Some time ago I bought a compound cross slide from a junk dealer. After
disassembly and cleaning off the rust and gunk its now back together. Heres
the problem. One lead screw has 13 TPI and the other 12 TPI. For 1
revolution, the 13 TPI screw will move the slide .077 inch which is the
thread pitch, right. The 12 TPI screw moves the slide .166 inch which is
twice the thread pitch. WHY????
My guess is these are metric threads. Don't know how I'll ever convert
these numbers to something useful. Neither screw has a graduated dial.
Maybe it really is just Junk.
19 years ago