Grinding wheel wobble

[Dan Forman]

I just received a Norton 3X60-1 grinding wheel for my Jet 8" bench grinder. The grinder came with two general purpose grey aluminum oxide wheels, but I wanted to upgrade to the cooler grinding wheel. The problem is that the new wheel wobbles and makes the whole rig bounce around a bit, whereas the original wheels run smooth as silk with no vibration whatever. The motion is not only front to back, but side to side as well.

The originals are bored to 5/8 inch, the Norton to 1' with a series of concentric bushings. These may be part of the problem, as the the wheel doesn't seat as solidly with them as the originals. There was no play in the originals before tightening the arbor nut, whereas there is a slight amount with the new wheel.

Is this a matter of being out of balance? I see that Lee Valley has a wheel balancing kit, but it's not exactly cheap, about $50 to do 2 wheels.

Could the bushings be at fault? I don't know how the wheel could run smoothly if not fitted properly to the arbor, but then again I don't see Norton selling wheels that wouldn't work on most grinders either.

The wheel was supposed to come with a diamond dresser, but it didn't make it into the box. Even so, that wouldn't fix the side to side wobble, and wouldn't help if the bushings are at fault.

Does anyone have any ideas on this?

Dan

[Jim Becker]

Unfortunately, many wheels "wobble" a bit due to density differences. But also check that when you slip it on the shaft that the bushings remain centered in the bore.

BTW, the OneWay wheel balancing system really does work...it's on my list for aquisition as soon as I change wheels sometime this year because I've always had the same problem as you are experiencing with both of my grinders. And it doesn't matter how much I dress them, even with the excellent OneWay dresser for the Wolverine system.

[John Shuk]

To repeat what Jim said. Oneway's system does work. You have to experience it to believe it. Oneway is making pretty good stuff.

[Dale Thompson]

Dan,
Norton usually makes a pretty good wheel. However the 1" to 5/8" reduction is very significant. Didn't your supplier have anything closer to the 5/8"? I question whether ANYTHING will give you good results with that kind of a "Rube Goldberg" reduction. :( I would return the wheel for something more compatible with your grinder.

With that said, do you have a way of measuring TIR on both the side-to-side wobble and the front-to-back concentricity? With these measurements, you may be able to "adjust" the bushings to give you a more satisfactory result.

By the way, be REALLY careful of an out-of-round grinding wheel! Even with a quality manufacturer like Norton, the adhesives holding the grit together are not intended to compensate for severe "wobble"! An exploding wheel will seriously impact your chances of appearing on the cover of Playgirl Magazine. :( Enough said! :)

Dale T.

[Steve Stube]

The wheel alignment and transfer of power is accomplished thru the blotters and large supporting metal washers on each side of the wheel. Sometimes the hole is not perpendicular to the side of the wheels or parallel to the face of the grinding face. On the older grinding wheels with poured lead centers you simply scraped the offending surface and tightened the wheel with blotters in place. The paper blotter material is important to distributing the load on the wheel but the bushing must be loose enough to allow for alignment. Perhaps your hole is a-skew and the bushings too tight.

[Dan Forman]

Thanks for the input guys. I have been playing around with it a bit more, tightened up the bushings with shims of tape placed between them, but it makes no difference. Having had the wheel on and off several times, the amount of wobble does vary, presumably due to the way it went on each time. It is not terribly dramatic, but certainly is noticable. I guess I will try the balancing kit, as that seems like the most likely solution. Looks like a one piece bushing is part of the kit, so that might help too. I will report back on how it works.

Dan

[Rob Matarazzo]

Sorry for dredging up this 8 year old thread, but I found this while researching this issue. I have the exact same problem. In my case when I put a Norton wheel on my 6" Delta bench grinder, I ended up with a bad case of the wobbles just as you describe. Did you ever get this sorted out?

[Reg Lilly]

If you're still around, try the Raptor RX3 grinding wheel bushing. 18 bucks.

[Robert Engel]

Had the same issue. With me, those plastic concentric bushings were the problem-too much slack.

I've seen guys make their own by turning a wooden insert and boring the arbor hole in the exact middle.

I did the same thing with the paper shims and eventually got the wobble out.

[Ronald Blue]

Not really wanting to add on to an old thread but here goes anyway. There isn't a grinding wheel on the market that is going to run perfectly true out of the box. That's guaranteed. That's why you need a wheel dresser. A wheel dresser not only trues the circumference of the wheel but if using it creates a groove or other wear pattern or a glazed condition touch it up with the dresser. Always adjust the tool rest up close to the wheel. WEAR safety glasses, goggles, or a face shield. As for side to side wobble that is a given as well. If it changes when you mount and demount then you either have an issue with your washers and arbor or the wheel is sloppy on the bushings and not mounting up as true as it should. All wheels will have side to side run out. It is important to have the paper blotters on as an insulation between metal backing washers and the actual wheel. They reduce the chances of wheel breakage. An out of balance wheel isn't at any higher risk of exploding than a balanced wheel. You should "ring" test any wheel before mounting it even if it's brand new. Always make sure the guards are in place and stand to the side when you first turn the grinder on. I have saw what a exploding wheel can do in person and you don't want to be in the "line of fire". Grinders are as safe as any other tool if you follow safe practices.

[Tom M King]

325974I gave up on friable wheels. This was out of the box.

[John K Jordan]

Metabo is a fantastic grinder. I have 5 grinders and the Metabo is my favorite. Added two CBN wheels recently to my tool sharpening station and now I'm a believer.