Tool Balancing A 8" Grinding Wheel

[terry_g]

About a decade ago I purchased a Mastercraft 8" grinder from Canadian Tire. It was on sale for a fraction of its normal price $16
and change before taxes. The regular price was around $80 If I remember correctly. It has served me well over the years I replaced
the coarse carborundum wheel with a green wheel which I seldom used. I ordered a Norton premium 8" white wheel from Amazon
to replace the green one. When I finally got around to installing it I was shocked at how out of balance it was. I would have returned
it but the 90 day return period had passed. So Could I balance it or is it garbage?
I made an arbor to fit the wheel and made a point to balance the wheel on and set up in the vice. You can see how far off it is.




Next I cut a slice off a piece of 2.5" mystery metal shaft I had in the metal pile and turned it. Then I set it on top of the wheel and
moved it to where the wheel was level then marked its location on the paper label on the wheel.


Next I carefully marked the new washer with where the bore in the wheel was located. Then chucked it in the small 4 jaw and bored
it for the shaft.

 

[terry_g]

I had to cut a recess in it for the nut big enough for a socket to fit. The original washers were pretty wimpy.


I made an inner washer as well and an aluminum sleeve the originals required a few tries tightening the nut to get the wheel to
run true.


It took a couple tries to get it right I loosened and rotated the balance weight a little bit each time until the vibration was the least.
Its way better now.

 

[Former Member]

I'm surprised that Nortons wheel was that far out, but it happens.

One important question, did you check your grinder shaft for being true, what can happen over time is the shaft adjusts to the wheel and results in a balanced system, new wheel and well no more balance.

 

[terry_g]

Yes the shaft is true and the bearings are tight. I trued the wheel with a diamond dressing tool.

 

[trlvn]

Just to be sure about your balancing system, did you try putting the old grey or green wheels on to check their balance?

Craig

 

[terry_g]

Previously I swapped the coarse grey wheel with the green a couple times.
I am impressed how well balanced the cheap wheels are that came with the grinder.
The green wheel was very well balanced as well.

 

[VicHobbyGuy]

@terry_g Very interesting; thanks. What's your conclusion about the reason for the vibration with the Norton wheel - variation in thickness or density, or hole not square to the face or concentric with the rim, ? If the last, wouldn't dressing the wheel to round solve the problem? Did you measure the radius? I have a couple of those white Norton wheels and there's a bit of vibration with mine as well - less now that they have been dressed and used a bit. Off-topic. They are pretty soft but grind HSS really well. Hardness vs efficiency/sharpness is the usual tradeoff; I understand that.

 

[jcdammeyer]

Fascinating. I've put up with the slight vibration on mine. Your balancing solution looks like it would be easy enough to try.
Thanks for posting that.

 

[terry_g]

The wheel runs true and I dressed it so it must be variations in density causing the vibration.
My grinder bench has a 6" and an 8" grinder. After I first installed the white 8" wheel I had to screw
both grinders to the bench.