two older gentlemen that I have talked to said that auto parts machine shops used to "shim the brake shoes" when replacing the drums was not an option. Im assuming that this meant they would place shim stock underneath the pad of the shoe and then rivet the shoe material over the shim stock.
That would be incredibly unsafe. The thinner the walls of the brake drum get, the more likely it is to heat up causing the brakes to fade. Get it thin enough and it could actually shatter.
I don't doubt some used to do that, but you'd go to jail for doing it now.
