[regulator]

Does anyone know how to make a simple gear that is about the size of a sprocket.... do you use a cutter, saw, melt it down, ???

[tajcrews]

What are you gonna be using it for? You can buy super cheap cogs from your LBS, well most i would say. Cheap as in $5-10 at most.

[HandsomeRyan]

Originally Posted by regulator

Does anyone know how to make a simple gear that is about the size of a sprocket.... do you use a cutter, saw, melt it down, ???

First: I agree with tajcrews, buying a cog is likely your best bet.

With that said- most modern cogs are made on computer controlled milling machines like this:
YouTube - Making Gears