For precision sanding and grinding, a 2″ Roloc disc is hard to beat. A built-in screw secures the disc to the sanding pad. Sanding discs are available from 24 to 240 grit. Scotch-Brite discs are also available. I’ve seen the sanding pads and abrasive assortments at the big box stores, but they are much cheaper at an industrial supplier.