Greetings.  Stock Drive Products Inc. has lots of gears and timing
pulleys, etc. etc.  They are online and have catalogs of parts in both
metric and English units.  Some stuff is a little expensive but the
service is excellent.  You can buy single quantities and minimum order
is just $30 or so.

I believe that their gears are of their own manufacture, but they have
a complete line of all the "stock" stuff, hence the name.  Quality is
excellent for what I have bought.

Best regards,
Spencer Chase
Laytonville, Calif.
http://www.spencerserolls.com/