I have a machine which has four sequential cog wheels in constant mesh.
The largest cog has 21 teeth and the others have 17, 12 and 10 respectively.
What is the fewest number of revolutions the largest cog must make so that all of the cogs are back
in their starting position?
July 11th, 2012 | Category: 
97.14 (LCD of 17,12 and 10 divided by 21)
Nope, that’s not it, keep trying.
The largest cog must take 340 revolutions