| Acme treading question.
(Sep 27, 2001) |
ACME? (Jun 7, 2004) |
| Sources for Acme taps
(Nov 30, 2001) |
Acme taps part 2 (Jun 10,
2004) |
| 7/16-10 LH Acme tap (Sep
22, 2003) |
Acme screws (Sep 2, 2004) |
| ACME (Mar 21, 2004) |
Acme Taps for Brass insert on the
compound (Jan 25, 2005) |
| |
| Acme treading question. Hardinge |
| It seems
I'm faced with cutting several acme threads, L and R handed. In all
the printed material I've been through it is always compared to a
square thread with details on how to grind a tool to cut square
threads. They usually finish with "acme is used because it is easier
to cut..", and "acme uses a 29deg angle..". My question is do you
need a helical relief on the tool like you need in a square thread,
and if so is it the same formula as the square thread? Looking
forward to grinding some really funky tools.
Frank (1631) |
| 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. 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) |
| Sources for Acme taps |
| I'm looking for a
3/4-8 acme tap. Anyone in the group have a good low $ source? The
best I've seen is about $100. Ed
(2291) |
| This months MSC
metalworking flyer has them for $35.38 for the right hand Acme
3/4"-8. They are class 2G for use in brass, cast iron, free
machining bronze, zinc and aluminum die casting. Thread length to be
tapped shouldn't exceed 1 1/2 times the diameter. Don't know if that
is what you're tapping, but it sure beats the hell out of $100. Dick
(2292) |
| I checked
this out and the taps are plug not tandem. The plug will cut a full
depth thread but it will not have as good a finish as the tandem
type. I'm reconditioning a set of 9" S. B. half nuts and think I
really should consider the thread finish as a major criteria. Ed (2296) |
| I bought a tandem
3/4 X 8 acme 2G tap on ebay from dib2 I am sure I have seen more of
the same from this seller. If you want to collaborate on a halfnut
renewal system, I am willing to help. I live in the Chicago area.
Glen (2300) |
| 7/16-10 LH Acme
tap |
| Does anyone
know where to get an 7/16-10 LH acme tap so I can get the slop out
of my cross slide by making a new cross slide nut? What does a new
one (nut) cost at Southbend? Rick (14122) |
| I shopped for
a tap, found that nobody had one in stock, and the best price I
could get for making a single tap was $125. I went ahead and bought
one from Leblond because I'm impatient, and it cost $68 with
shipping. I also had to shim behind the dial to remove some of the
backlash. Acme inserts are available, but I doubt they are small
enough for the diameter. Maybe one of our deeper pocket members
would buy the tap and provide threading services to members for a
nominal fee? (14123) |
| Have you
tried Tracy Tools in Dartmouth, Great Britain. They sell lots of
taps of various type in many pitches and sizes both current and old
and absolute sizes, they also do acme taps both left and right hand.
They have a web site at http://www.tracytools.com and their phone
number is in England 01803-833134 their prices are very reasonable
and their service i have found to be good. John
(14124) |
| Rick, You might try
some of the SB used parts dealers. They sell parts at reasonable
prices. I have bough ten the cross slide nut from Plazza. It was $35
from memory. You might think about the cross slide screw also. It
wears too. I think Joe sells stock for this or you might try McCar-Masters.
You have to sleeve in the new one. I think Joe also offers to do
this for about $100. Also, worth a try is Sobels and Meridian. All
of them have excellent reputations. I have dealt with Meridian and
happy. I haven't dealt with Sobels, but hear good things about them.
Tom (14125) |
| I just made a
cutter from an old hex key and cut the threads on the lathe. Re
built two old Atlas and a Craftsman this way. (14136) |
| ACME |
| I have a craftsman
screw pitch gage made in England, they go from pitch 4-18,52 to 84
and 20 to 50. My set don't have the pitch to read some of the threads
on my SBL. What set do I need for ACME threading and where is the
best place to order them. Leeg2543 (17876) |
| Leeg, ACME threads
are 29 degree. I use a B S #715 gauge (1-10 TPI) or Starrett #284
www.MSCDirect.com has 2 choices: 06377014 or 86412632 RichD (17877) |
| ACME? |
| I have seen in some
postings that parts are acme. As being non American I wonder what is
acme? I made a search for acme on the internet and came up with:
(American Company that Makes Everything) Torfinn (19531) |
| Acme is a
screw thread form standard having 29ø flank angles and flat crests
and roots. Typical use is in machine tools and lifting gear. See
Machinery's Handbook for details. RichD (19532) |
| Acme taps part
2 |
| Found a place with
a lot of acme taps in stock. Plus they take Paypal and you can order
online. Not dirt cheap, but not outrageous either.
http://www.e-taps.com/ (19592) |
| Acme screws |
| Also check
McMaster-Carr They have a very extensive line including a precision
line, which is what I used on the crossfeed of my 13 inch. Replaced
both screw and nut now have less than 4 thou backlash.( have another
lathe , old Logan and a Bridgeport to do machine work on). Quite a
project but only about 70$. Mitch (20737) |
| Mitch: Found the
same thing in the MSC book. What I was wondering which type of nut
did you use for the cross feed? Vinnie(20747) |
| Vinnie, I will look in my files and let you know which nut I
used. I have seen where some guys machine a steel holder and insert
a acme nut, but I think the McMaster-Carr had a extra heavy
precision nut large enough that I actually machined the boss and
flats into the nut itself. It is quite a project and requires a
Bridgeport and another lathe with a four jaw for the nut and I used
5c collets and a live center to machine the screw. The Bridgeport
was used to machine flats on the side of the round nut, plus while
you have it in the vise you will need to pick up the center in both
axis and center drill the nut, this will be used in the four jaw to
indicate from and will also be your boss and threaded mounting hole.
I will get some numbers for you later on McMaster-Carr catalog
and get back. Mitch (20779) |
| Acme Taps for
Brass insert on the compound |
| Someone was going
to post where to get modest price Acme Taps 7/16x10 LH for the cross
feed and 3/8x10 RH for the compound Monday. Did I miss this
information? Dave (24256) |
| 7/16-10 LH $73.003/8-10 $51.00 At those prices, you might be better off
buying new nuts from Miller Machine and Fabrication. Prices listed
are: Cross feed nut $50.00 Compound nut $28.50
http://www.millermachineandfabrication.com/ No connection. Webb (24271) |
| Webb: I think you
may be right. As long as some one keeps making them. When I wrote
the post today about this I type MODEST PRICE TAPS. Someone had
posted last week about $20.00 to $30.00 taps. At that price I would
spring for it. Dave (24288) |
