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Finish quality with lathe tool bit

I don't pull back the compound either, but I pull the cross slide with no relief groove all the time. Usually people who watch me do it, at the speed I do it, think I'm crazy. No one else I ever worked with would try it, heh. I usually set an indicator at the left end of the carriage so that my pull point is at one full needle revolution. But if I am allowed a relief groove, I'll use it.
The reasom brought up thread end stopping was that the Op said
" speed slow as the thread runs up to a shoulder."
He did not say how tall a shoulder, or how slow was slow.
I suspect one can go too slow
I believe the Op is using simple HSS tool bits.
Positive side cutting edge and positive back rake. With 10* clearance My advice.
Just positive back rake of 10* off the point would be an improvement
With some lube…
Infeed @ 29 / 30 best for less cutting pressure.
Give it a little top rake and speed up the cut a bit and give it a squirt of cuttin' erl, maybe that sulfur stuff that plumbers use. That should give you a start. You're coming in at a 30 (29.5*), right ? so don't need to think about the v, you'll only be cutting on the leading edge, if that's why you have no top rake.

And you can run up to a shoulder reasonably quick, just have your hand ready :)
I was threading up to a shoulder once and after several scary passes, the mating thread fit nicely. I figured it was a done part but maybe just one more pass to possibly get a better finish. I guess I was a bit slow disengageing the lead screw. Things really go downhill in a hurry when you realize that the clutch handle can't be lifted and it's a twenty five HP motor. It's a real cascade of bad things, all happening in two seconds.
Don’t let it ruin your nerve, and don’t do that again. There are have been several good ways to make “ to shoulder “ work explained here . Adopt one or more of them , and PAY ATTENTION. You can practice pulling out on an indicator in open air at very high speed, you might be surprised how on the mark fast you can be. Back to work now. Every Machinist makes mistakes, a pro knows how to fix them.
Post #9 is much better, but still very poor.

For steel and aluminum threading and turning a positive top rake and a positive side cutting rake are best. And only cutting on one side of the bit/insert, not both sides.
Going straight in with the cross feed or compound makes the bit/insert cuts on both side of the bit/inset so it is too big of a cut. And one side of the bit/insert has the wrong rake angle.
Threading to toward the left the rake should be positive to that direction.

It is like a shovel; the blade gets under the load. if the blade was a flat nose it would just push the load compacting it to itself and just stop the shovel.
A tool bit just pushing begins to chatter
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