My bet is that it's a 6.125 ratio.. Note it's NOT prime but neither is my
Bridgeport (it's 8.25)


I'm certain its slightly different from 6.125, that was my first estimate.
This is (6.125*4000*100) = 2,450,000 counts. I had 1765 counts more than
this in 100 turns, or nearly 1/2 a revolution of the spindle.

The machine is an Excello model 602. An Excello looks like a bridgeport J
head on steroids. Made in Canada. I've never found a manual for it.

Karl

Sorry to reply to my own post. I used Excel to follow this idea. 31*6.1294 =
190.01 or almost identical to my measuremnets.

I've never had a 1J style head apart. Any chance they use gears with this
many teeth, 31 driving 190?

Karl