Thread Rolling on 316 Stainless Steel - What Process is Best?

[relylok]

Hi Folks

We are manufacturing Instrumentation Fittings in 316 Stainless Steel. We are cutting threads using lathes & turret lathes. The threads range from 1/8" to 1"NPT/BSP Taper/BSP Parallel & 10-32 UNF to 1-5/16"-20 UN. Metric sizes fom M8-1.0 to M24-1.5 are also used.
We are considering moving to thread rolling but are not able to decide between thread rolling machinery or rolling with Fette or C.J.Winter type rolling attachments on our existing Turret Lathes. The turret lathes we have at present are Herbert No.4 models.
Could anyone let us know the pros and cons of opting for thread rolling and which system to go with ?

Thanks
Ashim Kumar

[Jim Wynne]

I started a new thread with this post, because it was off-topic in the thread it was originally posted in.

[Jennifer Kirley]

Originally Posted by Jim Wynne

I started a new thread with this post, because it was off-topic in the thread it was originally posted in.

Ack! That explains why I just replied to a 2002 thread.

[Jim Wynne]

Originally Posted by Jennifer Kirley

Ack! That explains why I just replied to a 2002 thread.

It doesn't make any difference how old the thread is, if you have something of interest to add. A lot of people learn from reading the old threads, and sometimes it's good to have some one bump one up with new information.

[Jennifer Kirley]

Originally Posted by Jim Wynne

It doesn't make any difference how old the thread is, if you have something of interest to add. A lot of people learn from reading the old threads, and sometimes it's good to have some one bump one up with new information.

I'm leaving my post there because I agree with you. I got a Twilight Zone feeling when the thread's recent post disappeared, so it's nice to learn why that happened, and I'm not just seeing things.

[JRKH]

Originally Posted by relylok

Hi Folks

We are manufacturing Instrumentation Fittings in 316 Stainless Steel. We are cutting threads using lathes & turret lathes. The threads range from 1/8" to 1"NPT/BSP Taper/BSP Parallel & 10-32 UNF to 1-5/16"-20 UN. Metric sizes fom M8-1.0 to M24-1.5 are also used.
We are considering moving to thread rolling but are not able to decide between thread rolling machinery or rolling with Fette or C.J.Winter type rolling attachments on our existing Turret Lathes. The turret lathes we have at present are Herbert No.4 models.
Could anyone let us know the pros and cons of opting for thread rolling and which system to go with ?

Thanks
Ashim Kumar

In my experience thread rolling on 316 stainless is not a problem. If I remember correctly we had to slow our speed down a bit but it was still much faster and cleaner than thread chasing. We did all our thread rolling in our turret lathes (Warner Swasey No 3's and 4's) since we were generally machining the ends to size before threading.
I had no experience with rolling tapered threads and so cannot speak to that. However you should not have problems with the straight threads. Just remember that with thread rolling the process is more sensitive to changes in the dia before rolling. The rule of thumb was that each .001 inch change in blank dia woudl result in .003 change in thread height. I busted a few thread rollers in my day by letting the dia get too large.
As for the specific brands of rollers, I cannot directly speak to that. I believe we used Acme but again that was close to 20 years ago. On the whole I think you'll be very pleased with the increase thread quality as well as a reduction in cycle time.

It has been many years since I did any thread rolling so there may be newer and better answers out there.

Hope this helps

James