Subject: Re: Need help finding Acme tap

From: [email-masked]
Date: 12 Dec 1996 20:07:30 GMT

In article <[email-masked]>, [email-masked] (Rebecca or
Jim Schwitters) writes:

>I need to renew the cross slide and compound lead screws and nuts in
>my lathe.  I can easily turn the screws but the nuts are another
>matter.  Although available from the factory (Schaublin) as
>replacement parts,  they're considerably more expensive than I can
>easily justify.
>
>Any help will be greatly appreciated.
>
>

Can you bore the thread out of the nuts and turn down some stock acme nuts
for a press and pinned fit?

I was not aware there was such an animal as a metric acme or buttress
thread. I have only ever seen inch versions in metric machines.

Peter

---

From: [email-masked] (Jonathan M. Elson)
Date: 12 Dec 1996 05:49:58 GMT

Rebecca or Jim Schwitters ([email-masked]) wrote:
: I need help finding a source for a non-standard acme tap.  I want a
: 9mm x 10 tpi right hand acme tap but could substitute a 3/8" x 10 tpi
: if the metric is too hard to find.  None of my catalogs or other
: sources list such a thing.

: I need to renew the cross slide and compound lead screws and nuts in
: my lathe.  I can easily turn the screws but the nuts are another
: matter.  Although available from the factory (Schaublin) as
: replacement parts,  they're considerably more expensive than I can
: easily justify.

MSC has these, although they almost certainly don't have the bastard
combination 9mm-10TPI Acme.  They have 3/8-12, 1/2-10 and others.  They
were on sale in November.  the 3/8-12 was $49.33 (reg price $70.54,
right hand only) the 1/2-10 was $44.85 (reg $64.07, both rt hand and
left hand thread available).  I just redid my crossslide screw on my
Atlas 10".  I made both the screw and the nut.  The screw was from
1/2" hardened and ground shaft stock, and was very difficult to cut.
The nut was brass, I made it a little longer than the original.  I hand
fit the acme thread in the nut, until it was a very close fit to the
screw.  It works very well, except for one thing.  When I took it apart
to measure the worn screw and nut, I never noticed it was LEFT hand
thread!  So, out of habit, I cut a RIGHT hand thread.  Now, the lathe
crossslide turns backwards from how it used to go!  Oops - one of these
days that is going to make a big screwup, when something goes wrong, and
I want to get the tool out of whatever is in the lathe quickly, and I turn
the wrong way out of habit!  I'll have to make a new screw and nut, but
not right now.

Anyway, I used a slim boring bar with changable steel tool bits, and I cut
an Acme threading bit for it.  It went quite well, compared to the trouble
with the hardened screw material.  I made the whole nut in about 4 hours.
Now I have the boring bar, which can be used for many internal boring
jobs, whereas the Acme tap is a pretty specific tool.

						Jon