jig a run an come
up with some comments. Ron (19636) |
| Leather can be a
good surface to polish with. Mostly for curvalinear surfaces, like
cabs. I suggested hardwood for 3 reasons. 1.You can shape wood to
any profile to suit a job. 2.It is much safer. Leather may snag if
you should dig into the wheel. 3.With wood, there is no possibility
of nosing over your edge. Plus the diamond paste cuts quicker then a
cabin boy on a Greek freighter. Now about all those sore feet. I
have in my shop, a little wonder of a floor surface that is
re-cycled tires. Under the name of Enviro-care, this is a snap
together mat you can put down in a 20X20 room in 2 hours. It is a
pleasure to walk on, warm in the winter because it sits about 3/8"
off the floor. Has a tread built in so it gives as you walk. It's
great for unsticking cars from icy spots in winter, (I keep a 6'
strip in my van to pull out stranded tourists!). It sold for $2 a
square foot. It lasts forever, and is great for keeping the nasties
out of the bedroom. I found that metal chips on a waterbed can make
for interesting conversation at 2 AM...WE'RE DROWNING OR THE CAT
SPRUNG A LEAK! Not as tasty as sliced bread, but a good deal better
,(and cheaper!) then a pair of top of the line Converse shoes
that'll wear out in 2 years. I have this stuff in both my shops.
When you drop things as often as I do, (Right arm met with table saw
many moons ago) your tools don't go crunch. Why buy expensive shoes
when this stuff keeps tires out of the landfill? OK so it sounds
like a sales pitch. Here is the 1 draw-back. Since it is a
cross-ribbed product, small things like 1/8 drills and machine
screws smaller then 12-24 may fall through the cracks. For this you
just assemble the flooring so that the areas of high traffic can be
lifted up. It is a snap together floor. I use a dead blow hammer and
a block of wood. I cannot say enough about this product. Try some
local flooring places. There are several product names out there.
Ron (19642) |
| Ron, I use the
Norton diamond paste but I run much slower, about 400 to 600 rpm on
a 6" diameter. Also Tripoli on a cloth wheel at times. It depends on
what I am attempting to accomplish. The Tripoli and jewelers' rouge
is a lot cheaper. JP (19664) |
| Spanners |
| Frank, If you take
a short piece of stock and turn it down to the retaining ring size,
then use the nut as a drill guide in your drill press. A tiny spot
of super glue should hold it long enough for spotting. A B-block
will hold the jig in place. Once you got that, drill for a 10-32
flat-head screw and C'snk. Attach this to some kind of handle. Glue
the studs into their holes. The tool end will not have to be more
then !/2" long for purposes of turning and holding during the
process. The alternate way is to do the above using case-hardened
screws threaded into the wrench head and turned down to match the
pin holes. A lot of work! Stick to plan "A"! Ron (19706) |
| Staying on
point |
| Some stuff in life
is relative. No matter how big or small your work is, the tool has
to be on a cutting plane of best advantage. In my school days, we
use to get a block of steel and drill a 1/4" hole in it. Then bend
and grind a piece of rod so that the tip was at level point when the
base was sitting on the bed. With this tool most cutters could be
fairly well centered. SBL's have a mark on the side of the tailstock
ram for height adjustment. But if your turning a .031 pin, the
center point cab be very critical indeed! If your work should fall
into this category, might I suggest you make a gizmo that is quick
and fool-proof. It will get your location the first time, without
the need for a magnifier. Make a base that is small, but sits on the
ways. The base will hold the pointer at the correct location. Now
attach a 9-volt battery and LED circuit to the base. I'm not a EE
but a simple series circuit can be made so that when the tip of the
tool touches the pointer, the LED will light up. I got the idea from
one of those edge-finders sold in tool catalogs. Depending on how
elaborate you want to make this rig, it should work for most any
application. Ron (19827) |
| Making a tap |
| If you need to put
brass back on the end of a steady finger, just braze it. I did not
look close enough at the header to this thread. When I saw "bras
bronze stock" I thought it was an OT opera about Norse butch # or
other form of math...ahem! Anyway it is possible to make your own
tap for non-ferrous threading. I had to make a 1"-23 tpi LH for the
US Navy once. Just use good tool steel like an air hard. If it is a
thru hole, put a longer then normal lead on that sucker. I used a
radius cutter and off-set it for increased cutting efficiency. We
had no equipment to give it a proper finish grind, so I used a 3/4"
medium India stone to polish the flutes. I also made a setting ring,
and used it with #400 honing grit to lap the threads. It worked
beautifully cutting threads in a 1/2" 2024 alum plate. I have been
out of it for a while due to epoxy poisoning. Years of using this
stuff in the rock shop has gotten me a ALD. I advise anyone hear
that uses any forms of epoxy to take this seriously. If you do a lot
of glue work, wear a LOT of protection. Mask, gloves, suit etc. This
will keep you away from the ER. Out-gassing from mixing and curing
seeps into the pores, right through epoxy handlers gloves. I can
only wonder what it did to my lungs, (though I did wear a good 1/2
face bio mask). I may have already explained this but I cannot
remember. Take care around this stuff. Ron (19881) |
| Anchoring a
lathe |
| I've always
wondered why some people bother with this. Being in a frost prone
place like northern New Hampshire, unless you have frost-walls, the
floor will travel. In many discussions here, twist is more problem
then anything else. A lathe is designed to be an entity unto itself,
gravity being taken into account. Large equipment, especially
shapers and high vibration equipment, do need rigid placement. That
being said, here is my take on bolting down. Lathes under 10" swing
can be held using 3/4-10 all-thread. Drill and sink the rod with
hydraulic cement. Sit the legs on threaded plates. Hold the lathe
with thick washers and nuts after taking out the twist in your bed.
If your floor travels in a seasonal fashion, check the bed for twist
as per location. I recall an old machinist telling me about one mill
riting job he was in on. A steel plant in Ohio I think...anyway they
were sitting a new rolling mill. The machine was big enough as to
have it's own basement. To hold it in place they heated the 6" base
bolts, (about 8' long) cherry red. Then just spun on the nuts hand
tight. The cooling rods shrank ,thus putting all the torque
necessary on the nuts. Yet another success story of using mother
nature and physics 101. Ron (20548) |
| Chucking it |
| Pretty good advice
in my book. So just to re-cap,(and ad my .02: 1.Re-grind as per
Grumpy,cute trick there! 2.Go buy a new chuck.It will be better
then: a. a Chinese junk with a leaky bilge,b.what you have that is
far from what you really want. 3.If you have caps on your jaws,go
buy soft jaws and bolt these to the existing jaws.Or just get new
jaws that bolt on. Buck chucks have this feature.The scroll jaws are
tapped to accept hard or soft jaws.I imagine Bison does as well.If
you decide to buy new,be sure you spend the bucks to get a unit that
can be trammed in.Thus allowing you to work dead nuts by virtue of
aligning the jaws to make up for wear in the spindle. Ron (20603) |
| Truing chucks
& radii benders |
| Almost sounds like
a party for Charley! One thought, OK 2 thoughts on truing chucks.
thought 1. I wrote about the honing method some 3 months ago. I got
my version straight out of "American Machinist". What I did not
explain was that upon completion of the job, you must scrupulously
clean the lathe. In fact it may entail disassembling the chuck. The
slinging effect of the grit in oil will go anywhere it wants to.
Covering the bed and anything else is very important. But the chuck
can get a real dose of true grit during the process. thought 2. If
you decide to upgrade a chuck that has run-out, you will need a way
of holding the chuck in place once the backing plate is turned
under-sized. The adjustable chucks have screws you back off from the
front and sides. The side screws also act as keepers. I have learned
to use a certain amount of torque on both sets of screws once the
"00" is achieved. Otherwise, no matter how hard you tighten the
front screws, a knock or sudden or repetitive bump, (like turning a
square piece of stock) will knock it out of square. Now I cannot
verify this last idea seeing as I have never done this to a chuck.
But from similar experiences I know that a solid object set in
motion will seek it's own lash. To avoid this you could either
install 1/4-20" long set screws, or break out the shim stock and
tram with the shims so the chuck is still in contact on all sides of
the plate. RADII BENDERS: I think the list member may be thinking
about a roller radius bender. In which case they want to put wide
grooves in the side of the stock. If your going to do this, you
needn't make any fancy set-up. The 2 tools of importance are a sharp
3/8" radius tool, and a few homemade gages. Make the latter out of
thin sheet metal. Start by supporting the workpiece with a tailstock
center. Lay out the center-line and begin ditching. You will find
that slow speed and alternating cuts will keep vibration down to a
minimum. Use oil of course. Work left, right, then center. Once you
get to the bottom, begin roughing out the finished radius using your
gage. With a little filing, you can get a nice bending tool. This is
an excellent way to learn metal carving on a lathe. It's also a good
lesson in hand/eye coordination. Ron (21050) |
| One of the
first 'mods' I did to my 13" was to machine the back plate
undersized. I also had to drill the bolt holes oversize in order to
get the necessary amount of play to 'true' the workpiece. (I say
"true the workpiece" because nothing could possibly be done to true
the chuck - it being rather ancient etc.) So far it has never moved
out of the set 'register' on it's own, even when the dumb operator
(me - blush) ran the chuck into the crosslide. It is 'dream easy' to
zero a workpiece by slacking the mounting bolts and bumping the
chuck true. I suppose the potential is there for the chuck to move
on the back plate but experience has taught me not to worry about
it. Ken (21079) |
| Bore reaming |
| I like Toms method
of clean-up. He points out the importance of alignment. I'll add a
few other ideas if I may: 1.Be sure the reamer itself is in good
condition. Nicks in the tool aren't fatal, but a reamer that is
nicked and dull can actually make matters worse. If you just get a
new one and keep it as part of your tooling, (I'd keep it in a tube)
It's very presence pays for itself. 2.When you ream, pre-set the
drag on the quill lever. Oil the outside of the barrel and put the
squeeze on so you can still move it without a lot of slop. 3.Clean
out the grinding center hole at the chucking end. I use a pipe
cleaner and solvent. If you don't have a headstock center, throw a
piece of 1"stock in the 3-jaw chuck and turn down a center. It'll be
dead true because all the inaccuracies are turned out. 4.Use a
little oil when reaming. A slow turn of the wrench and inspect the
progress. 5.Nothing has been said about the cause of bore being
galled. The tools you put in there should be stoned for hi spots. I
use a medium India stone and use a circular motion and diesel. Only
hit the high spots. Rust is also a problem. Keep your tools oiled.
Ron (21291) |
| Ron, Your info is
always appreciated as with others who have been on the shop floor
for more than a few years. I will add, try not to (or don't) turn
the reamer backwards (reverse). This can damage the flutes. They
also sell some plastic morse taper cleaners. Might be worth the
money. Grizzly sells them. Tom (21294) |
| Tom, that slipped
my brain pan. The point we are making here is to only take out the
high spots, NOT the whole bore! You can see the progress you make if
you paint some layout dye or magic marker on the bore hole. This
lets you see exactly what you take off. As for a bent shaft, get 'er
done by checking that shaft with an indicator. Ron (21313) |
| Old tricks
for old lathes |
| I should have
commented on this earlier. A worn lathe is not an abused lathe as
such. Most of my professional life was built around used equipment.
I can still remember watching the boss take a side grinder to an
1898 Hendy lathe because the ways near the tailstock were high. The
rest of the bed was THAT worn! Ummm, do not try this at home, the
lathe genie will pay you a visit in your dreams G When I was at the
MT.Washington Cog Railway, we used the original lathes and mills to
re-build the engines and rolling stock. The Prentice lathes there
were probably 16"X120"CC.I needed a overhead crane to put the axles
on center for turning. I used water power to turn the lathe and DC
lighting to see by. The EDISON ELECTRIC COMPANY ampere meter would
peg each morning when I started the turbine. These were old lathes
that were in satisfactory, but not excellent condition. Grit and
coal dust gets on everything. Our only heat was a large pot bellied
stove held together with prayer. Among the many tasks I had to
perform was making sleeves for steam valves. They had to be very
accurate. The 6"X14"sleeve had a moving valve in it. This assembly
was then pressed into a housing. Fairly tricky as there were no
drawings, and everything was NOT interchangeable. You could not for
example take a piston head off number 3 engine and put it on number
9.The bolt circle wouldn't fit. (They were double-acting cylinders)
These were primitive conditions. Exactly as they were in 1910.It was
an antique machine shop. No DRO's or digital calipers. You used
mic's that went from 2" to 20".But we did it. Knowing the quirks of
a machine was like having a road map. A good machinist can operate
under these conditions. Each morning 8 engines were under steam and
went up that insane hill of trestle and wind. Many times the
passengers were told to open the windows so the wind could not push
over the train. I once spoke to a touring retired engineer. We
talked about the old days. He remarked how people once built their
own homes and then made the contents that went in them. It was
expected that you did a good job of it because back then you learned
how to do this. This same truth holds with metal-working. It is the
man not the machine that makes a shop quietly hum along. It is
expected that you knew what you were doing because the health and
safety of others depended upon it. So when you see an old lathe with
saddle in it, just remember that the operator will fill in the holes
and twist with experience and good judgment. Two qualities that
along with integrity, are being dispensed with these days
unfortunately. Ron (21398) |
| Hooray for Ron,
I've been a machinist for 18 years and teaching machine shop for
almost as long. Ron's observations are right on. I have seen so many
people spend so much time focusing on their equipment when what they
really want to do is make parts. Good work can be done on worn
machinery if the operator is paying attention to what's happening. I
spent 10 years in a shop working on old equipment and turning out
quality work. Imagine a milling machine with worn ways that wouldn't
cut flatter than .007" over one foot of travel. Simple, just pre
stress the center of your part to make it belly up, check the top
surface with a dial indicator and adjust the part to compensate for
the crown of the ways. When it's unclamped then it's flat. I ran
another horizontal mill where I had to shim .012" under the front
corners of the part to cut the face of the block perpendicular to
the bottom. If you want to spend your time working on your machine,
that's fine too, but don't use a worn machine as an excuse to not
use it to make parts. It's like the old saying: We the unknowing,
led by the unwilling, have been doing so much with so little for so
long that we can now do anything with nothing! The guy who says it
can't be done shouldn't interrupt the guy doing it. Gordon (21455) |
| Shop notes |
| My .02 for how much
to take off per pass. In a production setting if you were running a
manual lathe (not CNC) it was generally 3 passes to finish your
basic cut. When you read about what a SBL 13X36CC could do, keep in
mind that this cutting rate is for equipment in fair to top running
condition. The older a lathe gets the more you should pay attention
to things like wear and tear. Most of us have equipment that
witnessed WWII. Worn bearings and ways tell it all. So Ron's cutting
rates for tired machines is as follows: If your a hobbyist, what's
the rush? My 10X28CC SBL, takes a nice .020 per path, direct
reading. I use the smaller of two motor shivs. I do not use
back-gear, just low range, (this is slow but not radically so. I put
the tumblers into 'C', left tumbler and 1/2 way in the middle on the
right tumbler. This isn't exact because there are other factors
involved in cutting feed-rates. But for CRS it's close enough. My
rule of thumb (who came up with that phrase anyway?) was hammered
into me early on. The more you cut the slower the feed-rates and a
slower RPM. To prevent hogging never set your tool pointing to the
left. Unless you like bent shafts and broken tool bits. Set them at
90 degrees so that when you hog, it will only push the tool away
from the shoulder of cut. I set my tool dead-on center with my 6"
scale. These little 'pocket scales' are .020 or less. By placing the
scale between the tool and the work, you can tell if it's high
(tipped away from you or low tipped toward you). Keep your tool
short, and the tool-holder as close to the center of the compound as
is practical. Honing a tool with a fine stone, and then polishing it
with a hard Arkansas stone is all you really need for sharpening. My
personal preference is to use a tool grinder with face and side
capabilities or better yet a surface grinder. Find one of these that
has a worn out price. It's worth the re-build. As for tool geometry:
top view, front edge backed off 10 degrees from left side. left side
backed off 3 degrees from point back. All clearance rakes 3 degrees.
Stone a small radius on cutting tip. It's that simple. For more on
this e-mail me off-list. There's enough material in this piece to
warrant a look in a book or net archives. Ron (21765) |
| Finishing
alum |
| In my experience,
you need to have a nice sharp radius on your tool. A 1/8" radii may
be all you need. Here's how. Take a piece of HSS. Set the bench
grinder for 5 degrees. Grind the front and side of the tool with
this setting. Use a continuous motion around the tip. This is most
important. Now set the grinding stage to 7 degrees. Grind the top of
your tool by making sure the left side points up. Kant it back a bit
so the actual cutting tip is the highest point of the tool. Now for
honing. Place the tool on your flat bench. Take a fine India stone
so it sits on the bench but leans against the tool. By holding the
tool bit with moderate pressure, (to keep it from moving) gently
work the stone around the radii. Use diesel as a honing oil. Use
long strokes. A triangular stone is best. Now carefully place the
stone on top of the cutting area. Use your index finger to hold the
stone on the top rake and gently move it back and forth a few times.
Enough to put a micro joint on the edge. If you really want a fine
edge then go to a small hard Arkansas stone and repeat the process.
If you did this with all your tool bits AND kept them in their own
slots or cases, they will need very little care. That is until you
do some rough work. Ron (21889) |
| More about
tooling |
| I did want to point
out 1 other thing about broad nose tools...they can chatter. Many
machinists (like myself) use sharp profile tools to (with a stoned
radius of .030)eliminate the possibility of tool marks due to
chatter. Too much tool engagement on a thin shaft or unsupported
work-piece. Now you can find finishing tools in the old books that
look much like a plunge tool. They have a square nose with radiused
corners. If your lathe has enough beef and can take the strain,
these tools will work. To illustrate this let's use a cut-off tool
as an example. It usually has a straight profile that often has an
angle that skews to one side. The operator wants to either have a
flat face for the next operation, or wants the parted off piece to
have a flat face. If you have a small lathe, say 9" or under,
parting off is a real pain. The tool will either dive and grab,
followed by a snap and much talk about the pedigree of said
operation it's sexual activity, and it's final destination. The
reason for this is simple. The tool was to damn big for the job at
hand. Too much engagement of material for the size and beef of the
lathe. You can decrease this problem by using back-gear and a
constant drip of oil to keep from grabbing the tool. You can also
run the tool upside-down, and run the headstock in reverse. The tool
should not be less then 1/16" wide. And take care that the chuck
does not un-screw. I once saw an inattentive machine operator
experience this phenomena when the 12" chuck of his lathe came
loose, and did a walk-about around the shop! But back to my original
subject. If you want a tool that will give some kind of useful
finish try this. Grind the tool bit so it has a radius of say
1/8".As you form the tool on the tilted grinding stage, give it a
Hudson Terrplane sweep. A slight angle away from the work so it
still gives some finish while not chattering to much. Finish and
hone like I explained in my last post. Let me know how you do. Ron
(21894) |
| Threading
blind |
| Threading without a
dial can be done if you have reverse on your lathe. The trick is to
NOT disengage the half-nuts. At the end of your cut, you back out
the cross feed dial while stopping the machine. After the cutter
clears the work reverse the headstock by turning the switch to
reverse. The machine will return to your starting point. By leaving
the whole machine 'engaged' you only need to keep turning the
compound knob in a bit at a time. The cross feed always stays at
zero of course. The work is always turned to final diameter plus a
few thousandths for filing. Spring cut every 3 passes. That means
you leave the compound set and return for a clean up pass. I take no
more then .005 per compound dial. BTW to see how much you are taking
on the compound dial place a dial indicator on the tool post and
move the dial while the tip of the dial is touching the work. Note
how in a 30 degree angle it reads less then at a 45 degree. Write
down your readings. It's a good thing to know. A journal next to
your lathe acts as a second brain. Ron (22035) |
| Gene's bolt
|
| Taking out bolts
are far simpler then taking out taps. My favorite tool is a
left-handed drill, followed by a left-handed tap and matching screw.
One of these will do the job. They can also provide some levity in a
shop setting. Like when another worker begs the use of a tap. And
they NEVER bother to look at the thread direction. The tapered tool
without wrinkles is called an "Easy-out". With the correct size
drill and hammer, it will work. You need a tap wrench or be real
steady with an open-end wrench to use it. Ron (22157) |
| Thread &
files |
| I've used some
pretty beat equipment to produce a usable part. Even a severely worn
lathe can produce good results. Some suggestions: 1.A sharp tool is
nice if you want to keep sharpening it. Stone the nose a bit unless
you want the first pass to do it for you. Sharp tools mean they will
produce a good cut but not necessarily a mirror finish. Good stock
like tool steel will give nice finishes with a tool ground on a 60
grit stone. A few licks with a medium fine India stone is fine for
most work. 2.Place the tool on center. Use your scale between tip
and workpiece. If it is straight up (viagra position without tilt)
it should be on location. 3.Some lathes need a personal touch. After
each return grab the tool post and pull it to you along the compound
axis. This takes the 'lash' out of everything. 4.If you want an
impressive finish, use spring cuts every third pass. This shaves
some built-up spring pressure off the part. Finish on zero plus
.003.This takes it off both sides at once. 5.And for that simonize
look, use a 3 corner file and some 220 grit wrapped around it and
give the threads a quick polish. Another way to give the thread a
ground look, is to find a nut the right size and split one side of
it. Pry it open just enough so it will be a few thousandths big. Mix
up some fine grit and oil,(400 G oughta do) smear some on the shaft
and run the nut up and down the workpiece while tightening down on
the nut with a clamp. OK so it's a cheap shot, but it works. Good
luck! regards, Ron OOPS almost forgot! Frank, just grind that sucker
the way you want it and re-harden it. A blow torch or other large
flame will do. I use my wood stove. Grind the file to shape without
regard of temper. Then cherry up the last 4".Quench in cold motor
oil and carefully finish it up nice and bright. Take a propane torch
and hold the flame to the file 1/2 way down the length of it. If you
did a good job on making the tool bright 4" behind the tip, you will
see your progress. As it heats up the color will run toward the tip.
You want the last 1" a light straw color. This will take the worst
of the brittle out of the tool. Hone it up and cut away. If this is
too much trouble, just take a HSS tool bit and weld it to a piece of
1/2X1X12" hot rolled steel. The HSS will not lose it's hardness, OR
do the same with a piece of carbide. Just sweat this onto your file.
All of the above I have done and they work. (22179) |
| Support and
radio |
| Mike, If I
understand your question it appears you have a taper that will be 2
1/2" long. My rule of thumb is that. Any piece longer then my thumb
gets a tailstock support. If it's a thin piece or a small lathe more
support may be necessary. If your compound knob looks like it may
put your fingers at risk, switch the handle end to the opposite
side. Also keep in mind you may have less screw then the length of
your work-piece. In that case you'll have to do it in 2 bites. In
that case get your felt pen and ink the machined surface you began
with. If you are careful you will be able to match both passes. Use
a hand lens to see how close you can get to taking off the ink and
not taking the stock. Back in the old days the Scully Lathe was king
in the recording industry. The platter usually was a piece of ground
alum or cast iron that weighed in at 200 lbs. I say this because I
use to be in commercial radio. Our station was located on the
barrier island of Palm Beach. The record lathe is still the only
device that can be used without assistance of computers. It's
reader, the record player will always be around and used without any
assistance of electricity. Like the lathe and milling machine, it
only needs movement to work. Edison did get that one right. Ron
(22189) |
| Brass nuts |
| This is one of the
easier replacement jobs that will give you lots of experience. I'd
re-make that part. I'd make a set of (2) brass nuts. First
experiment in alum, after making a good drawing of the original. You
can make the new set with some adjustment screws. A brass tipped
set-screw placed at the right spot can act as a take-up for lash. Or
you could use a spring-ball set-screw. These exist at MSC. The
spring-ball acts as a tiny ball screw that will help with slop. You
may be able to place the ball screw at the oil hole if you have
such. My 10" does. Just take it out when you want to squirt some oil
on the threads, then replace it. But like I said experiment. Once
you have the design you want keep the drawing on file so others can
learn from your evolving talent. Ron (22198) |
| Old lathes
new tooling |
| At the time these
lathes were new carbide was still a new idea. Today's tooling is
designed for faster speeds and much harder wear and run. Although
they were tighter when new machines of the WW II vintage may not be
up to this kind of abuse. Yes I did say abuse. Our recent times of
slam-dunk machining take a toll on both man and machine. I use slow
speeds and HSS for my 10" SBL. It has poured babbitt bearings. As
for lantern post boring bars, get a cube of steel and with your
4-jaw chuck drill the post bolt hole. Put it on the compound and use
a square to line it up. Then put a drill in the chuck and drill the
bar size right thru the block. You now drill for set screws and your
bar holder is custom fitted to your lathe. Ron (22356) |
| Face plate
work |
| For my 10",I used
the 6" driver dog plate, and an 1 1/2"X10" bar stock slice. I think
I paid $5 for the latter at a junk yard. I laid out the backing
bolts with a surface gage and drilled the locations. Since the plate
was thicker then the driver, I tapped it instead. I then zeroed it
and took a kiss along the dia. and the face. Then flipped it and did
the back. I checked the driver plate first though. I did the same
with my second plate, this one being a piece of alum jig plate. This
time though, I did no tapping, preferring to use case hard bolts and
nuts to hold everything together. I used (4) 3/8-16 flathead socket
C's ink's. It's always a good idea to tram and pin any plate. The
pin should not be less then 1/8X3/4" dowel. It should be removable
with a knock-out bar. There will be times when you will want a
sacrificial pin for some work. A lead alloy or alum pin is fine.
Skinning the face and OD gives a dead flat and square surface to
work from. One of the least thought of jobs any lathe can do is
precision hole boring. Using jig buttons, a series of holes can be
drilled and bored to great precision in the lathe. I learned this
from an old fart back in '59.I'd visit my dads needle shop and see
Mr. Jager making die sets on my old 9" SBL. He would use a surface
gage to mark a hole location, drill tap, then locate his jig button.
In no time, he had that die in the lathe and trammed in. Since he
could go point to point drilling and boring, the holes were very
accurately located. They don't bother even mentioning this practice
in trade school anymore. Since computers have taken every bodies job
including Gods, who needs this junk? Right? A lathe can do HBM and
V-mill work. It may take a little longer but when a lathe is all you
have, it'll get the job done. Mr. Jager only had that lathe, Atlas
drill press, and a worn out band saw to work with. Oh and a
home-made die-filer. The latter being a most accurate tool that will
use and file or stone to finish profile small parts. Ron (23537) |
| Tool grinding
101 |
| I've been watching
this thread without comment. As usual, all the necessary things have
been said. Now for some kinks. Grinding carbide is easier then you
think. Go to a woodworking store or gem and mineral show. For about
$15 you can buy a set of diamond burrs. Usually electro-plated to a
5/32 shank. You must use water when working with them. Or mineral
oil. A Dremmel or other high speed motor is best to use with
diamond. I prefer 5,000 rpm max. If you can go to a hard surface
flooring store, you can buy an MK Diamond blade. A 6" continuous
sintered diamond rim is best. Mount it on a grinder with a guard.
Put a drip can of water over it. Along with the burrs, you can cut
HSS or carbide all day long. The burrs will shape and polish any
tool bit. The blade will go through HSS without heating. You can
even make your own sharpening stones. I do this all the time. The
burrs can grind out broken taps, and shape any stone or metal. If
you really want to up the ante, get some 50,000 diamond paste. It
comes in a syringe for about $20.Mount a piece of rock maple on a
1/8" dowel pin. Shape it on the lathe. After you have a good shape
finish it with some 600 grit wet or dry paper. Mix a drop of mineral
oil with a BB size bit of diamond paste. Or better just use it out
of the tube. Anyway, smear a little, VERY little on the wood burr.
Touch your tool to this polishing burr. The edge will take on a
mirror finish. It works well with felt or leather as well. Imagine
what it'll do to your wood working tools. The edges around my shop
are scary sharp. I have the railroad tracks to prove it...don't ask!
You can use your lathe to sharpen tools as long as you are careful.
Ron (23785) |
| Hadn't thought of
maple. Cast iron also works good as a mandrel to hold diamond
particles. Commercial diamond cutters use cast iron laps. Probably
not a good idea to do over your cast iron lathe bed. JP (23787) |
| Centering
tool & knife-making |
| My experience with
centering gages is a KISS principle. Old Harvey once showed me this
trick. He used the usual pocket scale made from .020 steel. I use a
1/2" wide strip of phosphorous bronze .020and 6" long. What I did
not see in all the posts was where you put the scale. As in the old
lever or wiggle indicators, you use the length of the arm or scale
to see the maximum deviation. Just place the scale at the tool on
the 1" mark and gently touch the tool to the scale. It will
immediately show any off-center deviation. The old indicators were
made on this principle. A small scale on the end of the gage would
show how out of round the piece was in the chuck. It is not
surprising that these old gages were just as accurate (.001) as most
new ones. I was a former member of the SCA, a Medieval reenactment
group. We had period knife and sword makers in our guilds. Many of
the processes described so far were general practice. If you can
catch the 'Tool Box' segment on the History Channel, you will find a
sword and armor maker I consider a national treasure. He lives in
VT. I think. I made some knives that would impress anyone silly
enough to walk into them. A large dagger about 12" long was wrought
from a truck spring at the Cog Railroad. It had enough carbon in it
to forge, grind and re-harden. Files are my best source for tool
steel. I look for the shiny ones at garage sales. If your smelting
and casting, they make great additives to the charge. For useful
tool steel such as punch and die or edge tools, they are good enough
for my purposes. I once made a tapered double-edged dagger on my
lathe. I could do a perfect hollow grind on my 9" SBL. By mounting
an arbor with 6" wheel between centers, I took a roughed out file
blank and clamped it into my tool-holder. Actually it was a cobbed
together clamp that bolted to the shoe on the compound. It is
important to support the end of the blank. Rather then take up more
bandwidth, I'll reply to any serious inquiries. I have never
divulged this process I accidentally stumbled onto some years ago.
Ron (23912) |
| Some reaming |
| About reaming. When
I was at the cog we would drill bore and lap to pin fit. The work
was a little larger then you will be encountering, but the idea is
the same. Long ago they didn't have real good tooling, just real
good men that took their time with primitive tools. For small work,
get screw machine drills. Buy a good American HSS brand. Make a set
of 'reamers' by re-grinding the ends to cut like an end mill. Their
short length gives more beef in tight places. Make up a kit with a
rough drill, bore drill, and hone. This is a good way of saving time
for those most frequently used sizes. Most reaming is for the last
few thousandths. Never more then .005 IMHO. JP may shed some light
on this. Small stub boring bars can be made from good drill blank
HSS. A set is easy to make. For a typical hole I do the following:
Hole dia. is .125 finished. Rough drill@ .0115, bore with bar or em-type
drill .122.Finish hone with split honing bar and 180-grit with light
machine oil. The first 2 tools give a round, straight hole. The hone
is for finish and final size. Just remember to split the work up so
the last 2 tools don't have much work to do. Get some brass and a
few 4-40 set screws. Drill and tap each bar-end after you have
turned them to a size just under a hole size. Then go back and
either use a slitting saw or jewelers fret saw. Carefully saw down
about an inch or so. Thus allowing for adjustment as the hone wears.
Reamers are nice to have. They are fast and leave a clean hole. They
are a real pain to sharpen. I use hones. They are slower, but the
fit is exact. I also cheat by using 600 grit for a air-tight fit. Of
course we all know I'm nuts too! Now ask yourself something. How did
the watch-makers of the 1800's ream holes they could barely see?I'll
shut-up now, time for drugs anyway. Ron (24041) |
| Some more
shop helps |
| Dear Frank, Your
post got me thinking.There is a way to get a better finish using
what you have in the shop.First off.For those of you who are short
on gage blocks can always make one.Turn a 1" piece of any straight
metal and use a good sharp tool to face the ends.Leaving the last
.005, mount a stone carefully in the tool holder.Using light oil lap
both ends until it matches the sine you are looking for.I'll bet you
can get within .00001 or as close as your best measuring device.
Frank,here's an old trick only a simple mind would dream up.Go tool
up an adapter that easily fits onto the compound handle.Turn down
the opposite end so it fits a small drill motor.Use your imagination
duct tape,bailing wire,whatever to cob up a resting place for said
motor.Practice on some scrap stock to see what is the best setting
for the variable speed D/M you are using to power the compound.This
will work.Since we are talking finishing cuts,the short distance of
3" or so is not impossible for this set-up.The drill factory I
worked in had the same set-up using air instead of electrics.But the
theory and practice is the same.Mirror-sharp tool with 1/8"
radii.Snug up the gib for a light drag.As usual,the set-up takes
longer then the cut. More shop notes.In a thread that was started
prior to this,there was some discussion about cutting stainless
steel.Sharp tooling is necessary.I used a surface-grinder to do all
my Momax HSS.I was looking for a greasy edge.My mentor/foreman said
I wanted an edge that could give no purchase and therefore could
withstand long use with high finishes.I was doing small parts on a
Hardinge hand screw.I got bright finishes and .0001 TIR conc. I used
sulphered black cutting oil. A fine-cutting wheel that gives a
bright finish can be had from almost any supply house.But a
rubberized brightboy will do nicely.I flat-ground all my tools
because I could. But a hollow-ground tool will work. Wipe all edges
away from the rotation. This keeps the wheel from riding over the
edge. You can put a finishing wheel on your bench grinder. I took
some stock, and made an adapter that was threaded onto the right
side of my bench tool grinder. It holds the finish #220 wheel in
place like a nut. The outboard end is threaded to accept a 3/8"
Jacobs chuck. It extends far enough off the grinder to allow for all
kinds of finishing. I mounted a 3"X 1/2" BrightBoy #400 grit in the
chuck. I cobbed up a stage to rest the tools on. Works great. Comes
off for other work with a piece of 1/4 round stock. Ron (24630) |
| Getting by |
| So you have some
run-out problems. The sensible thing it to 'bottle-neck' the machine
for accrued error. Having a good register is important. But you can
have a food fit and still have problems. If the bearings are not
properly set, you get vibration and sloppy work. Taking too big a
cut will make any lathe run badly. But for now let's assume you have
a worn but otherwise acceptable lathe. You want to turn fragile or
thin tubing. Here are some ideas: 1.If a tube is thin it will
distort if you let it. Making a slip-fit plug goes a long way
towards getting a grip on things. 2.Use a pot chuck. Probably the
most accurate way of dealing with the difficult part. A piece of
stock that you turn to fit work that is to be finished. The end is
slit. Then used in conjunction with a hose clamp, it holds light
work. It is also a 1 shot deal, once your done with it. 3.Other
holders like the standard split-bushings, can make things easier to
work. But you asked about better ways to chuck faster. If I were
using a 4-jaw chuck frequently, I'd make a 'speed-set'. This is
nothing more then a piece of any metal that fits into the tailstock
chuck. You make this rig in 1/8" steps or smaller/larger to suit. It
resembles a step cone. Each step is large enough to touch all 4 jaws
to. Then you slip in the workpiece and tram in. Some guys just keep
some stock pieces around that fit into the T/S chuck. But if you
work with the 4-jaw every day, the speed-set is worth the trouble.
Another method is as simple as reading a scale. Put a point in the
T/S.A center-drill works well. Take a scale and find the radius of
work diameter. If your using 2" stock, make it 1".By touching the
end of the scale to your tool-bit, dial the scale so the pointer in
the T/S hits the mark. Now, leaving the tool in place, slip the work
into the jaws and begin tramming. Since your tool is at the location
of radius, you have a benchmark to work to. Install a rod that will
accept a dial ind. near to the chuck. A shelf over the lathe can
work if it is sturdy. You want to have the dial handy so you can
quickly finish tram the workpiece. Just make it so it can swing out
of the way when your done chucking up. A plastic baggy keeps it
fairly clean. The 3 and 4-jaw chucks are only as good as the total
acceptable wear of your lathe. An experienced machinist that knows
the quirks and limitations of his machine can do some wizard
tweaking. It takes time to set some work. Knowing when to stop is a
matter of patience and wisdom. Ron (25030) |
| Small holes
on hard steel |
| Here are some more
ideas when working on ticklish parts. In your case the caliper is
electronic, so anything like EDM is flat out. There is however
another way. Begin by going through the piece with a small diamond
burr. Use oil or water to flush the site. Then go back with a
carbide end mill or drill to size the hole. The other thing that is
slow but works is a piece of brass tubing you make to order. Mix up
a tablespoon of #220 silicon carbide and 10 wt oil. The brass tube
becomes a drill. With everything held in place, star up the drill,
add some slurry, and begin drilling. This will work and give you a
nice finish. You can even cut threads this way if you have to. Ron
(25661) |
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