Waterjet works quite well for making gears to reasonable precision (say
+/- 0.002 or 0.003" or so.) Better precision is possible with the
higher-end machines with careful setup and such.

See: http://www.waterjets.org/waterjet_pictures_5.html for a few
examples.

Also, scroll down about a 3rd of the way down the following page for
lots of examples of waterjet gears in various materials, and the
software used to program them, and some other info and such:

http://www.omax.com/support/pics_from_cd/Pictures.html

The kind of accuracy you can get will be HIGHLY dependant on the brand
of equipment used.

A machine for doing the above work can be had for $80,000 (a 24 x 24"
machine)

Carl.

daniel peterman wrote:
Seems like waterjet would be ideal for short runs of gears since they
are basically flat. Here's a crazy idea... How about cutting the change
gears from phenolic using a laser. Would they be tough enough?
On modern CNC equipment would they just make a single gear when one is
ordered or run a batch of say, 6, and save the rest for future orders?
Not much material in a gear so they wouldn't take up much space to store
in case another order came in next week. I would never make just one of
anything if making more only used another 3 bucks worth of material and
10 bucks labor.