|
|
| 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 | |
