New bench grinder: cheap or just inexpensive?

[lslarry86]

I've been struggling with a weak old bench grinder that bogs down when I push too hard on it. This week I bought a new 8 inch Chinese grinder from Amazon:

https://www.amazon.com/gp/product/B003K2MOHW

The delivered unit looks close enough to the listing photo, but both wheels have chipped corners. The center holes are bigger than the arbors, so I had to center the wheels by trial and error. The bearings feel smooth when rotated by hand, and the grinder runs smoothly at top speed. But at mid speed it shakes in a scary way. That happens when spinning up and spinning down, and when I push hard with the work.

Is this thing dangerous, or should I just use it until things even out?
Is it common for the grind wheel holes to be oversized?

 

[Just for fun]

Well, without seeing the chipped wheels I can't really say.

Mine vibrates on the way up and down also and the shaft is not long enough for a 1" wide Norton wheels. Anyway I did fabricate new washers and replaced 1 wheel and that helped.

My original wheels if I remember right fit on the shaft correctly.

 

[jbaccell]

In my experience, most of the generic bench grinders come with wheels that are not very good and I usually replace them with quality wheels. The holes in the wheels should fit the shaft properly, although, I have had wheels come with plastic adapters that enable the wheel to be mounted on 1/2", 5/8", 3/4" and 1" shafts.

 

[C-Bag]

Is this thing dangerous, or should I just use it until things even out?

Yes, it could be dangerous with chipped wheels. Have pulled the wheels and done the ring test? If they don’t ring, they have cracks and could explode. You cannot fathom the damage they can do spinning at 3400rpm. Like shatter your skull dangerous. There are many threads here on H-M about this. Replacing the wheels with Norton’s did nothing on my 8” grinder, still shook like crazy. They were just as out of balance as the No names that came on it. Not until I put balancer wheels on it was I able to get it to run smooth.

 

[mmcmdl]

Don’t put up vibrating bench grinders

There are plenty of threads on this forum and on Youtube, that do a great job for ways to mitigate, reduce, increase noise and vibration. I recently purchased a quality 8” 3/4 hp Baldor grinder. There is no reason why a quality Weiler 8”x1” wire wheel, running on my bench grinder, should shake...

www.hobby-machinist.com

This may help you .

 

[rwdenney]

Mine shake as they spin up and down, and I need to find a way to balance them. I'm thinking a large, thick washer with an oversized hole under the clamp washer can be laterally offset to balance the wheel, but that's going to be a real challenge to find the balance position. I have already replaced my wheels and they are dressed and run true. Both of my grinders are cheapies--one a relatively new Delta and the other an import brand. Making a new guard and tool rest for the Delta is on the long-term list. It is a low-speed grinder with a speed adjustment that at least lets me find a speed that does not resonate. The import is a high-speed grinder and it's okay at speed, but shakes badly when coasting down. And there is no induction brake, so coasting down takes about five minutes.

There will probably be a Baldor in my future, but only when a unique buying opportunity appears here locally.

Rick "uses the grinder less after finally purchasing a 1x42 belt sander" Denney

 

[Just for fun]

Not until I put balancer wheels on it was I able to get it to run smooth.

What are balancer wheels?

 

[pontiac428]

Tame your vibes with an application of heavy dressing!

 

[lslarry86]

Well, without seeing the chipped wheels I can't really say.

Mine vibrates on the way up and down also and the shaft is not long enough for a 1" wide Norton wheels. Anyway I did fabricate new washers and replaced 1 wheel and that helped.

My original wheels if I remember right fit on the shaft correctly.

This is about the worst spot on the two wheels.

 

[lslarry86]

Yes, it could be dangerous with chipped wheels. Have pulled the wheels and done the ring test? If they don’t ring, they have cracks and could explode. You cannot fathom the damage they can do spinning at 3400rpm. Like shatter your skull dangerous. There are many threads here on H-M about this. Replacing the wheels with Norton’s did nothing on my 8” grinder, still shook like crazy. They were just as out of balance as the No names that came on it. Not until I put balancer wheels on it was I able to get it to run smooth.

Thanks for "ring test." Yes, my wheels ring.