Step by step,
how would be the best way
to use a rotary tool
to remove a ridge,
and what would be the ideal
flap or grinding wheel
to use in the tool?

Should one try to totally remove the ridge,
or just remove emough material to allow the piston rings to compress and pass over a reduced ridge?

Should one strive to keep
the centerline of the rotary tool parallel to the line of the bore, or should the rotary tool be held at an angle
to grind the original ridge
into a shallow ramp shape?

Since saving the block from damage
that forces an overbore is much desired,
At what level of material removal
should one stop for safety's sake?

Perhaps a shim of a few thousandths thickness
could be held just below the ridge
to keep the rotary tool wheel from accidently
cutting too deep
or too far down?