I've got a 1" travel dial indicator set up on the lathe to measure carriage position. I set the indicator so it reads, say, 0.500" when the carriage is at the end of the cut (i.e. end of the thread). I cut threads in slowest backgear (about 60 rpm), and I find it's fairly easy to watch the needle revolutions go 0, 0.100, 0.200, ...0.500, then:
1) Flip the halfnut lever to disengage the carriage and simultaneously
2) Wind out the tool with the cross slide feedscrew
I find I can stop within a thou or two of the same spot without much trouble.
This assumes you have a threading dial so you don't need to keep the halfnuts engaged to maintain the gearing relationship, of course.
[This message has been edited by SGW (edited 11-16-2001).]
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