Quote Originally Posted by Hans Pearson View Post
The title is misleading, but a rack does have straight teeth. The way a gear exits a rack is slightly different to the way two gears part. I unwittlingly cut a rack with an involute cutter, and I promise you, it does not work well.
A rack is just a gear with infinite radius. The same rules apply. It requires an involute shape like any gear, it is just that the involute surface is straight in this case.