I am just getting started with stone setting, and have a question about the use of stone setting burrs.
I have a selection of Busch burrs.

I'm starting with a drill, then removing the bulk of material with a ball burr, and then attempting to cut the finished seat with either a stone setting burr or a hart burr.

The problem I have, is that the stone setting and hart burrs don't seem to cut! It almost feels like they are permanently clogged up, and all they seem to do is polish the metal and get very hot.

I am using "cut lube" on all burrs, as recommended by Cookson, and have also tried beeswax. My material is sterling silver.

What am I doing wrong?