The following is a guide for designing gears in sketchup for 3D
printing, CNC milling or similar. For a good introduction in
general gear design see here. For an introduction to sketchup
see the sketchup related links this page. A collection of the
gears seen in this page can be downloaded from the 3d warehouse.
To begin with, download the involute gear plugin and copy it to
your sketchup plugin directory. This plug-in was not produced by
me and all credit goes to Cadalog Inc for writing this very
useful tool. Then open sketchup and choose ‘Involute Gear’ from
the draw menu. From the dialogue box you are presented with
three options. Number of Teeth. The number of teeth on your
small gear (pinion gear) relative to your large gear (gear
wheel) will determine the gear ratio. If you desire a gear ratio
of 2:1 then your gear wheel will have twice as many teeth as
your pinion. However, your gear with more teeth would need need
to be twice the size in order to have the same sized teeth. By
choosing an even number o