Drawing involute gear teeth can be a complicated process. Fortunately they have tutorials on how to do this online. There are formulas for this in Earle Buckinham's Analytical mechanics of gears. This was first in the 1950 edition. You can also find a detailed process of this at
. http://docs.google.com/gview?a=v&q=cache:_1PagdvvkVQJ:www.salemcompany.com/cgi-bin/Store/pdfs/InvGrsClSect5Ed2p77-80.pdf+drawing+involute+gear+teeth&hl=en&gl=us.
