ef-48/72: drive wheel

What do you do when you don't have any 4" diameter round stock? You cut a drive wheel out of a square block of aluminum and true it on the lathe. Ream the hole for the motor shaft, drill and tap for a set screw, and you've got a partially completed drive wheel (minus the interior recess and crowned surface).

I'm in the process of making some molds to cast some 4" diameter billets so I don't have to do this again. I should have enough extra for anyone looking to build a grinder (I think E should be starting one in the near future).