Mini Drum Sander

This is a mini drum sander that I'm working on that will allow me to sand small parts with just the power of my impact driver/hand drill.

The design is centered around using a 1/4 sheet to optimize paper usage. The sheet is wrapped around the drum and then a wedge of some sort (still need to figure out the wedge a bit) is shoved into the slot in the drum to hold it taut.

Parts:
2 Walls
2 Bearing Clamps
2 Bearings 1/2"ID 1-1/8"OD x 5/16 thickness
1 Shelf
1 Drum
1 Hex Drive
A ton of various length 10-32 or 10-24 bolts and appropriate washers
A (recommending plywood) base to screw the walls to

Current concerns:
1- I've left 5-thou tolerances in most places which I'm hoping is the right amount for no slop, but also, if things are a bit off level between the drum and the bearings, one could strategically place some blue-tape around parts of the bearings to raise one side by a few thou to help level as needed.
2- Although using the hex-drive is handy as it means you don't