This thread continues the discussion started here http://forum.tormek.com/index.php?topic=2831.45 (http://forum.tormek.com/index.php?topic=2831.45) where grepper gave excellent summary on CBN wheels.
My wheel came from http://woodturnerswonders.com/collections/tormek-cbn-wheels/products/tormek-cbn-wheel-600-grit-10-x-2-inch-12mm-arbor (http://woodturnerswonders.com/collections/tormek-cbn-wheels/products/tormek-cbn-wheel-600-grit-10-x-2-inch-12mm-arbor)
The original stone of the Tormek T7 has a diameter of 250 mm, the CBN wheel has a diameter of 254 mm. At first I thought it is just a little too big for the water trough, but it fits fine, though almost flash, and runs without brushing the trough.
With the width of 50.8 mm, the shaft protrudes just enough to tighten, as seen on the next photo.
(http://home.exetel.com.au/dropbox/CBNwheel1.JPG)
The CBN wheel bore matches the Tormek's shaft, mounts square and runs perfectly round, and no lateral wobbling whatsoever.
Weighs 1920 g, i.e. less than half of the stone, runs effortlessly.
The grit is coarser than the stated 600, feels and grinds like ANSI/JIS #300.
They say the boron nitride crystals don't crash as easily as diamonds with use, so I wouldn't expect the grit to settle down much.
The CBN wheel looks fascinating on the Tormek, like a tamed milky way, and gives a clear bell ring when struck with a finger nail, reminiscent of Buddha temples.
Unfortunately, the CBN wheel of this make has grinding surface somewhat saddle-like, concaving from sides to the middle; not much, yet you can see it with a naked eye.
And this is really disappointing, as otherwise the wheel is so good.
(http://home.exetel.com.au/dropbox/CBNwheel3.JPG)
(http://home.exetel.com.au/dropbox/CBNwheel4.JPG)
On the few knives I have tried so far, the wheel middle part don't even reach the blade; as a result the heel and tip sections of the blade risk overgrinding.
Because of that you cannot really run it dry; you need a water flow to show points of contact with the wheel, and adjust sharpening routine to compensate for that.
Since I read that the boron nitride particles can cause pneumoconiosis when inhaled, I will not run it dry anyway.
As to the CBN grinding ability, I liked how fast it ground the ceramic and Bohler Vanadis-10 (the hardest blades I got at hand).
Better than anything else we use with Tormek.
Wootz – Thanks for the follow up!
"Unfortunately, the CBN wheel of this make has grinding surface that is somewhat saddle-like, concaving from sides to the middle; not much, yet you can see it with a naked eye.
And this is really disappointing, as otherwise the wheel is so good."
I would be very disappointed too! Especially considering that it will always be that way and there is nothing you can do about it. I would consider it to be a problem, contact the dealer, inquire if that is normal, and consider returning it. I would ask the dealer to put a flat edge on other wheels they have in stock and see if they have a flat one. Sharpening only on the edges of the wheel just can't pan out all that well.
From all the reviews I read, you will have that wheel for a really long time, if not indefinitely. Considering that, even though returns are a pain, you might as well start out with a flat one! I'm saddened and actually surprised to see that. I would think that since those are metal wheels they would be nearly perfectly manufactured. :(
"They say the boron nitride crystals don't crash as easily as diamonds with use, so I wouldn't expect the grit to settle down much."
Again, only from reviews I read, many said they do settle down after a month or two of use. It will be interesting to hear your periodic observations over time.
How do you like the lack of wheel goop in the trough an around the machine? I would think that would be a big plus.
Thanks again for the follow up, and keep us informed!
I guess you get what you pay for?! :o
This saddle-backed shape was completely unexpected, moreover that the wheel is machined precisely otherwise.
The WoodTurners Wonders are responsive, but it makes little sense to return this particular wheel, as all their 10" wheels seem to be the same.
They suppose this might be due to electroplating done wrong, and that they "have contacted the factory to ask them about this and I will get back to you."
I really like how mess-free this CBN wheel is compared to the stone.
And effective. I didn't see much difference between the CBN and SG on a mainstream kitchen knife, but did appreciate it as started sharpening the harder steels.
Am now in quest for a truly straight and finer CBN wheel.
After seeing your surprising review, I did some searching around and found only 1 or two old reports of wheel surface concavity. I would think that if this was a common problem it would be all over the web. Others reviews stating their wheels are "dead flat", etc. It also was not clear if the problem wheels were the older bonded surface or the more stable electroplated variety.
Good to hear that your dealer is responsive. IMHO, an electroplated CBN wheel with an anything but flat surface is not acceptable, even if they have others that are the same. It could just be a bad batch, specially imported from the Orient.
So don't give up on Woodturners and get a correctly manufactured wheel. Those things are not exactly inexpensive and ones with a flat surface are available.
Please keep us informed!
Thank you
Maybe you know Derek Cohen, an Australian furniture maker and tool maniac. He had similar issues with CBN wheels. He's running them on a dry grinder but the point is the same.
http://www.inthewoodshop.com/WoodworkTechniques/UltimateGrindingSharpeningSetUp.html
Klaus
I don't know, but I suspect that the wheel in that article is a bonded CBN wheel as opposed to an electroplated wheel.
I'm like totally not an expert at all in CBN wheels so it would be cool if somebody who is would post. I mean, there is every chance that I don't know at all what I'm talking about. ::)
It is my understanding that bonded CBN wheels have a coating of CBN impregnated resin bonded to the surface of the wheel. This bonded layer can be somewhere between 1.5mm and 6.5mm thick. Bonded wheels are actually friable, and can be dressed. A bonded substrate could continue to be abrasive even if it became dished because the bonding layer is fully impregnated with CBN.
Electroplated CBN wheels have a mono layer of CBN crystals fused to the surface of the wheel in a layer of nickel electroplate, the thickness of which is determined by the size of the abrasive.
http://www.breu-diatools.com/en/production-process/
Nickel is not all that hard, somewhere between 48 and 58 HRC depending on treatment, but CBN is bested only by diamond as far as stuff we can use hardness goes... Pretty tough stuff.
From my totally uninformed perspective, I can understand how a bonded wheel could become dished as the resin substrate is abraded away, but it would seem that the only way an electroplated wheel could become significantly dished would be if the CBN layer was compromised exposing the relatively soft nickel electroplate and wheel material, or if the wheel was badly manufactured with a concave surface to begin with.
Anyway, that's why I suspect the wheel in the article is bonded rather than electroplated. Just a guess.
Wootz, great trailblazing work!
Grepper, excellent informed commentary!
The saddle shape seems an unnecessary frustration for an otherwise outstanding product. I found a well done article on dry grinding which advocates dressing a slight crown on the grinding wheel instead of leaving it flat. The purpose of the crown is to limit the actual grinding to a smalller point of contact, thus limiting the heat production. I don't know that this crown technique would work with all tools. It should work with flat edges like chisels and planes. And knives. I would rather have a crown than a saddle.
I am surprised that the saddle effect is not eliminated during production. Surely a factory inspector would have access to basic tools like a straight edge.
A test request for the microscope brigade: Using either identical tools or different sections of the same edge, would you please make photos showing the difference in the surface roughness when the final pass or two is made using avery light touch? Depending on how much difference is shown, varying the touch could potentially add to the usable range of a "single grit" grinding wheel.
My family is awakening. .Must dash.
Ken
These links seems informative.
https://www.youtube.com/watch?v=WDFGa9pxCgQ
https://www.youtube.com/watch?v=-nQxfT5kumE
Be sure to pay attention to what Ernie says about CBN and mild steel. These are not wheels for every use.
This video offered some good thoughts for choosing dry grinders to use with CBN wheels.
https://www.youtube.com/watch?v=CDNNEDjFcag
Ken
I did a bunch of searching around trying to find the thickness of the abrasive/bond layer of electroplated CBN wheels. As far as I can tell the thickness of the layer is primarily determined by the size of the CBN crystals due to the fact that the abrasive layer is comprised of only a single layer of abrasive crystals bonded in nickel electroplate. I only found two references, one being 0.07 mm (0.0028"), and the other 0.05 mm (.002").
(http://i1275.photobucket.com/albums/y441/grepper00/bond%202_zpsu09fjtpq.png)
From: http://blog.cdtusa.net/cbn
(http://i1275.photobucket.com/albums/y441/grepper00/electro_zpsyqe5r00u.png)
Can you see 0.05 mm with the naked eye? Yes, but it is very minimal, especially in comparison to the irregular surface of grinding wheel. Use a caliper or feeler gauge and check it out.
Moreover, assuming the wheel was flat to begin with, having even a 0.05 mm concavity would require the entire abrasive and metal bond layer to be completely removed. If just the abrasive itself became slightly worn down, the deviation from flatness would be only a portion of the total layer thickness and would start to border on being imperceptible. For general tool edge grinding it would be more or less irrelevant.
In Mr. Wootz' wheel, it seems a reasonable conclusion that the surface irregularity is due either to very poor and uneven electroplating, and/or the wheel surface was unevenly manufactured. I believe Tornado wheels are manufactured in China, so I don't think that sloppy manufacturing and inconsistency in production runs is all that surprising.
Quote from: Waterstone on November 16, 2016, 06:22:54 AM
Maybe you know Derek Cohen, an Australian furniture maker and tool maniac. He had similar issues with CBN wheels. He's running them on a dry grinder but the point is the same.
http://www.inthewoodshop.com/WoodworkTechniques/UltimateGrindingSharpeningSetUp.html
Klaus
Appreciate your input, Klaus.
Issues with CBN wheels quality appear to be a broader problem than I thought.
Factories supplying US dealers seem not to bother with QA.
Ordering a CBN wheel without a pre-sale inspection is a throw of a dice in regard to the quality.
To his credit, Ken from WoodTurners Wonders took my case to the manufacturer, and if they can fix their process, will do pre-dispatch inspection for me to assure the wheel is flat-faced.
BTW, neither labels on the wheel and packaging, nor WoodTurners Wonders say anywhere that their CBN wheels are sourced from Eastern Asia.
Thank you guys for your support
Mr. Wootz - Glad to hear that! It's also good to hear, if I am interpreting you correctly, that Woodturners is standing behind their product and you will end up with a good wheel. Good for them! If Tormek produced CBN wheels, (hint, hint) you probably wouldn't have had a problem in the first place.
As always, please post the story as it progresses!
I am 99% sure that Torando wheels are made in China. I found them on madeinchina.com.
My how times have changed. It's funny, but when I was a kid, "imported from the Orient" conjured an entirely different impression than it does today. Today, at least here in the U.S., almost everything is specially imported from the Orient.
In my kitchen cupboard there exists a box of toothpicks with a label on the side; Made in China". Really? Toothpicks? Yes, in the U.S. even toothpicks are specially imported from the Orient. Anyway, of course, many of the toothpicks are malformed and break easily when used.
A couple of years ago I purchased a plastic toolbox, specially imported from the Orient, about the right size to hold maybe 10 screwdrivers. It's about 10" x 4" x 1.5". When the box is opened, even at arms length, one's olfactory senses are assaulted by invidious effluviums that can only be described as a combination of well aged dirty socks, rotting fish and burnt hair. I would have thought that the putrid stench would have dissipated over a time, but no! It survives in all of its glory today. Doh! I am a victim of the well documented China stink plastic!
I really wish all of you guys could take a whiff so you would understand that I in no way exaggerate! Seriously, one whiff is all it would take.
https://www.youtube.com/watch?v=Q8skzjsaJc8
"Comparing apple's with apples" is an English idiom for the importance of fairly comparing things fairly on an equal footing. I have not seen this happen when comparing Tormek and dry grinders and CBN wheels.
Using the BMG-100 to adapt Tormek jigs to dry grinders is generally not an apples to apples comparison. I am not an import baster, and using the BGM with an inexpensive grinder will do an adequate job. Let's just not pretend we have found Tormek quality in a hundred dollar dry grinder. Apples with apples would be comparing Tormek with a Baldor grinder or similar.
A CBN wheel with quality materials and machining, individually balanced, will probably cost at least what an SG or SB costs. Like Wootz, I would find a grinding wheel with a saddle unsatisfactory. In fact, an article on www.toolsforworkingwood.com recommends using CBN wheels with a crown shape. (That could easily be a topic by itself.)
I look forward to the ongoing saga of using the Tormek with CBN wheels.
Ken
Quote from: Ken S on November 16, 2016, 11:39:25 AM
A test request for the microscope brigade: Using either identical tools or different sections of the same edge, would you please make photos showing the difference in the surface roughness when the final pass or two is made using avery light touch? Depending on how much difference is shown, varying the touch could potentially add to the usable range of a "single grit" grinding wheel.
I'm glad you suggested checking this out Ken. I do the same thing, even though I had never examined exactly what was actually happening and the results are interesting. I guess it just intuitively seemed like the thing to do.
I used a very coarse grind and removed enough metal so that no scratching from a previous sharpening remained. I figured that a coarse grind would best show the effects of light pressure passes over existing heavy passes at the same grit.
If I am interpreting the images correctly, the effect of light passes over heavy passes appears to do about what you would expect: The depth of the scratches, measured from the newly formed surface, is reduced as some of the high areas between scratches are abraded away. New, shallower scratches are created in previously smooth areas. Some burr material was caught and torn away.
From a more macro perspective, I think it can be compared to running a piece of cheese over a box grater, first with a heavy passes and then with lighter passes.
Anyway, here are three images. First image; heavy pressure. Second image; lighter pressure. Third image; many passes with very light pressure.
I find the third image most curious compared to the first two. I would have thought that many very light passes would further smooth the finish, but that does not appear to be what occurred. Maybe even the opposite.
Keep in mind that this was just one test, in a pretty much uncontrolled environment. But, if I were to form any conclusions from this single test, I would conclude that a couple of light passes seems to smooth the surface some, but further passes do not, and may even be regressive.
What do you think?
(http://i1275.photobucket.com/albums/y441/grepper00/01_zpscu42htpv.png)
(http://i1275.photobucket.com/albums/y441/grepper00/02_zps689gcv9g.png)
(http://i1275.photobucket.com/albums/y441/grepper00/03_zpsjgvotaj8.png)
Interesting! Thanks, Grepper. The images tell the tale.
Ken
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.
Quote from: bobl on November 19, 2016, 12:42:23 AM
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)
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
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#
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! :D
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
Quote from: Elden on November 19, 2016, 10:21:19 PM
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.
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
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.
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
Quote from: Ken S on November 20, 2016, 01:00:20 PM
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?
Focus your mind..... :)
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
Quote from: grepper on November 20, 2016, 08:37:40 PM
Quote from: Ken S on November 20, 2016, 01:00:20 PM
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 ?????
Rem,
Please note in reply #26, Grepper should get full credit for the quote.
Ken
Ken, I would never seek to usurp the credit for something of this magnitude. RR
I fully realize that, Rem. I just wanted to clear up any doubt that the source of that wisdom was our distinguished member from Michigan.
Ken
I relinquish to the superior knowledge of the G-man in virtually all matters .... with the possible exception of banjo picking. I wonder if he plays the banjo ....... we are a dying breed. And that's not necessarily a bad thing. R ;D
Rem,
At the risk of returning to the original topic, :) Here is the reply to an email I sent to Dave Schweitzer of D-Way Tools. (An earlier post correctly stated that we needed some expert advice. Dave seems like the real deal CBN expert.)
Ken,
I am not sure of the brand he has so can't comment on it. Most likely it
would have to go back to factory to be flattened.
My wheels are electroplated to a steel substrate so you can't concave the
surface.
For general wood working tools the 180 grit works great. I use a 400 grit to
sharpen my knives. I don't have them in stock, but can order other grits.
Dave
(Dave stocks 80 and 180 grit wheels.)
A later email:
Ken, got to thinking about the issue, and it could be he has resin bond
wheel, which is glued on. Resin bond does cost less.
That's a gutsy move, returning to the original topic. However, after careful consideration ..... I'll allow it. R ;)
Most gracious of you, Rem.
Quote from: Ken S on November 26, 2016, 02:42:48 AM
Here is the reply to an email I sent to Dave Schweitzer of D-Way Tools. (An earlier post correctly stated that we needed some expert advice. Dave seems like the real deal CBN expert.)
I agree. I would be cool if someone with a CBN wheel, especially someone with long term experience like Mr. Schweitzer would post here. When I read about them, they seem like the bee's knees o' sharpening and grinding. If that's true, I'm sort of surprised that we have not run into at least a few folks that have one so they could give a good review of pros and cons. I suspect it is the cost compared to traditional wheels that makes purchasing them a much greater consideration. At least that's why I don't have one.
My questions would be: Do they really last basically forever? Really? How do they work for slow speed grinding? Considering they cannot be trued, is alignment a problem with the Tormek USB? I would think that some deviation could be easily adjusted for when sharpening knives. Chisels might be a bit more difficult.
R-man. On the egg thing: It's way easier than you think. I can do it every time without fail. You can actually drop a plain, uncooked, bare, unprotected chicken egg onto concrete and it won't even crack.
Perhaps this will help:
You are a bus driver on the morning route to the train station. On the first stop 5 people get into the bus. On the second stop, 1 person gets out and 3 people get on. On the third stop, 1 person gets on and 4 people get out. One the forth stop, 2 people get on and three get out. On the last stop, 2 people get on.
What color are the bus driver's eyes?
Quote from: grepper on November 26, 2016, 06:53:03 AM
R-man. On the egg thing: It's way easier than you think. I can do it every time without fail. You can actually drop a plain, uncooked, bare, unprotected chicken egg onto concrete and it won't even crack.
As a boy I helped my grandfather with the manufacture of cement products and since then I know it is very hard to break aged concrete. :)
From my geophysical profession I can add that a low gravity environment will also solve the riddle, but it is difficult to substantially lower the gravity. ;)
Free-falling environment (elevator) was used by Albert Einstein as a cornerstone of his theory of general relativity.
Jan
The real question, Grepper, is, Do you perform your egg dropping on the kitchen floor when your wife is also there? :)
I think we need a realistic definition of "forever". I have heard that in Ohio the legal definition of a "lifetime guarantee" is seven years. One report (hearsay evidence) that I heard is that one professional turner is still using the same CBN wheel after ten years. In my shop, that would convert to three hundred years. As a point of reference, Steve Bottorff is the only one I can recall who has worn out more than one SG-250 wheels. I may have overlooked some others, however, I would not place longevity at the top of the pro side list for CBN vs Tormek wheels. I would put not having to retrue the wheel as a definite CBN plus. As a counterbalance, on the Tormek side I would place, Periodic retruing necessary, however, retruing is not difficult and is relatively quick.
Like Grepper, I am surprised that we have not run into more folks who use CBN wheels. Assuming the comment about the turner using the same CBN wheel for ten years is accurate, that would indicate that CBN wheels have been available for ten years. Another bit of hearsay evidence is another dealer's claim that he has sold thousands of CBN wheels to Tormek users. If so, they are a very quiet group. I am not doubting the claim; I just have not heard from the claimees.
Comparing my low budget Norton 3X wheel option, I would note "Cuts very quickly (both 46 and 80 grit), however one inch wheel width requires more care in use." I was able to reshape a half inch turning gouge on the narrower 3X wheel artery low cost without feeling frustrated. (In fairness, I could have worked the same reshaping into my very busy sharpening schedule gradually and used the SG or SB at no extra tooling cost.) Many thousands of turners use one inch with grinding wheels every day. I am just spoiled with the Tormek's 50mm wide flight deck.
D-Way's ten inch wheel designed for the Tormek is 1 1/2" wide. At first glance, that is narrower than the SG-250 at 50mm (~ 2"). Based on my own experience with the even narrower 3X wheels and watching several youtubes demonstrating the 1 1/2" wheels, I do not believe the narrower width is a real world constraint. I have not felt constrained using the 40mm with SG-200 on the T4.
I have occasionally been accused of overthinking. I am still overthinking the CBN wheels. I suspect my stable of grinding wheels will someday include more than one CBN wheel. I am leaning toward starting with either 180 or 400 grit. 180 is the present front runner.
I still think I prefer to use it wet with the Tormek. I am spoiled with the Tormek's dust free, spark free cool environment.
My other overthinking question, perhaps unique with me, is, Which diameter? The 1 1/2" wheel width is an exact fit with the T4. All this overthinking is tiring. :'(
Ken
Quote from: grepper on November 26, 2016, 06:53:03 AM
R-man. On the egg thing: It's way easier than you think. I can do it every time without fail. You can actually drop a plain, uncooked, bare, unprotected chicken egg onto concrete and it won't even crack.
OK, so I tried the egg thing on the kitchen floor this morning. It just made a big mess. Had to call the dog in. But the floor didn't crack.
Regarding the bus driver's eyes, they were red. It was an early morning route.
The real questions is: How do you get a banjo player out of a tree ??
I hope this has been instructional for you guys. I have a nice fire going in the old woodstove, and I need to feed the dog. An egg isn't enough. R :-[
Quote from: Rem on November 26, 2016, 03:21:40 PM
The real questions is: How do you get a banjo player out of a tree ??
You appear at the bottom of the tree with a chain saw. He will come down on his on.
Great reply, Jeff.
In ages past, this kinder and gentler form oof pursuasion was called "gunboat diplomacy". 8)
Ken
Quote from: jeffs55 on November 26, 2016, 03:42:46 PM
Quote from: Rem on November 26, 2016, 03:21:40 PM
The real questions is: How do you get a banjo player out of a tree ??
You appear at the bottom of the tree with a chain saw. He will come down on his on.
The proper response is "cut the rope". However, yours has merit. I suppose there is more than one way to disarm a banjo player. R ;)
]
The real questions is: How do you get a banjo player out of a tree ??
[/quote]
You appear at the bottom of the tree with a chain saw. He will come down on his on.
[/quote]
The proper response is "cut the rope". However, yours has merit. I suppose there is more than one way to disarm a banjo player. R ;)
[/quote]
Rem, I did not know that banjo playing was a "hanging offense" in the great white north. Took me about three seconds to understand your meaning. ??? I wore short pants and a T shirt yesterday. What did you wear?
Quote from: jeffs55 on November 27, 2016, 07:43:33 AM
Rem, I did not know that banjo playing was a "hanging offense" in the great white north. Took me about three seconds to understand your meaning. ??? I wore short pants and a T shirt yesterday. What did you wear?
Jeff ..... that's just sooooooooo wrong. Well, just so you know, I was walking around nekked last night outside. From the sauna to the house, at which point the sweat had frozen. Actually, we're having a very mild winter here. The coldest it's been was minus 20 (think -4 for you rogue temperature types). This morning, it's a scant -10 up at my place, -4 downtown (think 14 and 25 F, respectively). It could just as easily be -30 ish, so no complaints from me. I'm loving it.
Regarding the banjo .... yes, one strives to "stay in the closet" for as long as possible. Given the volume associated with your average banjo, it's a challenge. R ;)
Back to the original topic, here is another email from Dave Schweitzer:
Ken, the 8" is just a little slower that the larger one. Just mount the 180
grit on your Tormek and grind away either wet or dry, wet does give a little
better finish.
If you don't like it with in the first week just send it back.
As an update, I joined Wootz and took the plunge. I ordered a 180 grit straight eight inch diameter CBN wheel from D-Way. It will come with a steel 12mm bushing. I debated whether to order it for the T4 or T7. I finally opted for the smaller T4 size. It just felt like the right choice.
I will post my thoughts after using it. Coincidentally, I ordered three more 3/4" Irwin sharpening chisels.
So ends my Black Friday binge shopping. :)
Ken
Ref C.B.N.
On Knife grinding only. I currently use 2 different machines with interlocking spiral wheels. the faster machine uses C.B.N. 126
( that is the coursnes or grade ) The slower and smaller wheels use C.B.N. 107 Grade.
Both these wheels are no where near the size of the Tormek wheel.
They are as follows and in the respective order.
100mm diameter for C.B.N. 126
55mm diameter for C.B.N. 107
I have tried re-plating the larger wheel 100mm with the finer 107 C.B.N. but it just runs out more quickly.
I know there is a HUGE forum debate at the moment on C.B.N.
If you are only knife sharpening as I am, as a small business, please let me know the costs you are paying for RE-PLATING your wheels.That is, electroplating not resin .
I would like to know the costs for a Tormek T7 sized wheel in C.B.N. suitable for knife grinding at the speed of the T7 and the cost of re-plating there of.
Also of the Diamond type that is shown on the T2 and its replating there of.
Cheers.
Sorry, Bob.
I know nothing about the other machine(s). When my CBN wheel arrives, it will be the first time I have even seen one. i have no clue about replacing; in fact, I can't imagine me ever needing it with my home shop.
I think you need to contact a more specialized source for some high powered advice.
Ken
Ken - Cool! You got one. I'm really looking FW to your review! When do you take possession?
Bobl - How often do you have to have your wheels replated? How many knives between replating? Are you just sharpening or making knives? I'm curious because I don't have a CBN wheel and from what I've read that they have a very long MTBF, so long in fact that in most applications they may never need replacing or replating. Maybe I'm misreading what you are saying, but it sounds like you have to have it done quite often.
There is not really a debate here, but more a discussion because nobody has any experience with them. Any details about your experience would be appreciated!
Are you sharpening on high speed wheels? Any problems with heat? What do you think about the surface on the knife they produce? That kind of thing. "Interlocking spiral wheels". What machine uses that?
Grepper,
According to the post office tracker, it should arrive Friday. I will post my comments on using it.
Ken
Grepper,
The CBN wheel just arrived. A day ahead of schedule; I''m impressed!
Grandchildren's holiday concert at school is this evening. No time to try it today.
Ken
Not a problem Ken. All you have to do is give the school a quick call and tell them they are just going to have to delay the concert for a week. :)
Quote from: Ken S on December 01, 2016, 06:33:06 PM
Grepper,
The CBN wheel just arrived. A day ahead of schedule; I''m impressed!
Grandchildren's holiday concert at school is this evening. No time to try it today.
Ken
That would depend on how well they sing/play. :P ;D
Quote from: grepper on November 19, 2016, 11:35:17 PM
Due to the fact that the CBN wheels are machined, they should be concentric, balanced and true. ....... 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.
Mark (grepper),
I apologize for taking so long to answer. The fact of the matter is that I have not been able to find the "negative" I thought I remembered reading. As you mentioned somewhere, the cost has been the most negative I have been able to find. Following that would be the "loading up" of the wheel (chainsaw chain is known for its cleanliness due to pitch and gum). So far, I have not seen any concentricity issues mentioned.
The grinder is an Oregon 511a which is made by Tecomec in Italy. I will have to try verifying the concentricity of the flanges without the grinding wheel mounted.
I had a short chance to handle the CBN wheel today. I was concerned because the CBN is heavier than the SG-200. I thought the extra weight might be a problem for the motor. It turned out not to be an issue. I weighed both with the postal scale I use with my original Edgeonup tester.
The SG-200 weighed 2.448Kg (Weight is slightly reduced by some use and a couple truings.)
The D-Way steel CBN wheel (with steel 12mm reducing bushing) weighs 2.910 Kg.
The difference was not as much as I had thought. I planned to time the start up time needed to reach full velocity. Both were too quick to measure. I ruled "no problem".
I did not notice any difference in running noise between the two.
The machining of the wheel and bushing look quite good. The bushing fits nicely.
I am impressed so far and am looking forward to actually using the CBN wheel.
I believe the CBN wheel may work well with the planer jig. I don't think it will glaze with high speed steel, it will not need any depth compensation midway through. Someone else will have to verify that.
CBN wheels run coarser initially. I want to reshape a turning gouge. I had very good luck doing this with the Norton 3X wheels on the Tormek.I am curious to see how the CBN compares.
Most of my woodworking tools are older, high carbon steel. As such, I believe the SG will remain my general go to wheel.
I will keep you posted.
Ken
How much does the normally used stone, way weight?
Seems to me, if there were going to be an issue, it would most likely be with the plastic bushings on the shaft, over time.
Interesting observation, SADW.
This is the youtube which gave me concern about the weight of the wheel:
https://m.youtube.com/watch?v=CDNNEDjFcag
The T4 starts up with no hesitation with the CBN wheel. I had not thought about any issue with the nylon bushings.
The 250mm and 200mm wheel diameter Tormek models use the same nylon bushings. ( In fact, most of the parts are the same.) The shafts are the same diameter. The only shaft difference is the length, to compensate for the 10mm difference in grinding wheel thickness and the size of the motor/housing.
The SG-250 weighs about twice the weight of the SG-200 and substantially more than my eight inch CBN wheel. I will weigh my SG-250 and SB -250 after my family is awake.
I chose a simple flat wheel. There are radius wheels (1/4" or 6mm radius on each side). There are also "4 in 1" wheels with a larger area of the flat sides covered with CBN. The thicker metal core of these wheels adds weight. (My wheel has around a quarter inch of the flat side covered with CBN.) This is from woodturnerswonders.com :
"We don't have them for the T-4 but we can make them if we have a drawing. The T-7 wheel that is straight across with no material down the sides is about 5 pounds and the 4-1 design with 1 inch of material down the sides is about 10 pounds"
The other factor in weight is whether the wheel is steel (mine is) or 6061 "aircraft" aluminum. I am researching the practical differences, but do not have an answer at this point.
Some doubts have been raised about aligning the CBN wheel with the universal support. (The truings tool is not used with CBN.) The CBN wheels are turned on a lathe and balanced two different ways. I would be surprised if misalignment was a problem.
I hope to have time to use the new wheel this weekend. One of the first tests will be reshaping the half inch turning gouge I have on loan from Affinity Tool. It arrived with jig setting 2. I reshaped it to jig setting 4 and then back to 2 using the Norton 3X wheels (wet) on the Tormek. The 3X wheels did the reshaping in good time. I will see how the CBN wheel compares.The 3X wheels are 80 and 46 grit. I chose the 180 grit for my CBN wheel. There is an 80 grit option. I get the impression from Dave Sweitzer of D-Way that the two grits are largely interchangeable, with the 80 cutting a little faster and the 180 leaving a slightly smoother surface. I chose the slower, smoother path, at least for my first excursion. Incidentally, Dave also said using the wheel wet also leaves a slightly smoother finish. Unlike the Tormek wheels, these CBN wheels are single grit only.
I will post more after using the wheel.
Ken
For a grinding wheel not only the mass but also its angular mass (moment of inertia) about the rotational axes is important. Two wheels with the same mass can have significantly different moments of inertia.
The mass of the CBN wheel is often concentrated at its periphery and such a wheel behaves like a flywheel. It needs much more torque to reach the desired angular acceleration. It was probably Ken's subconscious reason to worry if the T4 motor spins the wheel. Congrats Ken, you have a good physical intuition. :)
A wheel on a bench grinder with 3450 rpm has kinetic energy more than 800 times larger than the same wheel rotating on the T4 with 120 rpm!
Jan
E=MC(3450) :)
Ken
ps Thanks for your compliment about my intuition. I will endeavor to live up to those expectations......
Last evening I finally had a chance to put CBN to steel.
First, I want to pay homage to Wootz for being the pioneer. I am following in his footsteps and benefitting from his experience.
My first test was reshaping a half inch turning gouge from jig setting 2 to jig setting 4. (I used the new SVD-186 jig on the T4.) This seemed a logical way to test the difference between wet and dry. The gouge has two wings. I ground the left side with the Tormek dry. My CBN wheel is 180 grit. I set a timer to give a rough idea of time passed. By the one minute mark the left side was reshaped. I was impressed. This wheel definitely cuts!
I filled the trough with just enough water to cover the edge of the grinding wheel. Using the same light touch as I did on the dry side, the wet wheel also completed the side reshaping handily in a minute. The cutting action seemed somewhat muffled by the water. The cut seemed ever so slightly smoother. The CBN wheel required no extra water for absorption. The only water spillage was from a little drippage from the turkey baster. I was convinced that for this operation, the CBN wheel could be used wet or dry.
For the second test, I used the same procedure I had used previously with the 3X wheels and the two Tormek wheels (SG and SB). I placed a 3/8" metal lathe tool bit in the SE-77 square edge and set the bevel angle to 30° with the Anglemaster. I then ground for a timed five minutes. The amount of grinding easily matched the 80 grit 3X wheel and was reasonably close to the 3X 46 grit.
I used the recommended lighter touch. For the record, the CBN wheel removed considerably more steel than the SG had removed earlier. In that earlier test, surprisingly, the SG surpassed the SB. I have since learned that the SB responds better to a light touch and plan to retest it.
I chose 180 grit instead of 80. For an active turner doing a lot of reshaping, the 80 grit wheel would be faster. The 180 leaves a surface like the SG graded coarse. My wheel is the flat model eight inch diameter. It is steel, although I have it on good authority that either steel or the aircraft grade aluminum work fine.
I think CBN may be what we need for planer blades. This may well require more than one wheel with different grits.
If I was limited to only one grinding wheel with my Tormek, it would be the SG. Based on this initial experience, assuming the wheel remains flat, I can see one or more CBN wheels as useful adjunct components.
I will post more after using it more.
Ken
Quote from: SharpenADullWitt on December 03, 2016, 05:23:28 AM
How much does the normally used stone, way weight?
Seems to me, if there were going to be an issue, it would most likely be with the plastic bushings on the shaft, over time.
SADW,
I weighed a fairly new SG-250. It weighs approximately 4.9 Kg, or twice the weight of the SG-200.
Incidentally, I started to reshape the turning gouge back to jig setting 2 with the SB-250 blackstone. It was cutting, but not nearly as well as the CBN. After ten minutes I suspended the operation. I have never had much luck with the SB. I keep thinking I am doing something wrong; I have not given up on it.
Ken
Wootz,
The last paragraph mentions that CBN wheels are often dressed with diamond tools. It might be worth exploring further.
http://www.grindingprocesssolutions.com/CBN/vitrified.html
Ken
Thank you for that, Ken.
Unfortunately, I don't believe this dressing is for electroplated CBN wheels.
As to my problem CBN wheel, the factory promised to send me a proper one, so the saga may end up with me having two wheels, the concaved and the rightly flat, for the price of one.
The only question is why would I need a defective wheel even for free?
But do you remember a discussion on middle overgrinding of long knives?
I noticed that longer knives sharpened on that concaved CBN wheel have less of this problem.
I wouldn't be able to foresee this advantage of the otherwise defective wheel, but post-factum it is easy to understand why it works it.
Cheers
Wootz,
I am glad you will end up with a proper wheel.
It goes against my thrifty nature, however, I would suggest you just recycle the defective wheel. Life is too short to clutter your mind and shop with tools which don't work.
Thanks for being the pioneer.
Ken
Quote from: wootz on December 05, 2016, 11:50:49 PM
The only question is why would I need a defective wheel even for free?
But do you remember a discussion on middle overgrinding of long knives?
I noticed that longer knives sharpened on that concaved CBN wheel have less of this problem.
I wouldn't be able to foresee this advantage of the otherwise defective wheel, but post-factum it is easy to understand why it works it.
Cheers
Every cloud has a silver lining. :) ;)
Jan
Wootz,
Don't throw away the saddled wheel. I have a use for it which needs your help.
Details to follow.........
Ken
I have run into a glitch with my idea of using my CBN wheel wet like a regular Tormek wheel.After the sharpening session I carefully dried the wheel and the steel reducing bushing. I wiped them with Starrett oil and hung the wheel. Last night I examined them for any rust. I found the slightest bit of rust on the 12mm bore of the reducing bushing. Also, while the wheel itself did not show any rust, the shallow drill holes made to balance the wheel showed definite light rust.
Based on my initial use, wet grinding seems to offer some advantages. It does trap the grinding dust in the water. It does offer some slight advantage with not heating the steel, however, due to the slow speed of the Tormek, that difference is minute. I also find the nuisance in using the water trough minimal. The rust problem is not minimal.
I will be exploring the options for reducing both sides of the "rust and dust" problem. I have a bottle of Honerite Gold on order. I will see if this water additive eliminates the rust problem (combined with good care). I will do this in two steps. The first step will be a relatively short sharpening session, typical of my work, and then careful storage. I will examine the wheel and bushing carefully for signs of rust.. If several short sessions are rust free, I will leave the wheel in solution for longer times with the motor running intermittently. This would simulate working conditions for a professional sharpener or turner.
I will also test the Honerite Gold with the SG to see if it prevents rust staining from imbedded steel particles, as asked by Jan.
On the dust side (from dry grinding), I will follow Tormek's path (as used in the T2) and rig up one or more magnets. Borrowing an idea from the T8, the removable magnet is a real convenience. The magnet holds the steel grindings. When the magnet is removed, the grindings are released. I will start with placing the magnet(s) in a plastic sandwich bag. Removing the magnet will release the grindings.
Related, I purchased the CBN wheel to use with the T4. Using it wet, I will try using it with the T8 to take advantage of the removable magnet. (The magnet on my T4 trough is attached with electrician's tape.)
I have searched unsuccessfully for related tests. The Honerite Gold online search results are all "at such and such a dealer", no test results. Incidentally, Honerite and Honerite Gold are different formulas. The gold is for water stones; the non gold is for oilstones. In the US, the product is sold under the Boratool label and imported by Affinity Tool (as is the Tormek). I contacted Affinity. They are not aware of any previous tests. However, they generously offered to send me a bittle of Honerite Gold for the tests.
Not all testing has the luxury of being done under strict scientific scrutiny by scientists in a lab. Sometimes we amateurs just have to do our own best guess basement workshop testing.
(Henry Ford first tested his gasoline engine in the kitchen. Needless to say, his wife was not happy that the noise awakened the baby!)
Ken
Quote from: wootz on December 05, 2016, 11:50:49 PM
As to my problem CBN wheel, the factory promised to send me a proper one, so the saga may end up with me having two wheels, the concaved and the rightly flat, for the price of one.
The only question is why would I need a defective wheel even for free?
The concave one could be used for anything with a convex edge, such as pruning shears, bypass loppers, pizza cutter wheels, etc. You can also use it for experimental work where you're afraid you might damage the good one.
My standard test for grinding wheel efficiency is to put a square metal lathe bit into the square edge jig (set at a 30° bevel) and grind for five minutes. I would be interested to see what happened if you did five or ten minutes on one of the high spots. You could measure the amount of concavity with feeler gages. If ten minutes made any difference, carry on. If the first high point wears down, work on the other end.
Ken
I described this procedure in my posts about testing the Norton 3X wheels.
Someone asked about the configuration of my CBN wheel. I chose a flat wheel, with no radaii. The two sides each have a narrow strip of CBN abrasive. My intentions are to use just the flat part of the wheel, just like the Tormek wheels.
Ken
I reran my standard five minute metal lathe bit with the now broken in CBN wheel. It now cuts like a 180 grit wheel. It cut well through the entire five minute test.
Dave Sweitzer of D-Way emailed me today that he has shipped me two ten inch CBN wheels for testing. I look forward to running more tests and will report the results. These wheels will also let me compare the T4 and T7/8 with CBN wheels.
Ken
Ken, I would be interested if some of the 10 inch CBN wheels you are testing would be suitable for flattening the back of chisels or plane irons. I am afraid that the side strip of CBN abrasive may be too narrow. ;)
Jan
Interesting question, Jan.
Let's look at plane blades first. David Charlesworth has devised a very clever solution. The only part of the back which needs to be pristine is the last small fraction of an inch or centimeter. David devised "the ruler trick" to polish just the end of the blade. In the link he demonstrates it.
https://m.youtube.com/watch?v=nykVPKbUGTo
Chisels are different. If the chisel back is convex, the chisel will not track properly. The English vernacular term for this convex back is having a "belly". The late Leonard Lee gave excellent advice for handling a new chisel with a belly: "return it to the dealer".
I have a favorite very old small Buck chisel which had a belly. I flattened the back using the side of my SG-250. It was a labor intensive process. :( In fact, my original motivation for buying a Tormek was when my hands hurt after preparing new chisels for a dovetail class.
Fortunately, most of the chisels I have worked on are either flat or (more commonly) have a concave back. With a concave back, I just polish the end.
This is leading up to a statement that for most users, I would not worry about whether the CBN wheel had grit on flat side. Mine has a small amount. This was supposedly added for carvers. I am not a carver; I am quite content with the basic flat surface. Other members may feel differently.
Ken
PS I will keep your question in mind when the two wheels arrive (hopefully Monday or Tuesday).
Ken, I like the David Charlesworth approach but it is only for blade with already flattened back. He describes a ruler trick how to remove a burr after sharpening the edge while blade back should be reasonably flat before the edge sharpening. ;)
Based on my experience the plane blades are often concave and you have to flatten circa 25 mm from the edge. Recently I was sharpening a 50 mm (2 ") plane iron with 59-60 HRC and I needed 15 minutes to flatten its back on the side of the SG stone graded coarse. It was a very difficult task. I had to de-clog the stone side several times during the flattening. I cannot imagine to do this flattening by hand using the waterstones.
My client was a violin maker, so his claims were quite high. He told me that after the blade flattening and sharpening the chips thickness dropped by one third. :)
Jan
Just a point.
A C.B.N. wheel should be run dry.
That is one of the benefits of C.B.N.
Dont use it as a whetting wheel. It is designed to be run dry.
Lets go from here.
What are your experiences on it dry.
Bo
The Knife Grinder
I agree that CBN wheels work very well dry. Initial tests indicate that they may also work well wet. My testing is still in progress. Until I feel that my testing is complete, I don't want to limit my options.
Ken
Quote from: Jan on December 18, 2016, 02:18:34 PM
Ken, I like the David Charlesworth approach but it is only for blade with already flattened back. He describes a ruler trick how to remove a burr after sharpening the edge while blade back should be reasonably flat before the edge sharpening. ;)
Based on my experience the plane blades are often concave and you have to flatten circa 25 mm from the edge. Recently I was sharpening a 50 mm (2 ") plane iron with 59-60 HRC and I needed 15 minutes to flatten its back on the side of the SG stone graded coarse. It was a very difficult task. I had to de-clog the stone side several times during the flattening. I cannot imagine to do this flattening by hand using the waterstones.
My client was a violin maker, so his claims were quite high. He told me that after the blade flattening and sharpening the chips thickness dropped by one third. :)
Jan
Jan,
Interesting point. My 1000 grit waterstone is now almost half size due to flattening too many backs. (So are my fingers. :-[ ) I don't recommend oilstones, either. I believe the key to success in flattening is to start with a coarse enough abrasive.
I spend several hours flattening a very hard oilstone using carborundum powder on a glass plate (with water). A steel plane blade might flatten more quickly. This method would be much more cost effective than a large coarse diamond stone or flat plate for occasional work.
How did you deglaze the side of your grinding wheel? The handbook is strangely silent about this, and it is a real issue.
Checking with a straight edge, I think it would be possible to use the round face of the grinding wheel to remove most of the high spots. The molding cutter jig works this way. If you were able to remove most of the metal this way, finishing on the side of the wheel or by other methods would not be so laborious.
Your effort has resulted in a substantial improvement in plane performance for the violinmaker. Bravo!
Ken
The cowardly, expensive option would be to purchase a new, hugh quality blade. These are thicker and surface ground at the factory. My less logical, emotional self would prefer to spend the time to correct the original blade.
Thanks for your response, Ken! :)
I do not have a suitable set of waterstones with different grits and I am not sure if I would have enough usage for it. For tools flattening I am using either a bench-mounted belt sander with 240 grit or the side of the SG stone.
The belt grinder works more quickly than the SG stone, but when the belt is worn out and hot it is often bulged in the middle of its width. The bulge causes that the blade back is not exactly flat, it is a tendency to concave it. That is why I prefer the grinding direction away from the edge, because the belt is pressed down before it reaches the sensitive area near the edge.
For unclogging the SG stone from embedded steel particles I simply use the coarse side of the Tormek stone grader. Quite high pressure is necessary for some 45 seconds. ;)
What concerns the mentioned violinmaker, he uses the plane to stitch the halves of the top and back plates. The top sound-table is made of soft tone wood – spruce while the rear part is from hardwood – maple. The plane iron was ground with a 28°edge angle.
The violinmaker is satisfied but may be applying the David Charlesworth approach would make him even more happy. :)
Jan
Jan,
I would not purchase a set of waterstones to flatten an occasional plane blade or chisel. I think the cost effective way is to get a piece of thick plate glass and some wet or dry sandpaper in varying grits. The sandpaper gets consumed, but the glass lives to sharpen another day.
My daughter plays the cello. I have enjoyed meeting several violinmakers over the years. I am pleased your efforts were successful.
Ken
Yes, Ken, I agree with you. During my pre-Tormek period I was using a flat and polished marmor (marble) plate and my own honing guide. Both worked fine. It had never occurred to me how excellent Swedish equipment I will have one day. :)
Jan
Jan,
I believe the real key ingredients in sharpening (as in life) are experience and imagination. While the Tormek is quite versatile, there are times when a flat plate is a useful supplement. The wise sharpener knows which tool to use for the job at hand.
The wise sharpener also knows the job requirements. A violinmaker making very thin, precise shavings, would want a more highly tuned plane than most users. He also might prefer to have the original blade made extremely sharp instead of purchasing a new, thicker after market blade. His preferred way to prevent blade chatter would be skill and sharpness.
Working with this man would be satisfying for a dedicated sharpener.
He found the right sharpener.
Ken
Looking at the photos in Wootz' original post, I am disturbed by the very small amount of thread holding area with the EZYlock nut. The saddle in the grinding face is a manufacturing defect, presumably from a "bad batch", which should be correctable at the factory. The lack of thread gripping is a design problem. Presumably this could be easily corrected by insetting the middle of the wheel, something I have seen only on Tormek wheels. What bothers me is that this problem was not discovered and corrected during design. It makes me think that the designers did not actually test it on a Tormek before placing it on the market.
The dealer seems supportive and honest. The basic product seems sound and useful. I hope the dealer will correct the saddle defect and redesign the wheels to thread correctly on a Tormek.
Incidentally, I mounted my King 600 grit wheel yesterday. The bore fit is very snug. Unlike with Tormek wheels, it is necessary to hold the leather honing wheel with one hand to prevent the shaft from moving. This is really not a problen. The slightly oversize diameter does fit in the water trough. The bore area is not inset, as in Tormek wheels. This makes any side of the wheel dressing more difficult, but would not effect using the face. The nut threads fully, due to the wheel being slightly thinner than the Tormek wheels.
Ken
I know this is an old post but thought I would mention that the saddle issue on the Tormek CBN wheels is a thing of the past. So is the ringing problem that some people experienced. Our two new style wheels - the Spartan which has a nylon center and our Tornado which is has 1 inch of grit down the sides also are dead flat. We no longer make or carry the style wheel that had saddle issues. Thanks. Ken Rizza - Wood Turners Wonders.
Ken,
Thanks for posting. Old posts often linger long after problems have been resolved. I'm glad the saddle issue was resolved.
(the other) Ken
Quote from: Ken Rizza on May 29, 2018, 03:42:15 AM
I know this is an old post but thought I would mention that the saddle issue on the Tormek CBN wheels is a thing of the past. So is the ringing problem that some people experienced. Our two new style wheels - the Spartan which has a nylon center and our Tornado which is has 1 inch of grit down the sides also are dead flat. We no longer make or carry the style wheel that had saddle issues. Thanks. Ken Rizza - Wood Turners Wonders.
True, just to confirm that, I use both the newer Spartan and Tornado and can't be happier. Excellent support from Ken Rizza at all times.
Quote from: Ken Rizza on May 29, 2018, 03:42:15 AM
I know this is an old post but thought I would mention that the saddle issue on the Tormek CBN wheels is a thing of the past. So is the ringing problem that some people experienced. Our two new style wheels - the Spartan which has a nylon center and our Tornado which is has 1 inch of grit down the sides also are dead flat. We no longer make or carry the style wheel that had saddle issues. Thanks. Ken Rizza - Wood Turners Wonders.
I ordered Spartan CBN wheel #200 in Jan, but it had the same problem. But I couldn't replace or refund it because I'm in South Korea. So I'm waiting for Tormek diamond wheel.
oouch !