About this 3D model

I decided that the timing belt gear in my plastruder was just too unreliable, so I wanted to try out a worm gear drive cog like I'd seen others have good success with. I have a cheap 9x20 lathe and a tap set, but I was missing something to hold the gear blank to the tap while letting it rotate. So I fabbed one. This isn't a robust thing, but it's good enough, and I've been able to make several small brass worm gears with it.