Hi Ross,

There is a way . At work we have a very expensive machine called a spark eroder. You make a male electrode from a graphite type of material using a cnc miller or std miller. In this case the shape of the tooth on the belt. This is then attached to the eroder, and lowered into the blank gear, and spark eroded to create the negative shape. You can cut square holes this way, or any shape you want.

I had a special hex bolt made this way once. Not really a production volume method though since it takes a while.