This definitely sounds like homework to me. IIRC, this is straight out
of a Mech Eng 101 text book! It's probably already been done so take a
look in "Machinery's Handbook" or "Engineering Formulas" which are both
standard text books from Industrial Press Inc that are commonly used in
mech-tech programs.

In your scenario, gearA should always be the 'drive gear'. GearB should
always be 'driven' by gearA. GearC should always be 'driven' by gearB.
You should be able to switch them around at will and your formulas
adjust accordingly. If you set your worksheet up so the pitch (num
teeth) are in named cells then your formulas can ref those for any
combination. Design the formulas to calc number of turns for B[C] to 1
turn A.

Back in the day.., we would attach degree wheels to the gears and take
readings at the marker position for each at whatever degree of
revolution of the drive gear we chose/needed. Now, my CAD software
computes this automatically and so after using it for over 20 years
I've forgotten the formulas we used prior to using degree wheels. I
suppose I could look them up but, since you are going to do that now
anyway<g...

--
Garry

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