Hard time finding inserts and holders 10 tpi LH ACME

I'm wondering if the screws are metric sizes, if so it is possible that they may be threaded in the metric trapezoidal thread, which is 30 degree included angle rather than 29 degree that Acme uses. Best to make sure before ordering inserts, probably more practical to grind HSS tools for one off projects.
 
The measured value with the caliper is curiously close to 20mm in diameter. 0.7945" = 20.18mm.
Maybe there was crud on the screw, or caliper, or it hadn't been zeroed recently. I know the cheap calipers aren't that great holding zero, from personal experience. I trust a micrometer, not so much a digital caliper.
 
benmychree said:
I'm wondering if the screws are metric sizes, if so it is possible that they may be threaded in the metric trapezoidal thread, which is 30 degree included angle rather than 29 degree that Acme uses. Best to make sure before ordering inserts, probably more practical to grind HSS tools for one off projects.
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I was wondering this too, but the supplier did say Acme, and if he's doing both parts it's a wash.
 
mac1911 said:
Im looking for 10 tpi acme left hand internal and external inserts and holder.
I have a AXA qctp.

I need to attempt to make new cross feed and lead screw nuts
Supplier ( smithy ) lathes could not give me specs other than 10 tpi acme. Poking around it seems the screws are odd size or more likely metric cut with 10 tpi pitch? This is the lead screw nut im attempting to make. No longer Available from smithy
View attachment 480064
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Grind your own. Use a boring bar
 
benmychree said:
I'm wondering if the screws are metric sizes, if so it is possible that they may be threaded in the metric trapezoidal thread, which is 30 degree included angle rather than 29 degree that Acme uses. Best to make sure before ordering inserts, probably more practical to grind HSS tools for one off projects.
Click to expand...
Im thinking anythings possible since all Smithy could tell me is 10 tpi ACME but who knows. Could just be 10 tpi whatever thread style.
I suppose I would need a gauge?
The weekend is over for me. I will get back to it some other weekend.
 
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One of the largest threads ever on this project is on this site. It is called Evanut

Search site for it.
The thread tells how to make a new nut out of plastic .

I made one using a plastic cutting board for material that I got from Walmart for a couple bucks.

You heat your lead screw and form plastic around it.

You end up with a formed thread. With no slop.
 
Jimsehr said:
One of the largest threads ever on this project is on this site. It is called Evanut

Search site for it.
The thread tells how to make a new nut out of plastic .

I made one using a plastic cutting board for material that I got from Walmart for a couple bucks.

You heat your lead screw and form plastic around it.

You end up with a formed thread. With no slop.
Click to expand...
Might go that route. Since most of my possible repairs need a second lathe, lol
Another issue is I dont get alot of time on the lathe. Its in a unheated shed so fair weather only use
20-30 hours tops a season , lol
 
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I crashed the compound on my Polish made Summit, bending the lead screw. Had to make a new one. It was imperial lead, as in tpi, but metric OD and trapezoidal form, with metric treads on the bearing retainers.

Greg
 
f350ca said:
I crashed the compound on my Polish made Summit, bending the lead screw. Had to make a new one. It was imperial lead, as in tpi, but metric OD and trapezoidal form, with metric treads on the bearing retainers.

Greg
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This doesn't surprise me at all. 10 tpi for the north American market, trapezoidal thread form because they don't do Acme. No one will be any the wiser for 50+ years.
 
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