Forum member Gus has done it a couple of times and posted it, his most recent was the feed motor for his mill. I believe that the hardest part is to get the correct blank size for the number of teeth that you want.
This is a great way to make a rack and pinion, I have made these a number of times, the pitch circle seems to sort itself out and you can use a length of studding the same size as the tap for the driver.