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1.4375 acme thread possible?

Joined
Jan 12, 2020
Location
Bastrop
I am in the process of making a new lead screw for an old lathe. It is definitely Acme 4tpi and the diameter across threads is 1.429 and the root dia is 1.156”. It seems I cannot find any specs within these measurements for an acme thread. Seems like it’s maybe supposed the be 1-7/16 acme but all literature I have goes from 1-3/8 acme to 1-1/2 acme. Any thoughts?
 
If that is on that old Lehmann lathe, it is 1.4375-4 Acme thread. Used to have a copy of the original drawing on that leadscrew. Lost many years a go. The material they used to use was 1144 TPG or Stressproof. Used to be a place in Dallas that made the leadscrews for Lehmann after they moved from Saint Louis, Mo. Unfortunately, they are no more. They milled the thread on those leadscrews.

Edit: Send me your email and I'll send you a print out of the thread dimensions for that thread. Ken
 
Used to be a place in Dallas that made the leadscrews

On a shop built thread mill

Machine Tool and Repair

Best wire size for 4 pitch will be .12911 - these will be flush with OD (per Van Keuren catalog 31)
 
53D58ABC-DC67-4052-B03D-18CB08C49A85.jpg330527 I’ll be dammned. Sure is. I’ve been in the feed double bevel as it rolled the key finally and leadscrew is jumped on a good portion. Thought I’d fix it all while apart.1520C665-A6CA-49C3-AC20-F92068B5DB0E.jpg bronze miter gear is pretty smoked but it is a weird one. 60 tooth with 5” PD
 

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Used to have a bunch of those bronze bevel gears with all sorts of wear on hand. Don't remember what happen to them.

EDIT: TexasAggie, John doesn't know it, he has the bevel gear cutters that was used at one time for cutting the teeth on that bronze gear. That's if John still has all of them gear cutters my family donated to his shop many years ago.

Ken
 
On a shop built thread mill

Machine Tool and Repair

Best wire size for 4 pitch will be .12911 - these will be flush with OD (per Van Keuren catalog 31)

John,

That thread mill Machine Tool & Repair had was made by a company called "SHIELDS". I don't know if you remember, we had one just like it, way back in time that sat in the yard by the old planer you bought from us.
 
That bronze gear is factory huh. Mine almost shot tempted to try and make a new one or remake entire bevel with off the shelf parts with same ratio.

Got feed shaft keyway welded up about to mill it on k&t 4H 87C4F283-D87B-4256-B200-C476C79EC839.jpg7FAE4EC3-B92A-4A79-91DC-EB42D0EBF2F6.jpgD79DAF54-BD9A-42DA-BDCE-143200C316C4.jpg5B176D91-5E54-4672-93DB-EF153612C455.jpg2F0FA068-BB2F-4341-A9AE-90F407BA4642.jpg
 
Have Ken's old folder on his 18" X 11 foot lathe - serial 1243 - it has two lead screw drawings at least - 1202 - C and one unreadable

Both have a 3/4 thread on the end, one 10 pitch and one 16 pitch

The wire size on 1202-C is given as .125 and the dwg specifies ONE wire with a measurement of 1.447 / 1.445 over that one wire

Material was given as 1040 ground stock 1 7/16 O.D.

Length was 9 foot 5 1/4" for that 11 foot bed

Some pictures

20211002_131617.jpg20211002_131629.jpg
 








 
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