CBN vs diamond grinding wheels

[Prashun Patel]

I'm turned on by the recent discussions about CBN grinding wheels. I've noticed on Dway's website, they don't offer a 6" CBN wheel, but rather a diamond one. Will this perform similarly? Or should I consider elevating my 6" grinder so that it'll hold an 8" wheel? Is that just crazy talk?

[John Keeton]

Prashun, CBN is designed for HSS, and the diamond is not. Were it me, I would upgrade the grinder. Besides, I think you would notice a discernible difference in the radius of the grind on the bevel. I notice that Woodcraft, at least the local one, has their slow speed grinder on sale for $90.

[Roger Chandler]

+1 on John's advice...........an 8 inch wheel will give you a better bevel and side radius for your gouges. Woodcraft sent me an email with the $89.00 price on their slow speed grinder.

[Reed Gray]

A couple of months ago, Bill Neddow did an article for the AAW magazine on grinding wheels. I researched the 'ultimate' grinding wheel some years back, talking to Amplex, Norton, and others. Their consensus was that Diamond is great for carbide, but CBN is made for steel. Because the steels are softer than the carbides, they tend to clog up the wheels, and you can't clean them. There is a guy from Quebec who makes them as well, and I talked to him at the Symposium. He said that it is more of a problem with the HSS than it is with the fancy powder metals.

I have never been able to figure out if the smaller concave shape on the bevel makes any real difference or not. On the outside of the bowl, it would make little difference unless the shape is more plate like, rather than rounded. On the inside, if you relieve/grind away half of the bevel, it wouldn't make much difference. A lot of people use them, and when finished, their bowls look as good as mine.

If you do get the CBN wheels from D Way, you will love them. They don't need to be balanced, they don't need to be trued up, they don't need to be cleaned, they last way longer than other wheels, and there is never any risk that they will break apart/blow up.

robo hippy

[Joe Vincent 63]

Reed, in an earlier post you were concerned with the tool edge looking rough after using the CBN wheels. That caused me to stop looking at them to replace the ones I have. You thought they should have been very clean, and I would agree. Do you still feel that way after using them for a while?

Joe

[Reed Gray]

By rough, I meant that it was rougher than my matrix style CBN wheels. My 150 grit leaves a surface that looks like it has been honed. My 180 grit D Way wheel looks more like 120 grit aluminum oxide, but it has been a long while since I used one of those wheels. They are worth every penny, and then some.

I was talking with Mike Mahoney the other night, and I mentioned that it looked like he used a pretty coarse wheel. He said he preferred a more serrated edge for cutting dry wood, and he preferred the 80 grit D Way wheel. That sucker can flat remove some steel. It cuts faster than the 30 grit wheel that came standard on my Baldor grinder. I have to test out the 'more serrated' cutting edges.

Heavy sigh, always some thing new to try out!!!!

robo hippy

[Prashun Patel]

Thanks, All. How about the other question?:

Can I just put a platform under my 6" grinder to accomodate 8" wheels?

[Reed Gray]

You might be able to do that. It would depend on the housing that normally goes around the grinding wheel. Also, consider that a 6 inch grinder is designed to run 6 inch wheels, and an 8 inch wheel, over time would probably wear out the motor fairly quickly. Best bet would be to get an 8 inch grinder. Another option might be to find a motor with the proper sized shaft (I would want 1/2 inch minimum) that is also slow speed, mount it on a platform, then use it. The housing around the wheel is there for when the matrix wheels crack and break. I haven't heard of any turners having that happen, but with the metal hubs, that would be pretty much impossible.

robo hippy

[Bill Neddow]

Heavy sigh, always some thing new to try out!!!!

robo hippy

That is what makes it fun!!! (and keeps me from ever hoping to make a profit)

[Joe Vincent 63]

Thanks for the clarification. Where did you get the 150 grit you are referring to?

Joe

[Reed Gray]

Joe,
I had my original CBN matrix wheels made here in Eugene, Northwest Super Abrasives. If you are interested, I can put you in touch with them, or their phone number was in a recent AAW Magazine article on grinding wheels.

Woodcraft has a matrix style diamond wheel that they sell. Cindy Drozda uses one, and recently posted about how she cleans them with a oil bath from a vegetable based motor oil. I think you can find that on You Tube. My cost for my 150 grit wheel was $300. Now that the 180 grit wheel has broken in a bit, it looks smoother.

robo hippy