"DoN. Nichols" wrote in message
...
In article ,
Mike Henry wrote:

"DoN. Nichols" wrote in message
...

[ ... ]

An alternative (not cheap) would be to get one of the Shooting
Star DROs and mount it to the lathe to read off your position precisely,
independent of the accuracy of the leadscrew. It might work out to be
more economical for you than the leadscrew.

A potential problem with the Shooting Star, good as they are, is that the
resolution is 0.0005", which is doubled to 0.001" for diameter
measurements. That's probably good enough for most work, but makes it
hard
to sneak up on a really tight tolerance. The dial indicator would still
work of course. For the longitudinal axis I've been finding a Trav-a-dial
really handy, especially when turning or threading to a shoulder. It's
muc
easier for me to track an analog dial by eye than a digital display.

Hmm ... as long as you aren't turning to a shoulder at the same
time, try using the compound. Set it as close as you can to 5 degrees
44 minutes 21 seconds (5.7392 degrees decimal), and for every 1.000" you
crank in on the compound, you will move in only 0.100", so you can
easily crank in 0.0001" real diameter (with 0.001" on the compound
dial.)

Note that is 5.7392 degrees from parallel to the axis of the
lathe. Some compounds are marked in degrees from parallel, others in
degrees from at right angles to the axis.

I've used that technique before with good results. It doesn't help much
with power feed or threading though g and that's where I like the
Trav-a-dial.

Another benefit from most DROs is that they have a button to
read out diameter removed instead of radius removed, while the
longitudinal feed continues to read directly in length.

The Shooting Star has that feature, but the resolution of the
encoder/electronics is still the same - 0.0005". Switch the display to
diameter and the Y-axis display increments by 0.001" instead of 0.0005".
The compound trick above will get you to tenths, but then the DRO is not
reflecting the turned dimension. It's possible to keep track manually, of
course, but the more things I have to keep track of the more mistakes I
make. That's just me, though.

Mike