Balancing Bench Grinder Wheels

I have the usual cheapo DIY 6" bench grinder, and obviously it is a nasty thing which shakes the whole bench when in use as the wheels have never been dressed or balanced as I don't have the kit and its too much bother.

The Americans have things that they put on the wheels of their trucks (Centramatic is one brand) which have weights in a tube and claim to dynamically balance a wheel on the vehicle even for things like trailers which tend to sit idle long enough that their tyres go out of round.

So last night I took an old trailer wheen bearing outer race that I happend to have around (approx 2" dia), put half a dozen small ball bearings in it and clamped it to the side of the grinding wheel by reversing the dished washer.

It didn't cure the vibration instantly but it did seem to lessen it a bit. Was this my imagination? Do these things even work? Should I persist with experimentation? Any idea how big a bearing and how much weight would be needed?

Edited By Adrian R2 on 10/07/2023 09:06:22

I balance wheels for the surface and cylindrical grinders; both have hubs with adjustable weights. But I've never bothered with bench grinder wheels. I don't have a problem with vibration. Rather than spend money on a sticking plaster it would be better to invest in a quality wheel and/or bench grinder. Dressing a wheel won't do much to address balance unless the wheel is running wildly out of true.

Andrew

PLEASE BE VERY CAREFUL ! What your doing is potentially very dangerous ! Fitting the dished washer back to front stresses the wheel. Cheap and not so cheap bench grinders seldom have any way of balancing the wheels though dressing them may help to keep things in balance. A poorly balanced wheel can make the grinder difficult to used and throw the wheel even further out. Your question on weights could only be addressed as with road wheels by putting the wheel on a proper balancer. As to further experimemtation I would say NO. Noel.

@Andrew, I haven't spent any money so far but yes it would be nice to have better kit but that probably means a big chunk of 3 phase iron and an inverter to run it. All the reviews I found of replacement wheels had someone complaining theirs was out of balance from new.

@Noel, indeed. The bearing I chose has a contact area on the wheel which is very close to that of the dished washer so stresses are I think OK, if it needs a bigger bearing then a spacer could be made to suit. That said I did turn it on using an extension lead from across the room rather than standing right next to it.

Plenty more of these.

Bench grinder modification

This chap seems to have got something to work:

http://www.nwnative.us/Grant/shop%20articles/sharpTable/balancing/

Hi Adrian R2, bench grinding wheels are balance with chalk by the manufacturers, but they have specialist equipment and a good understand of where and how and weight of, to introduce the chalk into the porous wheels. As Andrew Johnston has said, the better quality grinders have provisions incorporated into the design of the grinder for the use of balancing weights. You should not attempt to modify the design of a bench grinder, and as Noel has pointed out, never put the dished washers on the wrong way round, as there must be an equal area of contact and pressure on each side of the wheel. If the vibration can't be solved by dressing or replacing the wheels, then scrap it, as it is quite likely to bite you back at some time or other. Never get complacent with grinders.

Regards Nick.

My £25 B&Q 6" bench grinder is fine with no vibration even when I remounted the stones.

You need to buy your budget grinder from somewhere local so you can take it back when it behaves like your does.

It simple to check wheel wobble with a pencil and an out of balance (weight) wheel will always stop at the same point.

Now I'm not one to stop innovation, but I wouldn't want to fudge a grinder with bent axles or a stone that runs true, but still produces a wobble, the wheels are not reinforced like angle grinder ones so continuing to run one might eventually break even an otherwise good wheel. Not forgetting that by then you will be stood in front of it.

This is the 250W Wickes version but I've had it too long to go back and complain now. It runs OK with no stones and acceptably with only the coarse one mounted but the fine one starts the bench rattling, hence wondering about a retrofit solution. To save any further excitement I will order another wheel and see if it's any better.

Clough42 did a couple of wheel balancing videos for his new surface grinder, worth a look. I’ve never bothered with trying to balance a wheel for a bench grinder and I can’t remember seeing one done at work any time. Balance is done on finishing grinders to get a smooth finish, surface grinder etc. Out of balance can show in the surface finish as ripples, hardly a problem with an off hand grinder. The main thing is that the wheel is not so out of balance that it can explode at full speed. Perhaps fastening the grinder down to a heavy bench would help to damp the vibration.

My bench grinder was terrible from new. El Cheepo. I removed the plastic bushes from the centres & remade them from Delrin on the lathe. Never had a minutes bother since.

Steve.

Assuming you have two wheels fitted to your bench grinder slacken one wheel and rotate it about 30 degrees and retighten if no improvement rotate another 30 degrees and so on. It is possible you have two heavy sides together.

This all sounds like a recipe for disaster, try and find someone local to you that works in an engineering shop they may know of a contact to help you before you do yourself an injury that you could regret for the rest off your life!!

Thanks for the concern but you are worrying too much, I shall proceed with the utmost caution.

Both my bench grinders, made by KEF and Wolf, are single phase and there is no provision for balancing the wheels. I normally buy grinding wheels from Abtec4abrasives.

Andrew

Out of balance wheels are more often out of true wheels. The biggest culprit is the cheapo pressed side plates that clamp them, coupled with over-tightning.

Turn a pair of thicker plates for clamping the wheels and they will run more true.

Experimenting with grinding wheels when you don’t understand what you’re doing can have fatal consequences, there have been fatal injuries when a wheel rotating at speed lets go, is your life not worth the extra expense of a quality, safe , piece of equipment. Dave W

The grinding wheels on these cheaper bench grinders do not usually have a very close fit on the arbor. You can possibly improve a bit on the vibration by shifting the stone on its arbor and trying to find a sweet spot. Niko.

Edited By speelwerk on 10/07/2023 20:34:45

I have a vague recollection of someone describing how he made Balance disc which I think were fitted behind the grinding wheel. Could have been Harold Hall? or maybe in the SMEE Journal?

I believe that the HSE state that only properly trained staff should be allowed to change wheels in a factory. All that can be done about 'men in sheds', is to provide reliable good advice via this forum and the magazines then it's up to the grinder user to take heed for his/her safety.