Chainplates

[osteoderm]

I've had great success cleaning up stainless with wet-dry sandpaper. If it's really rough, a Fein or disc sander with 180- or 220-grit to start, but I've had best luck finishing by hand with a succesion of grits, 400 down to 1600. If you keep the grades of paper close each time you change, it's really not as much nad-sanding as you'd think, and the final pickling and buffing with rouge or compound goes really quickly.
Also, always drill any holes after all bends have been made.
Also, for pieces such as backing plates that don't need to look all snazzy, I know a few folks whoswear by acid-resistant stainless boilerplate. I can't recall the numerical alloy grade of the stuff... Doesn't take a polish for damn, but also doesn't rust as quickly as normal 304 or 316.