Hi, Simpson36,
Thanks for you inputs. I'll answer one at a time.
Bob,
Couple tips . . .
To reduce the power needed and the flex on your single point cuts:
1) Sharpen the tool. Your photo shows a tool sharpened with a pretty rough wheel. You need a razor edge and a min 7 degree negative rake for that brass. While it is not a necessity, but you could benefit from using some cutting fluid also.
The tool is a brazed carbide cutter (not that negates what you're saying), and that's the way it came. I didn't attempt to sharpen it, but have gotten some diamond polishing stones so that I can try. I do use cutting fluid (Tap Magic), but usually make a point to clean it up before photos.
2) increase the spindle speed . . . a lot . . . . I mean . . . . a LOT
That's where this all started, wondering whether or not my wimpy steppers were able to keep up with faster spindle speeds. They aren't. But I wanted to make sure I could thread slowly with light cuts so I didn't blow $500 on better steppers and drivers only to find it still didn't work. I have confidence I can get the more macho steppers and go faster now.
Having said that, I'm a hobbyist and if I my lathe takes 2 minutes to cut a thread rather than 30 seconds, I really don't care. A lathe doesn't seem very practical to me for things I can go get in the hardware store. If I need some 1/4-20 screws, I'll go buy them. I have some things that I will probably want to thread, but they're things I can't just go get, or get a tap and die for, like camera filter sizes. If I need to thread a portion of some other assembly I'm making I want to be sure I can do that. It isn't my main interest.
3) I don't know how the wizards or the Gcode macros function, but you can reduce thepower required significantly by only cutting one side of the 'V', if that is doable with the wizard/macro.
For cutting those tiny threads on soft material, unless you are doing it for the pleasure and/or the challenge, you should consider just getting a die holder for your tail stock and cut your threads with a die . . . much easier and faster.
My reference to something like an inch long 2-56 was for emphasis. I have seen the pieces I'm working on deflecting under cutter load and I figure I need to find a way to fix that in the long term. Some day I'll see it for real in a part I care about and want to make sure I can work around the bending.
All the best,
Bob