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ACME thread tooling help please

NewtonPens

Plastic
Joined
Jan 6, 2016
Hi everybody - I make pens - so will only be cutting plastics.
Using a tormach slant pro CNC lathe.

I need to cut acme style threads for a client and I'm looking at this for internal-
Acme Threading Tools - Series 32

And I have this for external-
35214 - ID Threading Tool: SIL0375H11

but I'm having a bad time finding 16 tpi acme inserts for this thing.
Should I look for something else? The thread valley needs to be .050" wide to match his other parts. I was going to run the threads close together to get the final width I need.

I was thinking about using a cutoff tool to cut the external block threads with, and then a grooving tool to do the internal threads, but it's hard to find a cutoff tool that narrow that would also work for me as a regular parting off tool.

I'm open to suggestions.
Thanks
Shawn
 
I have cut lots of acme threads, awhile back I made some changeable arbors for an old table saw, the thread pitch was 12. That is getting pretty fine for an acme thread, but sometimes found on hydraulic cylinders. The thread was very easy to cut due to the shallow depth.
It is easy to grind acme tools for those fine pitches, I think it would be unlikely to find inserts.
 
Hi everybody - I make pens - so will only be cutting plastics.
Using a tormach slant pro CNC lathe.

I need to cut acme style threads for a client and I'm looking at this for internal-
Acme Threading Tools - Series 32

And I have this for external-
35214 - ID Threading Tool: SIL0375H11

but I'm having a bad time finding 16 tpi acme inserts for this thing.
Should I look for something else? The thread valley needs to be .050" wide to match his other parts. I was going to run the threads close together to get the final width I need.

I was thinking about using a cutoff tool to cut the external block threads with, and then a grooving tool to do the internal threads, but it's hard to find a cutoff tool that narrow that would also work for me as a regular parting off tool.

I'm open to suggestions.
Thanks
Shawn

"acme style threads" You don't mention a diameter and ACME 16 TPI is usually used for 1/4".

Metric Tr threads are almost identical with ACME (30º vs 29º). Maybe Tr could be an alternative?

http://f-m-s.dk/3.11.pdf

While you're at it consider Stub Acme and Stub Tr.


You make pens? A picture would be good.
 
Thanks for the replies - sorry I'm slow responding.

yep been making pens a few years now -
newtonpens.com

IMG_20190411_152911.jpg

IMG_20190611_172418.jpg

Okay let me see.
So diameter of the male parts will be .550".

Here's a pic of a pen from a guy who does lots of this stuff. I need to call him actually... X)
He calls it drag cutting, or something like that. I think he makes the tools himself...

block threads.jpg

But as far as my client goes - it's gotta be block threads.
 
If you cant find a tool just grind it from HSS. I've ground plenty of small threading and boring bars from 1/4 carbide and HSS. If you are cutting plastic they will last a lifetime.
 
This thread disappeared "in the crowd". Going back to the OP and reading (don't know why it wasn't caught from the beginning) but who cuts threads in small plastic items? The thread is part of the form.
 
Yes those are block threads, not acme.

As for cutting threads in plastic - what do you mean "who cuts threads in plastic, they're part of the form"??
 
Yes those are block threads, not acme.

As for cutting threads in plastic - what do you mean "who cuts threads in plastic, they're part of the form"??

If the pens are mass produced then a form is used. If "individually" made then cutting is certainly cheaper than a form but makes the pens expensive.

This just under 3 minute video is what I think about re pens.
YouTube
 
Yeah those aren't the kinds of pens I make. :) I cut all my threads with point tools. I'm a guy in a laundry room/shop. No room for injection molding machines. X)
 








 
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