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Thread: Hollow grind with cbn wheel on low speed grinder- how far do you go?

  1. #16
    Wood Turners Wonders. Not cheap, but like you, I prefer the flat surface for plane blade grinding. I also work with a drawknife and find sharpening on the ws disc easier than other methods.

  2. #17
    Join Date
    Jan 2019
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    Fairbanks AK
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    I have upgraded relatively recently from standard grey 80 grit wheel to a Norton white 40 grit wheel, on a 6 inch grinder. I should have done that years ago and look forward to dropping the coin on CBN someday when that is my biggest problem.

    At my shop the eye shield on the grinder is carefully adjusted to square to the wheel. I free hand the irons on my grinder, to within about 1/16 inch of the edge when I do grind. I do still use a honing guide on my stones- which should and seems to does correct free hand errors on the grinder. When an iron gets to be a pain to hone on the stones with the guide, back to the grinder.

    In my experience the grinder takes off metal, but it does so away from the edge and saves me time on the honing stones. So yes, the grinder removes metal. But no, it does not shorten the life of my iron, but hollow grinding does reduce the amount of time I spend on the stones. At my place it is honing the edge that shortens the iron. Taking some metal out of the middle does not shorten the iron, but it does shorten the time I spend on the stones.

    If you just can't see it, drop a relative few dollars on a white 40 grit wheel and see for yourself before you drop real money on CBN.

  3. #18
    The gray wheels are practically worthless for grinding tools efficiently. The difference between them and the white wheels is less than that between white wheels and cbn. A 6 white wheel is about $25 while a 6" cbn from Lee Valley is $99. The cbn works better and I am confident it will outlast 4 of the white wheels.

  4. #19
    While not on topic, I will add that for me that the two reasons I prefer cbn over white wheels are that the wheel diameter does not change and that they tend to run more true which means they never have to be balanced or manipulated.

  5. #20
    Join Date
    Feb 2021
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    Israel
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    Thanks everyone. To be honest a lot of my tools and techniques are adapted based off of Dereks advise. It's his setup that I wasn't to emulate. I also think he wrote in his site that you can use most steels on cbn, not just hss. When the setup arrives I'll take your advise to heart. Sharpen using water until I can feel a wire edge. I'm planning on ordering a tormek jig for blade holding.

  6. #21
    Join Date
    Nov 2009
    Location
    Peoria, IL
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    I have to disagree. Been grinding to the edge for about 40 years. What you don't do is ignore dressing a grinding wheel to expose fresh abrasive, and you don't put more than the weight of the steel down on the grinding wheel. The caveat I would suggest for the CBN wheel is that if your steel isn't hard enough, you will foul the wheel with bits of carbon steel stuck between the abrasive particles.
    Last edited by Richard Coers; 05-13-2022 at 12:04 AM.

  7. #22
    Join Date
    Feb 2004
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    Perth, Australia
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    Quote Originally Posted by Richard Coers View Post
    I have to disagree. Been grinding to the edge for about 40 years. What you don't do is ignore dressing a grinding wheel to expose fresh abrasive, and you don't put more than the weight of the steel down on the grinding wheel. The caveat I would suggest for the CBN wheel is that if your steel isn't hard enough, you will foul the wheel with bits of carbon steel stuck between the abrasive particles.
    CBN is safe to grind all steel, except mild steel or unhardened/annealed steel. If the grit does become clogged (by grinding these soft metals), then grind hard steel to clear it.

    Regards from Perth

    Derek

  8. #23
    Join Date
    Mar 2019
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    Los Angeles, California
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    Grind until I see a nice strip maybe a 16th across the iron or chisel and it is sort of sharp, which usually means a burr on the other side. I stop at that point and move to diamond stones. I don't use the grinder much, as most sharpening is best done on the diamond stones. I was taught the Paul Sellers method in Waco, where he taught in the early 2000s, although when I took the class a few years ago, they emulate all his methods.
    Regards,

    Tom

  9. #24
    Quote Originally Posted by Prashun Patel View Post
    Mike. Btw, they make cbn discs for the worksharp. Even better than the diamond lap discs .
    Ah, I did find those CBN wheels for the WorkSharp - $50/each. I'll probably keep using the diamond ones I have for a while. Maybe when they wear out I'll spring for the CBN.

    Mike
    Go into the world and do well. But more importantly, go into the world and do good.

  10. #25
    Join Date
    Feb 2007
    Location
    South Dakota
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    1,625
    Mike, where did you find the CBN disks? I looked a bit but only found them in one place at $59
    The Plane Anarchist

  11. #26
    Wood Turners Wonders

    They make 3 double-sided discs (I have them all)

    80/150, 360/600, 800/1200.

    One could argue that if you finish on stones, you really only need the lowest one.

    The 360 and 600 though are aggressive enough that you could argue that a 360 cbn works like an 80 grit friable wheel, so you may only want to get the middle grit.

    I work my drawknives on the worksharp, though (an undiscovered secret) so, the higher grit polish is appreciated for me. Also, I have found the cheaper diamond lap discs north of 1000 grit to be useless and to breakdown and scratch very quickly. The cbn appears more durable so far.

  12. #27
    Join Date
    Feb 2007
    Location
    South Dakota
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    1,625
    thanks I just ordered a set of three.
    The Plane Anarchist

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