I've always wondered why coffee grinders were square. Round would be easier to grip, truthful in form to its rotating parts and just overall better looking. So today I made one out of scraps of walnut.
The conventional one at right from which I scavenged the parts.
The construction uses a 4" and 3" hole saw and then the parts are glued together.
Oh, and they aren't round because it's a heck of a lot easier to make a square one.