Step 2: We Need Power
Kitchenaid attachments all have a square drive shaft that rotates inside of a cylindrical sleeve. The drive shaft fits into a square socket in the mixer and a set screw holds everything together. I didn't want to feel left out so I decided to emulate this arrangement.
I had a threaded drill attachment that I ground square on one end to fit into the mixer. The other end had a male thread so I drilled and tapped a hole into the shaft of the grinder to accommodate it. I don't have a metal lathe but my friend has a wood lathe that worked just fine for this.