Gear reduction question

[Specialagentjim]

Originally posted by dmellich
If two gears/pulleys, different sizes say 60 teeth and 20 teeth are sitting on the same shaft next to each other, is there a reduction factor between them? If so, how is that factor used with other reductions being used? Are they multiplied or added? Thanks for any help.
David M. Ellich

The way I figure these is I look at the rotations. If you have a 40 tooth gear interacting with a 20 tooth, which is on the same axis shaft as the 60, which is interacting wtih a 120, you would have:

40 teeth to 20 teeth = 1 turn of the first shaft results in 2 turns of the second.

Now your going from 2 turns from a 60 tooth shaft to 4 turns on the 120 tooth gear.

i think i did this right...although, i am doing this last minute at my grandfathers house...so if im not right id love to be corrected..If I get time when i get home, ill put some 3ds images up.