Karl Townsend wrote:
I'm setting up rigid tapping on my mill. The encoder is ahead of the
backgear so I'm wanting the exact gear ratio. I set up an encoder on both
the shaft before the backgear and at the cutting tool so I could measure the
turns of the spindle down to .01 revolution accuracy and took this data

Turns at tool turns at drive
1 6.1245
8 49.0573
80 490.65
163.050 1000

Is there a math wiz out there that can tell me how many teeth on the drive
gear and how many on the driven gear? (integer ratio of this data)

Karl


The bull gear on a Bridgeport J head has 89 teeth.
(Don't know how many on the pinion.) I had to
count them as I put a gear tooth sensor on it for
tachometer use.

Jon