8-32 threads

[Howard Jones]

Hello . I need to turn 5/16 dia 12L14 down to .166 dia X .875 long and cut 8-32 threads into the part. Thread length is 5/8". What speeds and feeds would I use and how much material would I take per pass to keep material from flexing? Have never done threads this small before. Would appreciate help. Cutting on cnc Doosan lathe.

 

[Cole2534]

If you can grip the part very close to the shoulder, I've had luck peeling the diameter in one pass on parts like these.

 

[Guest]

Off the top of my head I would just take one pass at 3,000 RPM at about .002 IPR.

 

[Delw]

this is an easy one.
break the length into 3 parts for example

cut only .300 long for the major, then thread .250 long, then cut the major to .600 long then thread to .550, then cut major to finish length then thread to size.

Make sure you do the Chamfer and face at the very first run, dont do them after.

 

[rcs60]

I think that the answer depends on how you are planning to cut the threads
single point split up the turn and threads to to three passes same answer as DELW

 

[Howard Jones]

Thank you for all the answers. I ended up peeling all the material in one pass. 3000 rpm. F.003

 

[Limy Sami]

Off the top of my head I would just take one pass at 3,000 RPM at about .002 IPR.

And use one of those new fangled die things for the thread.