Drilling the center most of the way through and grinding or chiseling the head off, then punching the left overs out works most every time.
Personally I have a 14" long cold chisel about 1" wide, and a big hammer. I knock the head off with a few good swings, and then a sturdy punch will pop the rivet out. I find this method to be much faster than any others. But if removing more than a dozen or so at one sitting you may not like it. I was working on my truck in a place with no power or air, so the chisel was the only method available, I was very surprised to find it worked so well and fast.
I have tried the air chisel, and it is not as fast as my hammer and chisel, and damages the frame more. The air tool with a punch in it is very handy for punching them out after the head is removed with another method.
If you can't chisel the entire head off at once grinding an X in it with a cut off wheel will help.
Grigg
