I got tired of trying the same thing each time and decided to try threading without the crossfeed and just used the infeed to .081 for a 16 thread. It looks a million times better and I can't for the life of me seem to think what I screwed up.
Did I forget something super basic?
Only at first.
That you were no longer at school just playin' wit' yerself!
Once you started cutting it as if you were in an industrial environment where there may BE NO compound rest?
You were out of the woods and got good threads.
Once I left school, all my threads were cut that way.
The compound was no use sitting in the back side of the chip tray 8 feet down the bed.
Foreman wudda thot I was NUTS to ask for another hand, plus myself and either foreman himself on the traveler's pendant or a third man having to stop work to run the overhead crane. We only took the massive 4-way off the topslide to mount the compound about once every week or ten days to cut short tapers.
"Straight in" is fine for threading. As you just proved.
Again.
See also CNC. Your inserted Carbide cutter was MADE for straight-in.
With HSS-Cobalt, I have to grind for it.
Here's a good ALL AROUND video in one go:
Threading on a manual lathe BEST TECHNIQUE EVER !!!! - YouTube
Joe covers the basics:
Always thread AWAY from a "feature" such as a shoulder, flat, or undercut.
Spindle is in reverse.
Tool is "upside down". (unless you have a back toolpost). LH thread is opposite.
No drama. No need of special leadscrew reverse or fancy dog-clutched threading aids or other "special features" on the lathe.
NO NEED to even care what angle the compound is set to.
It is not used.
Cross slide only.
Straight in for each pass.
Any thread form, any included angle in degree the insert was made for.
I say again. No need to MESS with the compound.
You do not even need to HAVE one mounted.
And then.. Joe even goes through use of thread wires.
Bottom line?
-You don't NEED a compound rest.
- You don't NEED Monarch's "ELSR", Hendey's (and many top-end Euro lathe's) one -tooth dog clutch.
- You don't NEED Cazenueve's "special apron" threading system.
- You don't even NEED a modern lathe.
You can do what Joe just demonstrated on any lathe that will not shed-chuck (or collet) when run in reverse.
War One era Niles cone heads with 4-Ways that needed a traveling crane to swap, most of all.
Nothing "special". Works for internal threads to a blind hole's bottom even BETTER. Start down-hole, thread OUTWARD, not INWARD.
Every card-carrying oscillating Richard on the clock did it this way "back in the day" of clumsy old lathes.
"Hobbyists", amateurs, however talented, (or not-so-much?) and their "compound rests" were under some OTHER roof!
The "shoulder" we ran up against if we were distracted cutting a fresh chaw of Union Leader, Red Man, dipping Copenhagen snuff, or lighting-up an Old Gold straight or a Camel?
Ignorant free air.. TS end of the workpiece! No harm done.
That simple.