Help with drill-Mill conversion

**John S** · 29-06-2009

Screws are 5/8" x 10 tpi not metric,
Unfortunately 5/8" usually comes in 8 tpi.

Is it definitely an Acme screw or square thread, acme has tapered sides at 29 degrees ?

Then are they both RH, LH or one of each.

**Ross77** · 29-06-2009

Screws are 5/8" x 10 tpi not metric,
Unfortunately 5/8" usually comes in 8 tpi.

Is it definitely an Acme screw or square thread, acme has tapered sides at 29 degrees ?

Then are they both RH, LH or one of each.

Bugger.. I thouht Acme was square, and trapazoidal had the taper?

Anyway they are square and both RH, y axis moves correct but the x is opposite to the lathe (clockwise rotation moves it towards you)

**John S** · 30-06-2009

Square is square.
Acme is 29 degrees and usually imperial [ not always ]
Trapezoidal is 30 degrees and always metric

Let me have a look tomorrow to see what taps I have, definitely got 5/8" x 8 LH Acme but not sure on the rest.
.