That reminds me,
There is one flaky thing about using a metric pitch machine cutting inch
threads (at least the Russian lathes) & it is that the half nut, on some
pitches, can only be engaged on the exact same unique point on the thread
dial or you might not be in sync with the previous cut. They make it tricky
though by marking the dial like an inch machine so you think you can just
drop it in whenever your number comes by. A colleague of mine ruined a
leadscrew nut for a 5" HBM made from a cu$tom bronze ca$ting due to this.

"Dennis Peterson" wrote in message
...
Dean wrote:
According to the manual the model BD-920N has a 9/16" x 16 TPI leadscrew.
Usually though there is a metric/inch change gear, or on fancy machines
just a selector. I believe the magic gear is a 127 tooth gear (25.4*5 =
127 = zero conversion error).
I have used Russian made all metric machines that cut beautiful inch
pitch threads, and vice versa. It doesn't really matter whether the lead
screw is inch or metric as long as the gear ratio is correct you can cut
any pitch you want. - where it matters is in the cross slide, if you have
a metric dial that sucks.

"Bill Janssen" wrote in message

My Grizzly G0516 is listed as having a 3/4"x10 tpi leadscrew but it is
20mm and 12 tpi. So much for the manual. I had to sort this out so I can
build a thread dial for it.

dp