[joedoh]

man I hate grinding rivets.

for next time,

instead of a grinding disc use a thin cut off wheel in the grinder and be VERY CAREFUL (goggles, face shield, heavy long sleeve shirt, leather gloves, no shorts or flip flops!) to hold the grinder firmly, dont bind the disc or it will explode and the shrapnel is lethal. (maybe not lethal, but it will make you remember the date on the calendar as a BC/AD kind of thing)

slice the heads off the rivets, easy peasy, then drill a hole about half the size of the rivet in the center. the hole in the center takes the compressive force out of the rivet and you should be able to just bang them through.

if you have a plasma cutter, just blow right through the centers of the rivets and blow the heads off sideways, easy peasy.