I need to know the exact back gear ratio for Bridgeport Series II
Interact 2. I need to know it exactly, because I need it for rigid
tapping.

I know that it is between 8.2 and 8.42 from just looking at my dial, but I need to know the exact value, not approximate.

The specs on my spec sheet say 8.3:1 ratio, but I am not totally sure if this is this ratio exactly or approximately (as in teeth ratio).

http://igor.chudov.com/projects/Bridgeport-Series-II-Interact-2-CNC-Mill/specs.jpg

Thanks

I know that it is between 8.2 and 8.42 from just looking at my dial, but I need to know the exact value, not approximate.

The specs on my spec sheet say 8.3:1 ratio, but I am not totally sure if this is this ratio exactly or approximately (as in teeth ratio).

http://igor.chudov.com/projects/Bridgeport-Series-II-Interact-2-CNC-Mill/specs.jpg

Thanks