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Great script, but a few questions:

1) The non-cone intersection cylinder on the large gear trims off a small amount of the large gear OD. Why?

2) As gears are changed, say from 11/45 to 9/47, how does one determine the optimal value to use for the gear separation distance?

3) I understand how the geometry connection tolerances are used, but what do the AT, ST and TT labels stand for?