Bench Grinder run-out

MikeWi

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How bad did I mess up here? I bought a Harbor freight 8" grinder, after Christmas ,and didn't open it until today since I just got my white wheel and a stand for it. Turns out there's a significant amount of sideways wobble in the wheels, and of course, the receipt is no where to be found. The shaft has about .0015 of runout ,but the shoulder for the inboard washer is too low to get a reliable reading, and I suspect that's where the trouble is as the washers appear to be flat.

Any thoughts on how to rescue it? I always keep receipts too...
 
Not to worry--you did good. Those grinder's washers, shaft, and wheels are terrible, but salvageable for a lot less than a Baldor 8".

I combined a cheapo 8" grinder with the Oneway balancing kit and one good Norton grinding wheel (46 grit I think) and have a very nice set up (I still use the fine white wheel that came with the cheapo grinder--it runs ok after balancing). The Oneway kit comes with high-quality washers and a balancing set up.
https://oneway.ca/products-category/sharpening-grinding-jigs/Balancing Systems

If you don't want to drop the coin on the Oneway system, you may be able to significantly improve things by fiddling with the washers, both rotational location and sides of the wheel. You might even be able to true them up if you have a lathe (or make new ones).
 
The only way to rescue it the correct way would be to take out the shaft and re cut the shaft faces between centers.
 
The only way to rescue it the correct way would be to take out the shaft and re cut the shaft faces between centers.
That's what I was thinking too, but the shoulder that the washer sits against is about the thickness of my fingernail. I'm going to try making a new shoulder with a piece of steel bored to a slip-fit over the shaft. I have the room for it, and it would give me a truer shoulder to go up against. I'll probably just make new washers too, as these stamped ones don't look very promising.

edit: DOH! I forgot I don't have a boring bar that small! If it ain't one thing...
 
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If your grinder is like my Rikon grinder the issue is partly the shaft having too small a shoulder, the washer having too large a hole and the bushing on the wheel being too large.

The really shallow shoulder on my Rikon.

Grinder_shaft_shallow_registration_shoulder_6348_edited.jpg

I made custom washers which have a better fit, but still have wobble in the wheels. I found a piece of masking tape over the shaft helps with the bushing being too large.

Grinder_wheel_installed_cut_off_excess_tape_6351_small.jpg
 
I just bought Harold Hall's book "Tool & Cutter Sharpening". In it, he describes clamping the whole grinder to the lathe bed and indicating the spindle parallel to the ways. You can then true up the spindle with the grinder under its own power.
 
Have at it, but I'm tellin' you, the Oneway stuff is quick, easy, and not all that expensive. And it works.
 
I had similar issues with a lower end Delta grinder. The shaft was straight but crappy washers and narrow shaft made for wobbly wheels. I replaced the inner washers with a combination arbor/washer machined out of one piece of aluminum, with sliding fit on the shaft, and it now takes 1" ID wheels which are typically professional. Works much better.
 
I had similar issues with a lower end Delta grinder. The shaft was straight but crappy washers and narrow shaft made for wobbly wheels. I replaced the inner washers with a combination arbor/washer machined out of one piece of aluminum, with sliding fit on the shaft, and it now takes 1" ID wheels which are typically professional. Works much better.
I did the same thing on a 6" grinder. I didn't make shaft bushings though. Really improved the wobble of the grinder. The stamped washers are junk.
 
You can buy a cheap HF grinder and play around with it and spend more money and time getting it work decently (maybe). Or you can buy a Baldor or similar and be done with it, probably for your life time. My 3 cents…Dave
 
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