Karl Townsend wrote:
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



The Bridgeport 1J and 2J use 2 stages. There is a toothed belt with a
small sprocket on the driven pulley and a great big sprocket behind it
that turns the back gear's pinion. Then, the pinion turns the big
bull gear below the driven pulley. The center of the bull gear is the
female spline that drives the spindle spline.

Jon