CBN Wheel for Tormek

[Ken S]

Interesting! Thanks, Grepper. The images tell the tale.

Ken

[bobl]

This is so good to see as much dialog on the subject of C.B.N.
Cubic Boron Nitride
As I was one of the first to mention it !!!
Funnily enough, I see there is a T2 knife sharpening machine available. Surely this is an extension of what we are talking about??
I look forward to your views.

[SharpenADullWitt]

This is so good to see as much dialog on the subject of C.B.N.
Cubic Boron Nitride
As I was one of the first to mention it !!!
Funnily enough, I see there is a T2 knife sharpening machine available. Surely this is an extension of what we are talking about??
I look forward to your views.

If it is available or not, depends on your country.  It isn't an option in the USA.
That is certainly something we have talked about here though, although it is diamond, instead of CBN.  (still should be hard enough for the designed use)

[Ken S]

I have researched CBN wheels (online only at this point). I have several questions:

CBN wheels are designed for harder steels. As I am not an active turner and most of my chisels and plane blades are older, carbon steel, does CBN offer any cutting advantage for me? Related to this, will my carbon steel blades clog a CBN wheel?

I can imagine the CBN wheel being useful for someone like Grinder of Sweden who specializes in sharpening drill bits, which are mostly high speed  or harder. As I recall, Grinder uses a T4. Without the option of an SB wheel, CBN might be particularly interesting.

As much as some of us grumble about the stone grader, there is no stone grader for CBN wheels. Grepper's photos clearly show the flexibility of grinding with a light touch, however, we are still massaging a single grit. Most CBN wheels are marketed for turners, with 80 or 180 grits. According to Dave Schweitzer of D-Way Tools, around seventy percent of his CBN sales are the 180 grit. Those seem good choices for turners, but perhaps too coarse for other purposes. Tormek's diamond wheel for the T2 is 600 grit, about the same as Stig's preferred halfway point with the stone grader. Someone removing less steel might even prefer a wheel finer than 600 grit.

I do find the concept of CBN wheels fascinating. The idea of a grinding wheel which required neither truing or retruing is appealing. The idea of a wheel which does not wear down is also appealing. however, on a practical basis, we should factor in how much wheel we really wear down. Frankly, using a CBN wheel dry has no appeal for me. Dave Schweitzer told me his wheels may be used either wet or dry. I like the very cool, dust and spark free wet environment.

I can see a CBN wheel in my future at some point.

Ken

[grepper]

Whenever I read about CBN wheels it's hard not to get the impression that they are the holy grail of grinding.  The apex of abrasives.  The summit of sharpening!  I mean, considering low heat generation, never need truing, few sparks, no wheel dust, extreme longevity, reasonable cost, fast cutting with light pressure, dry or wet grinding, not chemically reactive with steel, no rust, can be recoated, does not get smaller with use, non-friable, high and slow speed grinding, if they load from softer steel can be cleaned by just grinding with hard steel, available in various grits, and electroplated to a metal wheel that won't corrode, deform, chip or explode, it's hard not to be impressed.  Did I miss anything? 

Thermal conductivity diamond vs CBN:
http://www.cityu.edu.hk/cosdaf/cbn_property.htm

Tool heating is not a problem unless too much pressure is used.  They cut quickly with light pressure.

From: https://www.georgiagrindingwheel.com/grindingwheels_basics.htm
We get asked quite frequently if a diamond wheel can be used on steels and CBN on carbides.  We do not recommend this as the wheel life will be greatly reduced and in some cases, the wheels may not even cut at all.   A diamond wheel is specifically used for carbides, plastics and other synthetic materials.  It will not grind steel well at all.  CBN wheels should only be used on steels.  There is a hybrid grit available that will grind both; However, it is a compromise in wheel life and grind-ability.  But in cases where you must grind both materials at the same time, it can be a real time saver.

I have read that if the wheel loads up from softer steel, they can be cleaned by just sharpening with hard steel. Nonetheless, this guy says:

From: http://azwoodturners.org/pages/tips/WhatIsCBN.pdf
What Woodturners Need to Know about CBN
Ohh, you shouldn't throw away your old aluminum carbide wheels. You'll still need them if you do any grinding of mild steel. CBN is for HSS only, not for mild steel.  Don't forget this, lest you have to buy yourself a new CBN wheel. I keep one CBN wheel on one arbor of my grinder and an aluminum oxide wheel on the other arbor of the same grinder, and it works out fine for me.

Prices are falling and they are readily available from non-China manufacturing sources.

One Example:

OptiGrind, manufactured in Austria, available in U.S. and Europe.  $220.00 U.S.
http://optigrind.com/ourshop/prod_5389018-8-x-15-inch-CBN-Grinding-Wheel-200x40x32-fine.html

https://www.amazon.com/OptiGrind-Grinding-Wheel-Slow-Speed-Grinders/dp/B00LX2KD74/ref=sr_1_7?s=hi&ie=UTF8&qid=1479574014&sr=1-7&keywords=cbn+grinding+wheels

https://www.dictum.com/en/sharpening/grinders-accessories/sharpening-devices-for-grinders/704887/optigrind-cbn-grinding-wheel-oe-250-x-40-mm-super-fine#

[Elden]

   Since diamond wheels are not used for steel, why do DMT, Wicked Edge, and others used diamonds in their stones? I am not saying that the wheels can do it, is it the speed difference?
   I would like to try a CBN wheel on my chainsaw grinder, however, I am afraid to try it. I see positive and negative reviews. My concern is about wheel concentricity. The resin and vitrified bonded wheels that I use now, require dressing to true them to the machine. Will the CBN wheels be absolutely true or will they be defective in concentricity as the above wheel is in concavity? At 3450 rpm, concentricity is needed. Even if the wheel surface is concentric with its arbor hole, the inner flange on the grinder could be non-concentric with the motor shaft. The grinding wheel sits on a shoulder that is part of that flange instead of the motor shaft. Oh, that has nothing to do with Tormek, by the way! 

[Jan]

Elden, I think your comment is relevant also for Tormek despite the slow rpm! 

Thanks for the nice review, Grepper! 

From my point of view the greatest advantage of CBN wheels for TORMEK sharpeners is fast cutting with light pressure and wheel longevity. No need for the sophisticated TTS-100. Simple wooden bloc would be sufficient for edge angle setting.

The fact that CBN never needs truing is fine but on the other hand the Tormek truing procedure guarantees that the stone is true with respect to my USB. Tormek truing is immune to minor misalignments between USB and the grindstone axis. For CBN wheel there is no such a guarantee. 

Jan

[grepper]

I would like to try a CBN wheel on my chainsaw grinder, however, I am afraid to try it...  Even if the wheel surface is concentric with its arbor hole, the inner flange on the grinder could be non-concentric with the motor shaft. The grinding wheel sits on a shoulder that is part of that flange instead of the motor shaft.

Due to the fact that the CBN wheels are machined, they should be concentric, balanced and true.  As you probably know they make them for chainsaw sharpeners, but they are a little pricy, ~$100.00 or so, but would probably be the last one you need to buy.  Could you point us to a negative review?  I'd be interested in reading that.

What make/model of sharpener do you have?

If your machine requires something other than concentric, balanced and true then, well, that would be a problem.  I'd suggest contacting the manufacturer of your sharpener if you suspect there might be issues.

The manufacturing quality of "some" CBN wheels can be questionable.  You might want to check out where they were manufactured if you are going to try one, and be sure that you could return it if there were issues.

[Ken S]

Interesting comments, all.

The thought occurred to me that the original Tormek grinding wheels, the ones made from natural stone, had to do all the duty. There was no stone grader or leather honing wheel. The aluminum oxide SG wheel was introduced, offering a coarser stone which could be graded finer. The leather honing wheel offered polishing.

For many years this combination of one gradable stone and the leather honing wheel had to cover the waterfront. Then Tormek and others offered several more specialized grinding wheels. Some of the burden was lifted from the SG.

Now we have CBN, which adds new dimensions. We now have a happy situation where no one grinding wheel has to cover the entire waterfront. If one wheel works well for high speed steel and not well for softer steel, we just EZYunlock it and replace it with a more suitable wheel. So, let's enjoy the pros and EZYunlock most of the cons.

Ken

[grepper]

A wise, encompassing, interesting and right-on perspective of the purpose and evolution of the grinding wheels there Mr. Ken!

Of course I can't know it, but I am a student of Zen.  "EZYunlock".    My new word and yin yang life lesson for the day.

It never occurred to me before that the top and bottom represent grinding wheels.  But then I'm always busy looking for the camel while riding on its back.

[Ken S]

This topic becomes increasingly interesting.

Klaus (Waterstone), thank you for posting the Derek Cohen link. I have found Derek's posts very informative, but missed that one. I recommend using the back arrows and reading through Derek's other posts.

Derek made an interesting comment about the 3X wheel. He stopped using it because of the amount of dust it put in the air. Good point. Since I use mine wet with the Tormek, I don't think about dust. A higher speed dry grinder will grind faster than the Tormek, however, I do not have the down time keeping the tool cool with the Tormek.

Wootz, when I reshaped a turning gouge with the 3X wheel, I created a deep hollow in the stone. This was about two millimeters deep, and was the product of the reshaping and earlier use. At the time, I was unsure how to dress the 3X wheel used on the Tormek. Were you sharpening turning gouges with your CBN wheel?

Incidentally, I agree with Grepper. With such a long lasting tool, I would return it and try to get a flat wheel.

In my post with the questions, I edited out one question: which size CBN wheel? Obviously, the larger size is more efficient with the larger Tormek. In my case, I happen to also have a T4. T4 users do not presently have the option of using the SB blackstone. A CBN would be a very nice addition.

Grepper's post gave me an idea to solve the bench height problem. Now, when I need a lower bench height, I just levitate....

Ken

[grepper]

Grepper's post gave me an idea to solve the bench height problem. Now, when I need a lower bench height, I just levitate....

Done properly, it is possible to drop an uncooked chicken egg from 3 feet in the air onto bare concrete without it breaking.

How?

[Ken S]

Focus your mind.....

[Ken S]

In the end of this youtube, Dave Schweitzer discusses sharpening carbide turning inserts. He states that CBN is designed for magnetic materials like steel, however, it will work for occasional light touch ups with carbide. This is the same recommendation with the SB-250.

Ken

https://m.youtube.com/watch?v=XdF9mmJtuvU

[Rem]

Done properly, it is possible to drop an uncooked chicken egg from 3 feet in the air onto bare concrete without it breaking.

How?

Wrap it in bubble wrap first ??