"Wwj2110" wrote in message
...
Make sure you take a skim cut on the face while you are in the same
setup to insure perpedicularity.

a skim cut will not insure perpindictularity.

best way to get perpindictularity is to indicate the top of the block
prior to
grinding. 0 it out on all 4 corners while spinning the spindle

A skim cut will insure perpendicularity if done while the block is still set
up in a 4 jaw chuck, but the face may or may not be at right angles to the
bore, though still perpendicular, based on the concept that if the
particular lathe has any angular cross slide error, the face can taper.

Indicating existing corners does not guarantee that a bore will be
perpendicular unless the face had been cut after the bore was finished, all
in the same set up. That's what the poster said, and he's right.

Harold