If you need to save the mounting you can use a chasing tool. I
modified one so that it has a recess where there would normally be
interference with the closer channel rail, kinda hooks over the rail.
So that you reach over the closer rail and drive into the inner side
of the far rail. This lets you get an angle of attack that’s close to
parallel with the tables, so you have less chance of chipping stones.
You’d need an engravers’ block or a benchmate to hold the ring as
this is a two handed operation. I’ve seen people use a prong lifter
but my feeling is why deal with those nasty tool marks if you don’t
If you do not need to save the mounting a cut off wheel makes quick
work of it. Sometimes just cut thru the shank and gently twist the