[Florinbv]

Hello,

I want to make a thread relief like in the picture bellow, using a cnc lathe, but i dont know how to do it, can you please advise with a solution?

Many thanks!

[Tarzan63]

You can make that with a groove tool that is as wide or wider than the lead of the thread(I.e.- 12 TPI = .0833333 for example.
So copy your thread cycle, then past it into the new tool. Change the spindle speed to a slow speed compared to the speed you threaded it at.
So if you ran the thread at 300 rpm, maybe run the groove tool at maybe 100rpm. The slower the rpm the shorter the ramp. Another tip, you want the machine in full rapid for the groove tool. That will determine the ramp angle too.

In your Groove tool cycle, change your Z to go the desired distance. On a 12TPI thread I would try z-.1 to start. Make sure you have the same Z start point for both tools. That is critical to sync the thread with the deburr process.

BTW, this is called a "blunt start thread" or "higby" thread. There are thread one the internet about it.

Good luck, it's pretty simple once you try it.

- - - Updated - - -

You can make that with a groove tool that is as wide or wider than the lead of the thread(I.e.- 12 TPI = .0833333 for example.
So copy your thread cycle, then past it into the new tool. Change the spindle speed to a slow speed compared to the speed you threaded it at.
So if you ran the thread at 300 rpm, maybe run the groove tool at maybe 100rpm. The slower the rpm the shorter the ramp. Another tip, you want the machine in full rapid for the groove tool. That will determine the ramp angle too.

In your Groove tool cycle, change your Z to go the desired distance. On a 12TPI thread I would try z-.1 to start. Make sure you have the same Z start point for both tools. That is critical to sync the thread with the deburr process.

BTW, this is called a "blunt start thread" or "higby" thread. There are thread one the internet about it.

Good luck, it's pretty simple once you try it.

[Florinbv]

Many thanks!!!