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CBN self aligning spherical washers?

B

Barry Larson

Joined
Jan 23, 2023
Messages
206
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324
Location
Calgary, AB
I am just about to order a set of CBN wheels (180 and 600 grit) for a stripped down 1 hp slow-speed Rikon grinder I bought. The website lists self aligning spherical washers for the wheels and I am wondering how important these are to the performance of the CBN wheels?
Any and all information is appreciated.
Thank you.
Barry W. Larson
Calgary, Alberta (currently in S. Ontario), Canada eh!
 
I would vote for very important ... I used them on mine, came with the wheels. From a Google search ... for what it's worth ...

"...... Spherical washers are designed to correct misalignment between bolted surfaces. The self-aligning feature of spherical washers is crucial because it allows the washers to automatically adjust to angular misalignments between surfaces, which ensures even load distribution, reducing stress on fasteners and preventing damage to components in applications where surfaces are not perfectly parallel. By compensating for these misalignments, the self-aligning feature enhances the performance, durability, and safety of assemblies, especially in industries like automotive, aerospace, heavy machinery, and construction. This feature is essential for maintaining the integrity and efficiency of bolted connections under dynamic and heavy loads. ....."
 
Personally, I would say very important, If you dont use them the pitch of thread on the nut causes the wheel to follow the thread pitch and puts it a slight angle causing a slight wobble and vibration. which then transfers to your tool as a slight vibration
 
Steven Borruso said:
I would vote for very important ... I used them on mine, came with the wheels. From a Google search ... for what it's worth ...

"...... Spherical washers are designed to correct misalignment between bolted surfaces. The self-aligning feature of spherical washers is crucial because it allows the washers to automatically adjust to angular misalignments between surfaces, which ensures even load distribution, reducing stress on fasteners and preventing damage to components in applications where surfaces are not perfectly parallel. By compensating for these misalignments, the self-aligning feature enhances the performance, durability, and safety of assemblies, especially in industries like automotive, aerospace, heavy machinery, and construction. This feature is essential for maintaining the integrity and efficiency of bolted connections under dynamic and heavy loads. ....."
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Thanks Steven. I will acquire the washers to go with the wheels!

Cheers.
Barry
 
Well im on my 4th cbn wheel on various grinders. Have not used anything other than the original washers. My personal feeling is you only need thise washers if the wheel does not run true.
 
john lucas said:
Well im on my 4th cbn wheel on various grinders. Have not used anything other than the original washers. My personal feeling is you only need thise washers if the wheel does not run true.
Click to expand...

That may be true. I've used them on every CBN wheel I've had, bought all the wheels from Ken Rizza at Woodturners Wonders. He sold the spherical washers for cheap.

I've never even tried mounting a wheel without the washers.

JKJ
 
The problem with nuts on most grinders is that they are not "precision machined" items. This is like the stamped steel washers you get at the big box stores. This means that they can induce run out in your grinder wheels. My Baldor grinders don't need the helical (I think that is what Ken calls them) washers, but that is to be expected from Baldor. The Rikon grinders do need them. Not sure about other brands....

robo hippy
 
I've used the spherical washers on stationary mountings, never on a rotating application like on a bench grinder though. The washers I've used and seen only have a machined surface finish, not precision ground.

What exactly are you correcting? Wheel wobble or radial run out? I can see the wobble problem being corrected. Not so sure about the radial issue.

I'd like to see the results of a dial indicator test on the outside surface of the wheel using the washers. Some caution has to be used to indicate the grit area. Maybe aluminum foil between the indicator tip and the grits. I'd also like to see the same indicator test on a wheel with no spherical washers and no obvious wobble.

Based on my experience with industrial surface and tool grinding I'm skeptical about the combination of plated CBN wheels and low quality grinders like Rikon. If anyone asked me I'd recommend the proper composite tool grinding wheel with a quality grinder with a method of precision dressing the wheel.
 
Barry Larson said:
I am just about to order a set of CBN wheels (180 and 600 grit) for a stripped down 1 hp slow-speed Rikon grinder I bought. The website lists self aligning spherical washers for the wheels and I am wondering how important these are to the performance of the CBN wheels?
Any and all information is appreciated.
Thank you.
Barry W. Larson
Calgary, Alberta (currently in S. Ontario), Canada eh!
Click to expand...
for $7.00 I wouldn't give it any thought... just order them. can't hurt
 
Always worth using! However, usually you have to re-adjust things a few times to optimize their performance. Follow the directions using a very light coat of grease (not oil) between them with the heavier spherical washer against the wheel. Then, be prepared to loosen the nut and move the washers around a bit between themselves to help them find "the sweet spot" against each other and the respective wheel. I also try to center them on the shaft with my fingertips to keep it as balanced as possible.
 
David Heinlen said:
Always worth using! However, usually you have to re-adjust things a few times to optimize their performance. Follow the directions using a very light coat of grease (not oil) between them with the heavier spherical washer against the wheel. Then, be prepared to loosen the nut and move the washers around a bit between themselves to help them find "the sweet spot" against each other and the respective wheel. I also try to center them on the shaft with my fingertips to keep it as balanced as possible.
Click to expand...
David:
Thank you for the advice on how to use the washers. I had an idea that that is how they worked, but didn't know for sure.
Cheers.
Barry
 
The reason for using spherical washers isn't for even load distribution; it's to compensate for excessive play between the shaft and the hole in the grinding wheel. Spherical washers will force the wheel to align perpendicular to the grinder shaft.
 
In the real world of hobby woodturning not everyone can afford or will pay the price for a quality high-end grinder - a good 1hp Baldor might cost $2500 or more. Most of us buy less expensive Rikon, Dewalt, and the once common no-name grinders from Woodcraft.
Even if not perfect, these are fine for conventional AlOx wheels that can be trued by dressing. Of course, you can't true up a CBN wheel by dressing.

In particular, I found the nuts and cheap washers that come with cheap grinders were not always perfect. Seemed to me the nuts were more often the problem. Sometimes it felt like there was play in the threads before tightening.

I found that the inexpensive spherical washers nicely took care of any problems and allowed the CBN wheels to turn true. I think so far I've bought and mounted 8 or 10 CBN wheels before settling on the the 3 wheels I use now. I gave the rest away. (with the spherical washers if the person didn't have them) I can't promise anything for others, but as I mentioned in a previous message the inexpensive spherical washers from Ken Rizza ALWAYS made the CBN wheels run perfectly true. For me. I can think of no good reason for me to NOT use them.

Sure, try your new CBN wheels without the washers and if fine, fine. If not, maybe get and try the spherical washers. The cost is WAY less than a can of finish or a cheap gouge.

JKJ
 
Tim Hunter said:
Define “better than stock”. Quality grinders will have accurately machined flanges and nuts.

Tim
Click to expand...
Baldors for everyone!

Good thing I bought mine a couple decades ago when they were still affordable. But even though its flange washers are many times thicker than garden variety washers, they still look to be pressed/stamped, with contact surfaces that may have been faced in some way. That's why I was wondering if you knew of better aftermarket nuts and washers.

Edit- these "bench grinder arbor washers" (web term search) may fit the upgrade definition.

Shop – Crown Kirk

crownkirk.com crownkirk.com
 
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If you are experiencing run out with a CBN wheel, it is not the wheel since they all come spin and bubble balanced. I guess if you wanted to upgrade the nuts that come with the grinder you could mount them in a chuck and flatten the faces of the nut, probably needing to do both sides. A spacer may be needed. You can mount a hex nut in a chuck no problem, with a corner in/on each of the 4 jaws. This would give you a flat face to mount against the wheel. Not sure if you can find "machined" nuts, other than through a specialty store, and you would need one standard thread, and one reverse thread. They do make a difference.

robo hippy
 
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