Procedure to true a grinder wheel?

[Phisherman]

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.

[Greg G]

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 be dangerous.

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.

Greg G.

[Greg G]

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.

Greg G.

[dpb]

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., ...

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[Chris Friesen]

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.

Chris

[Michael Faurot]

[...]

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[1].

[1]:

[Nonny]

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 runout.

[Phisherman]

Thanks. Great suggestion and I do have a dial indicator to test for runout.

[Phisherman]

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.