Grinder Wheels

H

Hukshawn

Forum Guest
Register Today
I got an 8" bench grinder for Christmas. Not of terribly great quality, but I asked for this one, so whatever. I have a 6" with a stone and a wire wheel. I wanted something bigger for grinding tool bits. This one works nice. The wheels are heavy so takes a while to get up to speed, but maaaan are they out of round. Thing walks across the bench and makes a hell of a noise that vibrates the house.
I have a flat diamond dresser that I use on the 6" and got that wheel pretty true, but I worked on these 8" for quite a while. Garage is cloudy from stone dust. I have the face pretty true but the sides travel back and forth almost a 1/16". I can't seems to true them up. I have the dresser pushed against the rest to try to keep it steady as I grind. Just not happening.
Ideas?

I've almost considered rigging them up in the lathe, but that might warrant a tear down and clean once I'm done to get rid of all the damaging dust...
 
I assume you're using the usual plastic grinding wheel bushings/adapters? Those things are TERRIBLE. If you have a lathe you should make some simple aluminum ones that act as bushings and washers in one. The OD of the bushing section should be a bit smaller than the ID of the grinding wheel so that the aluminum can't expand when hot and crack the wheel. That was my first ever lathe project and it has served me very well.



cc491e31ec5388a3994e857c5807c4a1.jpg
 
Ya I think I may have to take it all apart this weekend and see what's up. They're way too wobbly to be just the wheels... even cheap Chinese wheels, I assume they are still trued SOME how...? Or are they just molded and shipped?
 
Don't mess with the wheels until you find out the bearing condition and fit, and the runout of the spindle itself. Sometimes the plates on the sides of the wheels are also poorly machined and cause issues. Make sure you have good blotters on the wheels, and I agree with Jon about the plastic bushings, even worse when there is more than one stacked one inside the other. Start with no wheels or anything, just bare spindle, and see how it runs. If that is not good, sell it and start over. If that is smooth, put a wheel on one side, making sure everything fits correctly without slop or runout, then run it with just the one wheel.
 
Hmmm, okay. I did notice the washers had a wobble to them, but hard to see around the shrouds. Sounds like washer lathing may be in my future. (If the shafts are out then it's just going back to the store, it was bought new)
 
A grinder just has to spin the wheels, and do so smoothly. While there is a difference between the budget ones and the better ones, for most people the budget ones are sufficient if you get a good sample.

Some have better tool rests than others, but I'm pretty sure even the good ones still suck (only the reversible, double-sided tool grinders have particularly useful tool rests). If it spins smoothly without the wheel, and it seems like the bearings aren't crap, then you can probably make it work. But keep in mind that it's possible for the shaft to be bent and still spin relatively smoothly without a wheel mounted, but never with one mounted. I returned three wire wheels before realizing that mine had been damaged on one side. No vibration problems at all with a wheel only on the other side. That's the troubleshooting process Bob mentioned.
 
You should be able to visually see runout at the shaft ends with the wheels removed if any is present. If you find runout, check for a loose bearing to shaft fit as well as for a bent shaft. Import machine, no doubt, and you are the QC inspector...
 
Last edited:
In my case the run out was too slight to see directly, and I wasn't able to get a good indicator reading on the shaft with more than a decade of scratches. That also makes it hard to identify the bend to try to straighten it, but as a now almost 15 year old Harbor Freight grinder that only cost me $30 or so at the time, I'm not going to bother fixing it.

The irony is that the week before I discovered that it was damaged I gave my brother a nice Buffalo grinder that my wife's grandfather passed on to us. I didn't see the need for two 6" bench grinders, so I gave him the better one. It has to be at least 20 years old and still takes a good 3 or 4 minutes to spin down.
 
I'll take the wheels off and have a look. Il set up the dial test indicator if need be.

Thanks guys. I never thought of the shaft and bushings.
 
Just went through this with the Chinese one I bought for my planer blade grinder. The stamped washers were no where near flat, made a heavy one to register on the shoulder of the shaft and used the original on the outside. Took the side wobble out of the wheel.
You might want to consider buying better wheels, any of the ones I've seen come with these grinders are little more than round rocks.

Greg
 
Back
Top