Bench Grinder Bush

The bush/clamping plate on my bench grinder broke when trying to remove one of the wheels as pet the attached pics.
I'm thinking of machining a new one can someone advise me as to the following;

1. Can the part be made out of aluminiun or brass

2. Do I need to replace the part on the other side in order to balance the grinder

3. How tight should the nuts be holding the wheels on the grinder shaft.

Your advise would be appreciated.

Russell Allsop

I have seen many Far Eastern six and eight inch bench grinders with pressed steel flanges so I personally wouldn’t worry about using ally or brass but no doubt the purists will say they should be steel of a certain grade, I cannot see any reason to replace the one on the other side, as for tightening the wheel, it must have blotters either side and just nipped up enough to stop it slipping. Please note that this is just my opinion not a recommendation and it’s up to you to decide if it’s safe.

Aluminium is suitable for one of these. Many are made of aluminium from new.

David

Like Baz, just use steel, no you don't need to replace both, and the blotters, as the name implies blotting paper or something like it will work. Having had great trouble with badly balanced wheels it might be worth trying to balance the wheels, though this would need a different type of side plate and a simple balancing way ! Most if not all grinders have left and right hand threads that should keep the wheel tight. When you have it all together, stand to one side as you turn it on and leave it running for 10mins, does it vibrate badly if yes then it is out of balance Please be careful ! Noel.

Cornflakes packets are ideal for blotters if you need to make any and do as Noel says, stand out of the line of fire when you turn it on. If it is badly out of balance you can loosen one wheel and rotate it say 90 degrees, re tighten and try again, keep rotating the one wheel at 90 degree intervals and trying it, hopefully you will end up with the heavy sides of the wheels opposite each other which should reduce vibration. In the good old days abrasive wheels were made to much better standards than they seem to be now.

Hi Russell, whatever metal you use, it must be the same diameter as the one on the other side, I don't mean to the last micron, but you should be able to get it to less than 0.5mm difference.

Regards Nick.

It's important to make the new flange with gripping diameters the same as the old one, to avoid stressing the wheel when tightening the nut. I've found turning the wheel small angles 0n the shaft before final tightening to be a method for reducing sideways wobble of the wheel rim.

As Noel says stand to one side when turning on this is the time a lot of wheels break up and as for tightness hand tight plus less than half a flat the opposite nature of the threads does the rest

Further to what Clive Brown says about gripping diameters the proper gripping rim width is pretty narrow.

Maybe 1/4" or so.

Some of the economy range grinders have very poorly designed flanges with drastically excessive gripping flange widths. The simple pressed ones can be horribly bad in that respect. Often seriously less than flat too.

I have a bar of dreadful, almost too soft to turn, aluminium that is steadily being used up for wheel flanges and the like. I figure a nice soft surface on the gripping bit is a good thing. Besides I have to do something with the stuff even if it owes me nothing having been given to me by a pal notorious for not letting anything go for free. Wonder why it escaped!

Clive

The bush is 70mm diameter and appears to be a plated casting, based on the advise received I will make a identical bush out of aluminium (easier to machine on my mini lathe) and proceed with caution for the first run, many thanks for the advise.

The HSE guide Safety in the use of abrasive wheels is worth reading even if it does not necessarily bind amateur users:

https://www.hse.gov.uk/pubns/books/hsg17.htm

Steel is the optimum material and stainless will avoid the absorbent "blotters" promoting rust on the flanges.

Hi, I do have a summery of wheel mount procedures in an album Wheel Mounting which should be followed by everyone regardless of home or work use.

Regards Nick.