I agree.. searching for the actual purpose/intent of a short-lived decades
old design feature could result in a huge waste of time.

We'll await the day when someone poses the question: Who was asking about
pins in the bench grinder shaft arbors, because..

All we might do at this point is speculate.. and someone probably nailed it,
as there are always good ideas found here, IMO.

--
WB
..........


"Joseph Gwinn" wrote in message
...
In article ,
"Wild_Bill" wrote:

There doesn't seem to be a good reason for the pins. Maybe the only way
to
find out what problem (real or imagined) Rockwell designers thought they
were addressing, would be to find some advertising literature from the
time
when this type of "feature" was introduced.

Yes, but it seems like a lot of work to find that one ad. Maybe someone
will know where to look.


Putting a thru hole that size in a 1/2" shaft doesn't seem reasonable to
me,
but I assume someone thought it would be a good idea.

Why is a 0.096" diameter hole in a 0.500" shaft a problem? This does
not seem large compared to the shaft.


If there were wrench flats (or pin spanner holes) on the inner wheel
flanges
to fit a wrench when removing and replacing the shaft nuts, I could see
some
perceived practical use for the pins, but then only really useful if the
nuts were nylock types (any type of locking nut is not actually required
for
mounting grinding wheels), because grinding wheel nuts don't require
significant torque to make the mounting secure.

There are no such holes. Just RH and LH 1/2-20 hex nuts.


I've seen used bench grinder arbor threads that have been chewed up by
someone using a plier on them, apparently by someone not smart enough to
figure out the right direction to turn the nuts, or not confident in
having
the nuts just snug enough to firmly secure the grinding wheel.

Yes, but no such damage seen.


I've also seen wheels with significant gouges in them, so if an
accidental
jam on one side caused the motor's rotor to stop, it's possible the other
wheel could continue to rotate, but that's still not likely to unscrew
the
nut from the arbor threads.

This could be - Bubba at work. But I don't see any other evidence. The
wheels are quite worn, one 6" stone being worn to maybe 4", but no big
gouges in stone or metal.

Joe Gwinn