Bench Grinding Wheels

J

jschmidling

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I bought a low end 6" bench grinder and can't believe the poor quality of the wheels that came with it. They not only were impossible to get even one in balance but they actually rode directly on the motor shaft. No bushing or collar, just AO on steel.

I then purchased what I thought was a quality product from a known brand (Norton) and it has worse problems than the Chinese junk.

It has a one inch bore with the usual adapters so that's no problem.

When I mount it on the grinder and turn it by hand, it is round and true. Hardly needing any dressing at all.

All hell breaks loose when I try to run the grinder.

When it comes to a stop, it swings like a pendulum to the same position, no matter how I mount or rotate it or where I position it by hand. It acts like a large sector is made from styrafoam. It is totally useless.

Where does one get decent grinding wheels these day.

Jack
 
I have not had issues with Norton wheels themselves, but sometimes the supplied plastic bushings suck. I have had them too loose in the wheel, too loose on the shaft, and both at the same time. have also had them fit snug but not concentric. Made new bushings and wheels ran smooth.
 
Have you checked the run-out on the shaft to make sure that's not the problem?
 
I just went through this similar cycle (https://www.hobby-machinist.com/threads/grinder-problem.78944/#post-675631), with a Dewalt 756 and Norton wheels. Ended up buying the Raptor aluminum hubs and nuts (https://www.woodturnerscatalog.com/p/97/6196/raptor-R3X-Grinding-Wheel-Bushing-2-Piece-Set) and trashing what came with the grinder and wheels (which were NOT the wheels that came with the grinder), and setting up the grinder outside and dressing it until the vibration disappeared. Took awhile. Definitely need a mask and goggles though because it looked like a cyclone blowing through with all the dust.
Tim
 
Is the grinder in balance itself? I was given a HF grinder, a real POS; everything wiggled and wobbled, I made new inside and outside washers, changed to USA wheels, dressed the wheels true, and it still vibrates partially due to the motor being out of balance; that combined with work rests and the wheel guards that are made out of material not much stronger than a tin can, have me nearly ready to junk the damned thing.
 
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Sounds like the same grinder i purchased from HF. If I counted my time patching up the piece of junk it would have been better to spend more on a better grinder. Probably put 6 hours into just making it run with out walking all over the shop.
 
gwade said:
Have you checked the run-out on the shaft to make sure that's not the problem?
Click to expand...

There is no problem with the motor. It just hums away with no vibration at all and there is no detectable runout on either end.

I made a bushing for the Norton wheel that is a near press fit on shaft and bore. I insert a 1/2" rod and set it on two tracks and it swings down to that mysterious place that does not correspond with the eccentricity of the wheel which is very slight.

This brings up a question I have on dressing a wheel.

In my past experience with pre-Chinese grinders, a wheel was dressed when the surface was no longer flat and clean, not to make an eccentric wheel round. I could buy a new wheel, put it on the grinder and use it without shaking the foundation.

On a surface grinder, we ran a diamond back and forth to true it up but that was a different ball game from hand grinding tool bits.

All I ever owned or needed was a handheld dresser with those little carbide wheels to keep my grinders in order.

Now the junk wheels out there need to be made round and it does not seem one could do this with a hand held dresser because it would just follow the shape of the wheel and never correct the eccentricity.

What is the proper tool/method of correcting a wheel on a bench grinder?

Jack
 
I have an old Craftsman 6" grinder that runs so smooth that its hard to tell that its running. I know that if I take the Norton wheels off, I will never get them back to the location they are in now so I don't move them. I remember when I installed them years ago that I had to dress them smooth but I don't remember them being so out of round that they were all that imbalanced. In any case, I use a T-type diamond dresser and it gets them nice, flat and round. Seems to work fine and that thing cuts fast! If you use one, be sure to work outside and wear eye protection and a good mask or respirator.

I recently decided to buy some compressed paper wheels (looks suspiciously like MDF to me) to sharpen knives with. I'll report on it when I have time. In any case, rather than disturb the wheels on my Craftsman grinder, I bought a new Jet 1/2HP bench grinder to use those wheels on and that thing is as smooth as silk without the wheels. I installed the paper wheels and they fit tight on the shaft and ran with only a slight vibration. I clocked one wheel at a time, loosening the retaining nut and rotating the wheel 1/4 turn at a time until it ran smooth. Then I installed the other wheel and did the same thing. Now it runs as smooth as I could want.

My suggestion is to buy that T-shaped dresser and work on one wheel at a time until you get it running smooth and balanced, then do the same for the other one.
 
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