When I was a kid I bored both single cylinder Briggs & Stratton and
four cylinder Crosleys on my Dad's 11" South Bend. It was quite an
exercise as the boring bar he had was simply a big stout boring bar
with not calibrations. You adjusted the bar by loosening the tool and
tapping it gently then made a test cut. Usually took a couple of
evenings to do a Crosley to +/-.0005. I have some Crosley engines to
do right now and you can bet I will be doing them on a Bridgeport type
mill. They don't work well with the standard automotive boring bars as
they have nondetachable heads and you have to have a rigid downstop.
BTW: To the fellow that suggested you use a boring bar sysem that
locates on the top deck of the engine, NO WAY! Good boring machines
locate on the crankshaft centerline. To answer the original poster's
question; a vertical mill is not the machine to bore engines on.
Leigh at MarMachine