How to make TR14 trapezoidal threads...Tooling?

[rfrink]

Hello! I've attached a photo. I do not have experience with these threads and I'm not totally sure what I have here. It is a power screw for a linear actuator and I need to make new nuts.

It was made in Italy and it seems to be ISO so I think the threads are TR14 rather than acme. The nominal OD of the screw is about 14mm. It has 2 starts.

I can do this in a CNC lathe or in a VMC. I'm having troubles finding the tooling. Either a thread mill, or single point tool for the lathe.

Anyone familiar with this thread and willing to offer advice?

In the photo, you will see the screw and black nut made from plastic. We want to make new nuts from 12L14 steel. I'll make about 12 nuts.

Thanks!!!

click image to view

 

[gregormarwick]

TR, like acme, cannot be threadmilled correctly at common (leadscrew) sizes in a normal 3 axis configuration. You need to screwcut it or tap it.

Tooling should be readily available however.

If you go looking for a tap, the correct designation for trapezoidal is Tr<dia> x <lead> (<pitch>), eg. Tr14 x 8 (P4) for a two start 4mm pitch.

If you decide to screwcut, all the big names do trapezoidal inserts, but you will likely have to go with a solid carbide bar because of the small diameter. Horn and Sandvik for sure have solid Tr tools.

 

[rfrink]

Thank you very much for the info! I have determined that the thread is a TR14 X 8(p4) RH. The pitch is 4mm and the lead is 8mm/rev.

Now, my challenge is to find tooling! Ive searched the web and cannot find a tap or a single point thread tool for the lathe. I have a few inquiries out there but nothing yet.