# Truing bench grinder wheels



## mu38&Bg# (May 10, 2010)

I've been using a bench grinder for a while now. During run up it shakes quite a bit, enough that the rests touch the wheels. They have not worn round it seems. Truing the wheel while it's running doesn't help because it doesn't spin true. This grinder has two wheels and I bet both are out of true and balance. Would I remove one to true the other? Most of the stuff I found online says to true the wheel to bring it back into balance. That should work if the grinder axis was rigid enough not to move due to the out of balance. Seems like it might be time to make proper rests for it it also.


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## kd7fhg (May 10, 2010)

Not seeing the grinder can not really tell what the problem is, but I would bet that the hole in the wheel is larger than the shaft, the shaft could be bent or the bearings are worn out. I would install a new grinding wheel or make a disk on the lathe, that you can mount on the shaft and check with a dial indicator. As a final note I would not use this grinder until this is resolved as the wheel could come apart as out of balance as they are.

Rex


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## jmshep (May 10, 2010)

May I recommend the following publication that is available as a free download:
http://books.hse.gov.uk/hse/public/saleproduct.jsf?catalogueCode=9780717617395
It offers advice on the use of grinding machines and includes the correct method of mounting wheels.

John S


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## mu38&Bg# (May 11, 2010)

I have that book, but it doesn't give any specific methods. It's a bench grinder Sears Craftsman China special. It's not a problem with the bearings or shaft. The wheels have not worn round. As such they are now out of balance. If I had a rigid rest and was able to mount a diamond like a tool post on a lathe I'm sure this would take care of things. The grinder has a typical sheet metal wheel guard and the rest is attached to that with no way of mounting a tool. Is my logic correct in that the rotary truing tool will not correct the problem I have because of the out of balance condition? As a last resort is mounting the wheel on my lathe an option. I hate to do this. By turning the wheel I can see there is about 1/16" TIR on the wheel I typically use. From what I gather in the book this is appears to be due to not truing the wheel often enough.


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## kd7fhg (May 11, 2010)

I would replace the wheels with a quality ones, I have never had to "true" the wheels or "balance" a grinding wheel when new, dress them yes to level the grooves, but only after being used. 

Rex


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## mu38&Bg# (May 11, 2010)

OK, probably they were junk to begin with.


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## jmshep (May 11, 2010)

Whatever you do do not mount the wheels on your lathe!
Not only is this very dangerous to you but it may also damage your lathe - the abrasive will get everywhere!

From what you have said you are resigned to getting new wheels and I am sure that is the way to go.


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## rake60 (May 11, 2010)

First thing I would do is remove the wheels and put a dial indicator on the arbors.
Check them for any free play or axial run out.

A bad bearing/bushing or bend arbor shaft will make a bench grinder *DANGEROUS.*

Rick


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## mu38&Bg# (May 11, 2010)

I'll check the grinder before mounting new wheels. Now to see if i can buy a pair of decent wheels for less than I paid for the grinder.


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