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From: Snag <Snag_one@msn.com>
Newsgroups: rec.crafts.metalworking
Subject: An answer ...
Date: Tue, 22 Apr 2025 15:41:34 -0500
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    And now I know that the leadscrew is indeed Acme . I mentioned in 
the other thread about making a mold of the threads using a lead ball 
and a c-clamp. Well there ain't enough room under there for a clamp , 
but there is room for a pair of vise grips . And now I have a perfect 
impression of an unworn section of the threads . You can't tell from 
looking at the screw what the profile is . But after forming the lead 
then cutting it with a utility knife blade to see the cross section it's 
definitely acme . I shall be setting up a fixture* to hold a cutter at 
precisely 14.5° on the mill and grinding the profile with my grinding 
disc I bought for the end mill sharpening fixture . I'll need to hold 
the small screwless vise in the mill vise to get a relief angle on the 
cutters . I'll be recutting  another piece of stock - with the proper 
angle and dimensions - as a fit check .
   Clare Snyder and Joe Gwinn were both instrumental in my decision to 
make the lead impression ... Thanks Guys !
   * I'll need to grind both a 3/16" cutter for the boring bar and a 
1/4" for the OD thread . This project needs more precision than I can 
manage freehand . And I'll probably end up making one for the Y axis too .
-- 
Snag
We live in a time where intelligent people
are being silenced so that
stupid people won't be offended.