Got bench grinder wobble? Here is my fix.

[Mike Leung]

I bought a Woodcraft slow speed grinder and when I turned it on it walked across my bench. The wheels wobbled so much and I had to do something before dressing the wheels. I found the wheels to be loose on the shafts because of the bushing ID bring too large. The flanges are a joke as well. They would fall into the recess near the shoulder and become non concentric to the shaft. What a Woodcraft put out. The shafts themselves are true so it was worth buying some bushings to fix this sucker. I ordered a couple of Forney bushings from Amazon for five bucks each. I also had a machined flange from my Unisaw Latin around. I needed to use the flange and also a 5" stabilizer on one side while the other side was fine with the original stamped flanges. I recorded a video of the fix in case it helps anyone with a similar problem.

http://youtu.be/pz06MEAtwYg
I know some people here would say just buy a baldor. I spent $75 for the grinder and $10 for bushings and the grinder runs really well now for just 10 minutes of my time.

[Anthony Diodati]

Good Job, nothing wrong with that.
Thanks,
Tony

[john davey]

Looks like you fixed it fine. I guess I got lucky as I have the same grinder and it is spinning perfectly.

[Mike Leung]

I was expecting it to run true as well. Some of my tools arrive ready to use with the included parts but not this one. Oh well. Can't win them all. At least the fix is a cheap and easy one.

[Jim Koepke]

Have you contacted Woodcraft?

They might want to know about their quality problem.

jtk

[Don Dorn]

Good advise - the bushings wouldn't be a problem, but lack the 5" blade stabilizers. Same grinder and mine works better out of the box than yours did, but not near as nice as your finished product.

[Derek Cohen]

Good advise - the bushings wouldn't be a problem, but lack the 5" blade stabilizers. Same grinder and mine works better out of the box than yours did, but not near as nice as your finished product.

Hi Don

It may be that all you need to do is balance the wheels. A fairly simple process that can make a huge difference to smoothness. Do you know how to do that?

Regards from Perth

Derek

[Don Dorn]

Hi Don

It may be that all you need to do is balance the wheels. A fairly simple process that can make a huge difference to smoothness. Do you know how to do that?

Regards from Perth

Derek

No, not without the "Oneway" kit.

[Derek Cohen]

Grinder wheels - just like the wheels on your car - need to be balanced to run smoothly.

The way to balance a wheel is to make a mark (draw a line from the centre to the perimeter) and then rotate the wheel slightly (loosen the nut, move the wheel, tighten again). Keep doing this until you get the least amount of vibration. Do both wheels.

Dressing the wheel should remove the last of the vibration.

I once had a 10" high speed grinder that was well out of balance. It sounded like a jet taking off. It vibrated so much that it would walk off a bench top even if held down with a clamp. It scared the bejesus out of me!

Regards from Perth

Derek

[Mike Tekin]

Have you contacted Woodcraft?

They might want to know about their quality problem.

jtk

Woodcraft was aware - I talked to them about it a while ago when I was looking for a grinder - they even included supplemental instructions on how to balance the Woodriver grinder

They did take action and since then stop making the grinders - They now sell a Rikon grinder in its place

Either way, Derek's instruction on balancing is simple and is all you need to do

[jamie shard]

The way to balance a wheel is to make a mark (draw a line from the centre to the perimeter) and then rotate the wheel slightly (loosen the nut, move the wheel, tighten again). Keep doing this until you get the least amount of vibration. Do both wheels.

Dressing the wheel should remove the last of the vibration.


Agreed! One way to do this is to move the wheel a 1/2 turn, then a 1/4 turn, then an 1/8 turn, etc. if the vibration persists. What is shocking is that one of these positions will stop 90% of the vibration. It's hard to believe that nothing else was done to the wheel besides simply rotating in on the shaft.

[phil harold]

While this looks is a great fix there is one safety problem
you need to protect the grinding wheels from the the flanges you added
just a piece of heavy card stock would work to protect the the grinding wheels from the steel cutting into the wheels and shattering them at the most in opportune time (you standing in front of them)
I always turn my grinder on then take a few steps away from it until it comes up to speed, ( I have seen one explode on a coworker as he started it )

other accidents that happen:
https://www.osha.gov/SLTC/machineguarding/grinder_accidents.html
more safety reminders
http://www.okhighered.org/ssherc/newsletters/osrhe/abrasive-wheel-grinder-safety.html

how to perform a ring test
http://www.nortonindustrial.com/uploadedFiles/SGindnortonabrasives/Documents/Safety%20-%20Ring%20Test%20a%20Grinding%20Wheels.pdf

more safety

http://www.ganoksin.com/borisat/nenam/grinding.htm


I bought a Woodcraft slow speed grinder and when I turned it on it walked across my bench. The wheels wobbled so much and I had to do something before dressing the wheels. I found the wheels to be loose on the shafts because of the bushing ID bring too large. The flanges are a joke as well. They would fall into the recess near the shoulder and become non concentric to the shaft. What a Woodcraft put out. The shafts themselves are true so it was worth buying some bushings to fix this sucker. I ordered a couple of Forney bushings from Amazon for five bucks each. I also had a machined flange from my Unisaw Latin around. I needed to use the flange and also a 5" stabilizer on one side while the other side was fine with the original stamped flanges. I recorded a video of the fix in case it helps anyone with a similar problem.

http://youtu.be/pz06MEAtwYg
I know some people here would say just buy a baldor. I spent $75 for the grinder and $10 for bushings and the grinder runs really well now for just 10 minutes of my time.

[Mike Leung]

Thanks for the tips Phil. I will add a cardstock shim as you suggested. The links you provided are great.


While this looks is a great fix there is one safety problem
you need to protect the grinding wheels from the the flanges you added
just a piece of heavy card stock would work to protect the the grinding wheels from the steel cutting into the wheels and shattering them at the most in opportune time (you standing in front of them)
I always turn my grinder on then take a few steps away from it until it comes up to speed, ( I have seen one explode on a coworker as he started it )

other accidents that happen:
https://www.osha.gov/SLTC/machineguarding/grinder_accidents.html
more safety reminders
http://www.okhighered.org/ssherc/newsletters/osrhe/abrasive-wheel-grinder-safety.html

how to perform a ring test
http://www.nortonindustrial.com/uploadedFiles/SGindnortonabrasives/Documents/Safety%20-%20Ring%20Test%20a%20Grinding%20Wheels.pdf

more safety

http://www.ganoksin.com/borisat/nenam/grinding.htm

[Mike Leung]

I did try and balance but it did not improve it much as the bushings were too loose so the wheels were not concentric. I did balance as you suggested after my upgrades to get my final results and it was an improvement.


Grinder wheels - just like the wheels on your car - need to be balanced to run smoothly.

The way to balance a wheel is to make a mark (draw a line from the centre to the perimeter) and then rotate the wheel slightly (loosen the nut, move the wheel, tighten again). Keep doing this until you get the least amount of vibration. Do both wheels.

Dressing the wheel should remove the last of the vibration.

I once had a 10" high speed grinder that was well out of balance. It sounded like a jet taking off. It vibrated so much that it would walk off a bench top even if held down with a clamp. It scared the bejesus out of me!

Regards from Perth

Derek

[Winton Applegate]

Well . . . I went looking for the other thread and found this 'un.
I was conferring with George Wilson.
From what he said and what I saw in the previous post photos I would strongly recommend RETURNING this grinder.
It isn't made right.
You need a real shoulder for the flange to seat against not the half fast machine work that is on this machine.
Seriously
Get another similar price machine but return this one.
Here is what George was saying incase you missed the Music Stand thread ( the music stands are great don't miss that one).

Winton,I think necking down the grind shaft is a bad idea on several counts. Especially if the flimsy flanges are so thin they fall into the neck!!

Why they are doing that? Most likely an easy way to avoid any corner with a radius. When they face off the register of the shaft,they let the tool go a bit farther into the shaft. But,there is not communication between whoever is responsible for making the tin can lid flanges. Else,they just don't care. The only solution for now is to buy thicker flanges.

If you can't buy thicker flanges,I'd suggest carefully cleaning the necked down place with acetone,and filling the groove with J.B. Weld. It is really great stuff,and adheres to steel ,CLEAN STEEL!! Really well. It is also very hard. And,it will stand 600º,which is fantastic. We use it to fill any little holes in our jewelry models,so they don't get caught in the rubber mold when it is made. The rubber mold is vulcanized at something like 450º. We needed something with real high heat resistance to use.

It the grinder over heats,the J.B. will be more than adequate. Make sure the J.B. is CAREFULLY filed flush with the shaft,or the flange will still not run true. I still suggest buying decent flanges anyway.

Necking down the shaft means that the shaft is no stronger than the diameter of the neck. All around,a very bad idea.

He is talking about the narrow place on the shaft, I am talking about the fine "thread" like area where a good stout shoulder should be. The two problems together are just too much.
If you don't unload this turkey now you may wish you had in the future.

[Winton Applegate]

PS: the shoulder should look like this
http://books.google.com/books?id=GSMZFIq_I2EC&pg=PA379&lpg=PA379&dq=grind+stone+shaft+shoulder+seat&source=bl&ots=oUXr5jfJTp&sig=n0z5vt8Sh0BEWkoG0bDWeh6wp-s&hl=en&sa=X&ei=SZqaUrmOGMXzoATZ94KwBA&ved=0CD8Q6AEwBA#v=onepage&q=grind%20stone%20shaft%20shoulder%20seat&f=false

[Tom Blank]

Here are two more fixes for bushings and flanges. Can't help with a miscut shoulder. I just got a Rikon and the wheels were the standard out of balance, replaced one with a Norton with it's three plastic bushings and it was equally as bad. Messing around with rotating inside flange, wheel, and outside flange I could get it pretty close, but it still vibrated.

The real fix was similar to Mike's. In place of the saw spacer he used (which I did not have), I found that 9/16" grade 8 flat washers just fit on the shaft and butt up to the shoulder. They are reasonably thick, but It took two to provide clearance. The hardware store I frequent had Forney bushings, but only a smaller set. They did carry bronze bushings, but they did not have a 5/8" to 1". It took two, a 5/8" to 3/4" and a 3/4" to 1" to make it work. Those two nest tight together and are a slip fit on the shaft and in the wheel.

When I installed the grade 8 washers and bronze bushing it made a noticeable improvement. I have a bit invested in the bronze bushings but not much more than the Forneys and saw blade spacers and they should outlast the grinder.

Just another way to do it.

Tom

[Tom M King]

No wobble here.

[Bob Jones]

I have the oneway wheel balancer and it makes my high speed 8 inch Dayton absolutely vibration free. It's not cheap, but it works really well.