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