I ended up using a dremel tool on one about a month ago. I used the big ( 1.75") cutting wheel and sliced downward, about an 1/8" to the side of the shaft. I only had to cut about half way, the carefully tapped a straight blade screwdriver into the notch I had cut. When I pulled the screwdriver out the plate slipped off with it.
NRA Lifer / Member TSRA