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Thread: Selecting CBN wheel.

  1. #1
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    Selecting CBN wheel.

    I want to buy one CBN wheel. I will use my other white aluminum oxide grinding wheels: a 120-grit wheel and a 60-grit wheel for shaping for now. I think I like the 1.5 inch wide and 220 grit CBN. Does anyone think this will be a good plan? Also, how do steel CBN wheels compare to aluminum wheels besides weight? Thanks so much. Roger Davis. SMWT see you all tomorrow nite.

  2. #2
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    Dec 2009
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    Pauline, South Carolina
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    Since you already have the coarser aluminum oxide wheels for shaping, I would recommend a CBN of 220 or even 350 for putting a new edge on when turning with out removing much metal.

  3. #3
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    Mar 2010
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    I recently attended a Stuart Batty 5 day course and he recommended a 350 grit CBN and that is the grade of stone I purchased

    see 30 minute into video link below

    https://www.youtube.com/watch?v=N7BjRcSDurM&t=3456s




  4. #4
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    Feb 2018
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    Cookeville TN
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    I just upgraded from a 180 CBN to 350. I like it a lot better. Like you I have a 120 grit Aluminum oxide on the other side for rough shapeing and sharpening carbon steel tools.

  5. #5
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    What I use

    Roger, some may depend on what and how you turn. I have 80, 180, and 600 grit CBN here and 1200 grit CBN on a slow-speed Tormek, plus another bench grinder with ALOX wheels. I sharpen my skews, larger bowl gouges, and scrapers on the 600 and my spindle gouges on the 1200.

    For me, the 600 is perfect since I strop the skews to a polished edge and hone the burr from the grinder from the scrapers then raise a working burr with a burnisher. If using scrapers directly from the grinder as some do, I'd want a coarser wheel for that.

    The 1200 grit is better for the spindle gouges since it's easier to polish the cutting edge. A polished edge can give a smoother surface on hard woods (little or no sanding needed) and I think it stays sharp longer than an edge straight off the grinder.

    I use the 80 grit only for reshaping tools, something your ALOX wheels will do. Since I have the other wheels I almost never use the 180 grit, but I might use it on larger bowl gouges if I turned a lot of big green bowls.

    One way to help decide might be to visit a turner or two and see how you like the speed of grinding and the edge from their CBN wheels. Be sure to try CBN wheels that are well used - all of them, even the very fine, are much more aggressive when new.

    JKJ

  6. #6
    I can remember when they were pretty much only 80 and 180 grit. I probably use the 180 most of the time now. I prefer the burr from the 180 on my scrapers for heavy roughing of bowls, and for most of my gouge work, which is mostly clean up and finish cuts. I did recently add a 320 grit, and am still experimenting with it. There was a recent article in the AAW magazine about wheels and sharpening which you may be able to find. In it Tom Wirsing says that he prefers the 600 grit wheel. So, in my opinion, the 80 grit isn't necessary, but I still like it for removal of stock, and minor profile changes. The 180, or 220 will do fine for about 90% of the cutting you will ever do. I am thinking, but haven't totally satisfied myself, that the 320 may be a bit fine for heavy roughing cuts. The 600 grit is fine fir really clean finish cuts on difficult woods that are soft or prone to tear out, but lousy for heavy roughing because the edge doesn't hold up as well. I am not a skew expert by any means, but the 600 grit seems to be fine for it, after a trip to the honing wheel on my Tormek. I saw Eric Loffstrom take his skew to a 60 grit wheel and then hand hone it on leather with honing compound, and then shave his arm. So, it will do.... If I need to get serious about reshaping a tool, like taking a new scraper blank from Thompson or D Way, and turning it into a NRS, I go to the 36 grit belt sander first, then the 80 grit wheel. I would suggest you keep the 60 grit wheel for any serious profile changes on your tools. I do have a 1000 grit CBN wheel, but don't use it much.

    robo hippy

  7. #7
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    Quote Originally Posted by Reed Gray View Post
    I do have a 1000 grit CBN wheel, but don't use it much.
    Is it an 8" wheel for a bench grinder? Do you plan to keep it? I'd like to try one for my skews.

  8. #8
    John, I am going to keep it for a while longer.... Ken Rizza said it was the first one he got, and we did some trading for it, rests for wheels..... The biggest problem with having different grinders and wheels is to get the platforms adjusted very precisely. Being off a tiny bit going from 80 to 600 or 1000 can make for a longer time sharpening. Even a tiny difference of 1/32 of an inch in the gap between wheel and platform can make a 1/2 degree difference in angles. Then, of course I set them up and then I take them off for transport to a demo.....

    robo hippy

  9. #9
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    Quote Originally Posted by Reed Gray View Post
    ...Then, of course I set them up and then I take them off for transport to a demo.....
    Do you take the grinder too? If so, can you mount both to a piece of plywood and take the whole thing? I mount each grinder+varigrind and tormek bases to a separate piece of 3/4" baltic birch plywood so I can move it if needed.

    Maybe some day when I'm not so cheap I'll get one of your rests to try! In the mean time, I make these to set the platforms:

    _scrapers_IMG_7811.jpg

    JKJ

  10. #10
    Maybe some day I will learn to take pictures and post them..... Need help from the kids... I don't like using other grinders, in part because of the difficulty of setting up platforms pretty exactly. I made boxes about 36h X 26l X 13 w, with a shelf in the middle. I can crate them up to ship to symposiums in a big crate with the grinder bolted to the shelf, or take it to an evening demo. The box acts as a table for a demo. For the Symposiums, I need 2 grinders, one for the two platforms I make. I had 3 grinders up in Portland because it was close. Each grinder is also bolted to a piece of plywood so it can be clamped to a table or bench, or when at home, screwed down to the bench. I would expect that with your jigs, you would most likely get the same half degree of variance that I get every time I set them up. Close works for the coarser wheels, not as well for the finer ones. At least in my experience.... Maybe some day they will be laser guided to set up at perfect matching angles.....

    robo hippy

  11. #11
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    Quote Originally Posted by Reed Gray View Post
    Maybe some day I will learn to take pictures and post them.....
    Sign up for JKJ's free on-line private personalized photo and posting seminar, offered only to select individuals, invitation only, applicable for this and the other forums.

    Yes, the platform angles are easy to get wrong, but those angles for which I make the plexiglas gauges are always right on. I can set for a 38-deg skew, for example, and the first light touch to the wheel matches the last time exactly. It is, however, some effort to make one for each angle. So far, I have them for two different skew angles, one for my favorite NRS grind, and one to get a perfect 90-deg edge on the card scrapers I use, harder than it might seem. This method was useless before CBN kept the wheels at a constant diameter. (Does your rest compensate for change in diameter for ALOX wheels or best used with CBN?) Tormek supplies a convoluted gauge for their stone wheel machines that I always found difficult to use and not very precise.

    Your fixed-angle platform sounds useful, for me as long as it could be used on the same grinder as the wolverine and Tormek supports.

    Old picture with old CBN wheel - I don't use the radiused edge wheels now.
    tormek_B.jpg

    JKJ

  12. #12
    Join Date
    Jul 2018
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    Knoxville,TN.
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    Thanks all.

    Quote Originally Posted by Roger M. Davis View Post
    I want to buy one CBN wheel. I will use my other white aluminum oxide grinding wheels: a 120-grit wheel and a 60-grit wheel for shaping for now. I think I like the 1.5 inch wide and 220 grit CBN. Does anyone think this will be a good plan? Also, how do steel CBN wheels compare to aluminum wheels besides weight? Thanks so much. Roger Davis. SMWT see you all tomorrow nite.
    Thanks all. Great information. Is steel better than aluminum CBN wheels?

  13. #13
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    Quote Originally Posted by Roger M. Davis View Post
    ... Is steel better than aluminum CBN wheels?
    Opinions vary. I've only used aluminum so I can't compare based on experience. Both have the grit electroplated in the same way. Some say aluminum wheels cut cooler since heat transfer in aluminum is higher. I'm not sure that would make a significant difference in use since heat in the tool is generated by the friction, not by heat transfer. Steel can rust if exposed to water, such as using one in a Tormek water bath and not drying it afterwards. Aluminum can corrode. Steel can be a LOT heavier: a few people have reported slow startup speed on an under-powered bench grinder or having to give a boost by hand on a grinder with two heavy steel wheels.

    JKJ

  14. #14
    I don't know that there is any difference. There were questions about the electroplating being different for aluminum and steel, but no one has seemed to have problems with the aluminum. Ken Rizza did have some plastic/polymer type hubs as well. The half horse Rikon grinder is a bit under powered for running 2 wheels. Some 3/4 hp grinders are the sane way. I do prefer more heavy duty tools...

    robo hippy

  15. #15
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    Quote Originally Posted by Reed Gray View Post
    ... Ken Rizza did have some plastic/polymer type hubs as well.
    I think he said the problem with those (nylon?) was balancing when used at bench grinder speeds, the Tormek version is fine. His aluminum wheels are perfect.

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