On Sat, 05 Apr 2008 09:21:59 -0400, Bill Schwab
wrote:



However, all of this depends on a reliable zero location. Short of
chucking something of known diameter, or turning and measuring same, I
am not sure how to get such a reference. It seems it would be blown
away by any adjustment of the toolpost???

Yup. A good QC toolpost as Aloris helps, but generally when a
toolchange is made then I take a light cut with the new tool, measure
the workpiece, set the dials to agree with the measurement and
proceed.

If I'm after accurate threads I'll wipe a bit of toolmaker's blue on
the work and sneak up on it with the threading tool until it "marks",
then set the dials accordingly.

I'm sure my approach is very "old school". I am an amateur, by no
means a professional machinist. That said, I would not expect the
absolute accuracy/repeatability of a CNC lathe from a
much-less-costly manual lathe. And, I imagine there's a certain
amount of "fartin' around" necessary to set up a CNC lathe for a given
job. Since I rarely make more than 1 of anything, I just do the
fartin' around along the way rather than all up front.