CBN update, including for T4

[Ken S]

When I wrote my CBN review a couple years ago, I contacted two vendors, woodturnerswonders and D-Way. My intention was to test both brands using the Tormek wet and dry. Ken Rizza of woodturnerswonders informed me that his wheels should only be used dry. His website also stated that using them wet would void the warranty. Dave Sweitzer of D-Way told me his wheels could be used wet or dry. This information, combined with only D-Way making wheels to fit my T4, caused me to proceed with only D-Way wheels.

I purchased a D-Way 180 grit wheel for my T4. Dave also loaned me 80 and 180 grit wheels for my T8, which I later purchased. I reviewed only the D-Way wheels.

I just learned from Ken Rizza that his woodturnerswonders wheels can be used wet with the Tormek. He adds the caution that they should be used with an antioxidant solution, just like the D-Way wheels and Tormek diamond wheels should be used. He also stipulates that they should be dried off after use. Again, this is good practice with any CBN or diamond wheel. I advised him that I would correct my review to reflect the new information.

I understand why a vendor would be reluctant to have his wheels used wet. Not all users would be careful enough to use antioxidant solution and dry off the wheels.

Ken also told me that he just received his first order of CBN wheels for the T4. They are 8x1.5 inches with a 12mm bore, an ideal fit for the T4. They should soon be on his website. I do not know grit sizes. Another new accessory is a 5/8" to 12mm reducing bushing. This will allow any of the present lineup of eight inch CBN wheels to be used with a Tormek. (12mm spacer or fender washers may be necessary. They are available in hardware stores.) One of these reducing bushings would be a real improvement over my primitive reamed out plastic pipe solution for Norton 3X wheels.

I am pleased to see that more CBN wheels can be used wet, the way a wheel should be used with the Tormek. I am very pleased to see more CBN wheels available for the T4.

When I write reviews, I try to present the information fairly and objectively. When facts change, I feel obligated to update the reviews.

Ken

[GKC]

Thanks for the update Ken.  I am glad that Ken Rizza has spoken about this with you.  I think that he is being too conservative with his strict warnings against using the wheels wet, when it is really just rust that is the problem, not water.  But like you, I can see his conundrum: customers are sure to fail or forget to use and antioxidant additive and then complain to him about the rust.

As I have noted before, I got my CBN wheels to use dry (to keep the raw wood knife handles dry) but use them wet on tools that I don't mind getting wet.  I have been surprised to find that I don't mind using the wheels dry.  It runs against my instinct, but I have gotten used to the sound and the grind scratch pattern looks the same to me.  I don't sense any appreciable airborne particulates and I get the feeling that they grind faster when dry.  But that might just be me reading my assumption into the result, I haven't tried to test it.

It is good to hear about the bushings, but I was on the verge of justifying a hobbyist metal lathe to make x" to 12mm bushings; now I will have to conjure up some other pressing need.

Gord

[bisonbladesharpening]

Does the grit on the CBN wheels eventually wear out.
If so, what is the expected life and/or can they be refurbished
by the manufacturer?

Best Wishes
Tim

[Ken S]

Good question, Tim. I forwarded this topic to a major CBN wheel vendor. I will post his reply.

Ken

[Ken S]

Here is a link to the new CBN wheels for the T4:

https://woodturnerswonders.com/products/tornado-jr-cbn-wheel-12-mm-arbor

Ken

[Ken S]

Tim,

Here is Ken Rizza's reply to your longevity wuestion:

"Hi Ken- thanks for the email update.  I did go in and read it all.  Well done.  Regarding the longevity its a hard question.  Anything abrasive is going to wear out at some point and it is a function of use, care, and materials being ground.  A popular wood turning tool manufacturer uses CBN wheels in his factory to profile his tools before shipping them out.  His grinder never shuts off during the day and they last him about a year.  That is a lot of grinding which compared to most wood turners would translate to years I would think.  It isn't economically feasible to re-coat them I don't believe. We are the same age so I don't even buy green bananas anymore.  😱☺"


On a practical level, the T4 size CBN wheels cost just under twice the price of a replacement SG-200. Costwise, if a CBN lasts more than twice as long as an SG-200, it becomes cost effective. I have no doubt that the useful life of a CBN wheel is far longer than two times the useful life of the SG-200. This does not take into account the cutting rate of a CBN wheel or the advantages of using the side for flat grinding.

I have no illusion of any grinding wheel lasting "forever". I do believe that an occasional user like me will probably expire before the CBN wheel expires.

Ken

[Elden]

   To me there is another factor that should be considered. What happens if the wheel gets messed up? For instance falling off a farmer's my table (did I read that some where?) or slip from one's hand? What then?
   This is comparing apples to oranges, but I do a fair amount of chainsaw chain sharpening. I would really like to try a CBN wheel on my chain grinder, but I am afraid to. Why? Because I have broken several grinding wheels by various accidents. Yes, mostly because I got into them with my wheel chair. But when a CBN wheel costs 10 times more than a regular wheel for my chainsaw grinder.......🤔
   The wheels for the Tormek are many times thicker than the chainsaw wheels.
It might be that the CBN wheel for the Tormek might withstand more abuse than SG?.
   These are just some rambling thoughts.

[Ken S]

Elden,

You raise an interesting issue. No doubt, you are aware of the ring test in traditional dry grinding. It is good practice (for safety) to hold a new or newly acquired grinding wheel with a rod through the bore. The side of the wheel is then tapped with a wrench. An undamaged wheel will give off a ringing sound. A  wheel with an internal crack will give off a thud sound.

A ceramic grinding wheel, like a ceramic plate or cup, can crack if dropped. A CBN wheel is made like a machined pulley, with a machined steel or 6061 aluminum body. I can't imagine one cracking, although I can envision one possibly bending if hit with enough force.

I have never sharpened a chain saw chain. I have seen someone sharpen one with a file and flexible shaft Foredom grinder. I have no idea what grinding wheels, either ceramic or CBN, for a chain grinder might look like or cost. You know better than I do, what is the probability of bending a chain grinding wheel?

Sharpening chain saw chains might become a profitable side line for some of our members with a sharpening business.

Ken

[RickKrung]

   To me there is another factor that should be considered. What happens if the wheel gets messed up? For instance falling off a farmer's my table (did I read that some where?) or slip from one's hand? What then?
...snip...

Elden,

That was me, an SJ wheel fell off of a folding table that collapsed as I was loading up at the end of a farmer's market activity.  Cracked it beyond use/repair.  Still have not replaced it. 

I agree with Ken about a metal grinding wheel probably not cracking, but I can see it getting dented in such a way as to be not usable.  I would not want to have any of my Tormek diamond wheels fall that way. 

Rick

[Elden]

Ken,

   I am acquainted with ring testing. Attached are a couple of pictures which will give a fair idea of a CBN wheel for chainsaw grinding. The two common thicknesses that I use are 1/8" and 3/16". When a handle on a power wheel chair connects with a regular grinding wheel, they are broken before one knows what is happening. While the CBN probably would not break, I think they would bend very easily.  0.125" (1 /8") and 0.1875" (3/16") are not very thick. A bent chainsaw grinding wheel would practically worthless.

   The CBN wheels would be much more substantial to applied side pressure. I can not help wonder what damage would be sustained if the wheel was dropped on the face. Simply said, do not ever drop it and find out! However, dropping things occur regularly with me.


Rick,

   I knew it was either you or Rich. Didn't take it the time to look it up. That makes all of us feel sick for you.

Best regards,
Elden

[Ken S]

Elden,

Is the difficulty the wheel or the way the chain grinder is secured to your wheelchair?

Ken

[Elden]

Ken,

   The grinders (2 of them) are mounted onto a 7/16" piece of wafer board using bolts and T nuts. That is clamped to the shop work bench. When the weather is nice, it can be clamped to an outside table / work bench. The problem is when I spin around without paying enough attention to what I am doing. I have snapped a couple or so due to the lack of proper attentiveness.  Recently it has not been as much of a problem due to more open floor space and the dreaded extended handles are not on my current chair. Not sure why they were ever put on a power chair!

   The grinder head sticks out beyond the edge of the work bench. The chain does not contact the bench, but hangs down toward the floor. Attaching another photo that was online. While this picture shows it mounted on its own stand, you can get the idea of how it would be mounted on a bench.

   This is a personal problem that has nothing to do with the Tormek. It just made me wonder what would happen to any CBN wheel that happened to get dropped, particularly on the grinding face.

Elden

[Ken S]

Elden,

I could have used your help several years ago. I hired a tree trimmer to remove several ash trees which had been infected and died. I had no idea that the previous owner had tried to "fix" the problem by filling one of the trees with concrete. The concrete and the chainsaw did not play nicely together.

Maybe you should post speed limit signs in your shop to slow that cowboy driver........

Ken

[Elden]

Ah, the joys of not knowing what is hidden inside of a tree! One of my son's first jobs, had a tree with a steel T fence post buried inside of it. Of course, it wasn't visible, either. It just happened to be a new chain.

[RichColvin]

Ken,

Any idea why CBN wheel vendors say not to use them in water ?

Kind regards,
Rich