I just bought a 8" grinder with aluminum oxide wheels from Woodcraft
(on sale for $89). Both wheels slightly move side to side when
spinning, perhaps 1/16". I tried putting layers of painter's tape on
the wheel where it rests on the flange. That helped a lot, but does
anyone have a systematic procedure for doing this? I guess I may need
to balance the wheel also. Both wheels (60 and 120 grit) seem to be
circular and in good shape. I found lots of google hits on this, but
most do not apply or I don't have the special equipment needed.
Not unusual with inexpensive grinders and wheels, unfortunately.
If you have a dial indicator check the grinder shafts for excessive
runout. If not OK swap it for another. If OK check the arbor flange.
Many have a stamped steel washer that serves as the arbor flange and
this is probably the source of your problem. It rests on a machined
ridge on the shaft and it's hard to get a good seat. I usually rotate
the flanges independent of the wheel until I find a spot where all the
tolerances stack up in a good way. Sorry way to do things, for sure.
What you shouldn't do is try to true the side of the wheel, that can
What is excessive runout, you ask? Good question. Since any wobble is
amplified by the distance to the wheel OD, I'd shoot for less than
.0015 or so.
Hey, another thing to check is the label. Make sure there isn't a blob
of glue under the label on the sides of the wheels. This usually
squashes down under pressure while mounting the wheel, but you never
know. Wouldn't hurt to check.
Once it's reasonably close (like so it doesn't just walk off the bench
on its own :) ), I don't worry about. All you're doing w/ the grinder
is getting rid of knicks and establishing rough bevel angle, anyway.
Anything of any precision isn't done on a rough grinding wheel, anyway.
$0.02, imo, etc., etc., etc., ...
While it's nice to have them perpendicular to the axis, as long as
they're not out of balance and as long as they stay constant a small
error isn't going to make much difference to the actual performance once
you true up the wheel radially.
You're not supposed to grind against the side of the wheel anyway.
I picked up the variable speed Delta 8" grinder awhile back and had
similar problems. Truing the wheels helped some, but ultimately what
cured all the vibration and shaking was to balance the wheels. I did
that with the Oneway Balancing System.
I purchased a grinder once that really had "out of true" wheels.
After considerable investigation, it turned out that despite the
grinder being seemingly well packaged, that it had been damaged in
shipment. Apparently, it had been dropped with the shaft of the
motor parallel to the ground and the weight of the two wheels at
the end of the shaft had been enough to bend them slightly.
If you can't get your grinder trued up, consider placing a dial
indicator against the shaft and slowly rotating it to check for
The shaft had significant runout. I took the slow-speed grinder back
to Woodcraft and got a full refund. Good thing I bought it at the
store, because they won't take back internet items purchased from
Woodcraft online and the thing is quite heavy to ship.
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