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View Full Version : thread rolling - 3 vs. 2 rollers?



TRX
11-06-2012, 09:30 AM
I've used a thread roller before. That one had three rolls you mounted in the head, you put it in the tailstock turret, and ran it up onto the workpiece. No problemo.

Looking through "thread rollers" on eBay, I've seeing a bunch of two-roll tools that look like "nutcracker" knurling tools. They look like they go onto a lathe toolpost.

How do those work? I'm assuming you run them onto the workpiece from the end like a 3-roll head, but what keeps the workpiece from just popping through to the other side? A blank idler roll or adjustable backstop?

wierdscience
11-06-2012, 10:11 AM
Tangential thread rolling in action-

https://www.youtube.com/watch?v=RNTTUvK9Lb0

TRX
11-06-2012, 06:41 PM
So... you just run the tool across the part, then back it out?

wierdscience
11-06-2012, 07:59 PM
Just like the video,the tool plunges in like a parting tool and then pulls back.Used to have one on a small turret lathe,they are best suited for threads the width of the dies or less.

TRX
11-06-2012, 09:25 PM
There's no stop? It goes over-center and then comes back?

Are the rolls geared together?

wierdscience
11-06-2012, 11:20 PM
There's no stop? It goes over-center and then comes back?

Are the rolls geared together?

Yes,they need to stop on center or slightly before.

Yes the Dies are geared together,each Die has a shoulder and in that shoulder is a slot.That slot engages a timing pin in each shaft.

TRX
11-09-2012, 03:37 PM
How do you adjust the size of the thread? Or is the tip and root diameter ground into the rollers?

wierdscience
11-09-2012, 10:42 PM
The roller arms adjust like a scissor knurling tool.See more detail here-
http://www.rsvptooling.com/rt10.html

My suggestion is give RSVP a call,tell them what you are doing and see what they have to offer.

TRX
11-10-2012, 05:16 AM
Ah! Thanks! There's a link there to a Fette setup manual. And the keyword I needed to find other setup information on the web is "tangential". Otherwise I just got 3-die heads.