wrote in message
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I have learned that even when replacing the insert - bushing and washers
the outer circle of the grinding wheel was out of round and need it to be
trued.

If the old bushing was out of round, of course. Couldn't be otherwise.
Actually, if the old one was perfect and the new one isn't, same pertains.

I have had wobbling and out of round problems with wheel made in the
middle east and had to returned them to the industrial supplier. At the
end of the day I invested in a diamond wheel dresser. I have found that
the insert - bushings are made with stamped metal and plastic and the ID
and OD are not concentrically.

When I bought my mandrel, it came with the standard wheels of the day and
some wonderful soft metal (may have been lead, but I'm not telling)
bushings. You could adjust/tighten them with a punch. When new wheels were
installed, first thing I did was put in the old bushings, though the new
appear to be of a polyethylene-type plastic which might also be adjustable
with a punch. .