Bench Grinding Wheels

[Janderso]

I bought a heavy 3/4 hp 8” bench grinder from Grainger. One side has the extended shaft for a buffing wheel, no guard, the other standard shrouded grinder with pedestal.
The wheel that came with it went in the garbage. I bought a Norton wheel, trued it up and now runs very smooth.
I haven’t been too impressed with Norton lately.
It seems they have the market cornered at MSC, Travers, Grainger etc.
Rodiac wheels are hard to find. In my experience

 

[Tozguy]

I made a bushing for the Norton wheel that is a near press fit on shaft and bore. I insert a 1/2" rod and set it on two tracks and it swings down to that mysterious place that does not correspond with the eccentricity of the wheel which is very slight.

There is only so much that can be done with cheap wheels. However on all wheels the center hole is not meant to be concentric and the wheel should not be a tight fit on the shaft. The proper way to mount a wheel is shown here:


This allows the wheel to be offset somewhat on the shaft to get the least runout on the circumference of the wheel.
With that set then dress the outside to remove any residual runout. After this If there is still an unacceptable imbalance in the set up then I would scrap the wheel.

 

[Tozguy]

All I ever owned or needed was a handheld dresser with those little carbide wheels to keep my grinders in order.

I never had much luck with those dressers either. The T shaped diamond dresser that Mikey mentions is what works best for me too.

 

[royesses]

This is what I use:


I set the diamond to cut about a thousandth or two at a pass. gets the wheel true and leaves a very nice surface. There are commercial versions that are pricey. Amazon sells them. This is one that I made. This photo is before I added and milled a UHMW plastic plate to the bottom to slide easily on the tool rest.

Roy

 

[jschmidling]

There is only so much that can be done with cheap wheels. However on all wheels the center hole is not meant to be concentric and the wheel should not be a tight fit on the shaft.

This is not only counter-intuitive but seems to contradict basic geometry.

By definition, the edge of a dressed wheel is both coaxial and concentric with the hole in the center.

If it is not concentric, we must remove material from the edge to make it so.

Why not start out with the hole in the middle?

If the hole is in the middle, why would you want a sloppy fit which forces us to futz around to get it in the middle?

With a snug fit, a properly dressed wheel can be moved to a different grinder and get the same results (within the run out error of the shaft) which should be good enough for most bench work.

What am I missing?

Your drawing is exactly the way even the cheapest bench grinders come from China.

Jack

 

[jschmidling]

I never had much luck with those dressers either. The T shaped diamond dresser that Mikey mentions is what works best for me too.

I have one of those but it suffers from the same problem, i.e. hand holding it will never make the wheel round. It just follows the contour.

How do you position it to just kiss the high places? The photo posted by Roy makes sense because it is used with a controlled tool rest. I assume the diamond is at the end of the pointed screw.

Jack

 

[pstemari]

You don't need to jam it into the wheel with a lot of force. Rest the T dresser or a dressing stick on the tool rest and then just barely kiss the wheel.

Wear a respirator mask, and use dust collection while doing this. It makes a huge mess and I don't trust abrasive dust in my lungs in the slightest. *Supposedly* aluminum oxide is not as dangerous as crystalline silica or asbestos, but I have my doubts. There's not much your body can do with little sharp bits of mineral once they get deep in your lungs other than embed them in scar tissue

Sent from my Pixel XL using Tapatalk

 

[royesses]

I have one of those but it suffers from the same problem, i.e. hand holding it will never make the wheel round. It just follows the contour.

How do you position it to just kiss the high places? The photo posted by Roy makes sense because it is used with a controlled tool rest. I assume the diamond is at the end of the pointed screw.

Jack

Yes the diamond is at the end of the pointed screw. The shaft and diamond come as one piece. I threaded it 3/8" 24 TPI.

Roy

 

[jschmidling]

Yes the diamond is at the end of the pointed screw. The shaft and diamond come as one piece. I threaded it 3/8" 24 TPI.

Roy

I bought one of those but never quite figured out how to use it on a bench grinder.

I looked at it just now under the microscope and there does not seem to be a diamond in it. Applying it gently to the wheel just ground a flat on the end. I know there was one in there originally as I did some dressing with it. Apparently, I destroyed it. I guess your mil at a pass is about all it can take. No easy way to do that other than what you did. I suspect these things are meant for surface grinders.

Thanks for the idea,

Jack

 

[royesses]

I bought one of those but never quite figured out how to use it on a bench grinder.

I looked at it just now under the microscope and there does not seem to be a diamond in it. Applying it gently to the wheel just ground a flat on the end. I know there was one in there originally as I did some dressing with it. Apparently, I destroyed it. I guess your mil at a pass is about all it can take. No easy way to do that other than what you did.

Thanks for the idea,

Jack

Yes Jack you are correct. You can only take a couple of thousandths at a pass. Initially it can take some time to get the wheel trued. But then when it is trued it does not take many passes to keep it trued. Also it is good to eliminate as much side to side wobble as possible. I do that using adhesive dots ( like the small round price stickers used at some stores) between the wheel and flange washers. Even after turning new flange washers on the lathe there is still some wobble. I've made new washers and wheel bushings for both my 8" grinders on the lathe, trued them and corrected for wobble. I can stand a nickle on edge on the motors while running and it wont move. This makes sharpening tools so much better and you can see the difference in the sharpened edge.

Roy