Why CBN, or other coated steel wheels are not as good as a a matrix grind wheel......

Discussion in 'Woodturning Discussion Forum' started by odie, Apr 19, 2014.

  1. robo hippy

    robo hippy

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    One point I make when sharpening, about once a year, you will hear about some one who picks a use lathe and all the accessories for a steal price. It is sold because 'it just wasn't fun any more'. The new owner takes it home and sets every thing up, and makes the startling discovery that the tools were dull. Nothing more....

    robo hippy
     
  2. Mark Mandell

    Mark Mandell

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    You can, of course, pay larger for a belt sharpening "system" from turning suppliers, but the $130 Ricon combination 1x30" belt and 6" disk sander at Klingspor will do just fine with belts made for sharpening alloy steels in grits up to 400 for $2 a piece. Difference will be that you'll need to make a few jigs to fit.
     
  3. hockenbery

    hockenbery AAW Advisor Staff Member

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    I agree with Reed 100% On this. Sharp tools used properly and there is no effort required by the turner.

    If you feel any stress on the tool handle or are getting bounced around or beat up when roughing you don't have sharp tools and good technique.

    If you have good posture, sharp tools, and proper technique you can get tired but nothing will hurt.

    Al
     
  4. hockenbery

    hockenbery AAW Advisor Staff Member

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    We had two kids 12-13 in a turning class that met Saturday mornings for 5 weeks.
    About the 3rd class Johnny and Warren came in. They had visited one of their grandfathers who let them use his lathe.
    Their one comment - " boy were his tools dull".........

    Al
     
  5. Bill Boehme

    Bill Boehme Administrator Staff Member

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    What a tragedy. On another forum someone asked where other turners sent their tools to be sharpened. :rolleyes:
     
  6. robo hippy

    robo hippy

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    Al and Bill, Yup! and Yup!

    The finish cut because no one likes to sand. One, tools must be sharp. Two, present the tool to the wood so that it cuts cleanly and you don't get catches. Three, move with the tool so you get an even no bumps and humps surface.

    robo hippy
     
  7. Mark Hepburn

    Mark Hepburn

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    I can just see this as a Seinfeld episode:

    Kramer: "yeah, just got my tools back from my grinder guy."

    George: "grinder guy?! grinder guy!? whaddaya mean a grinder guy?"

    Kramer: "Oh yeah, I've got a grinder guy. You gotta have a grinder guy."

    George: "C'mon Kramer!! Jerry, tell Kramer he can't possibly need a grinder guy!"

    Jerry: "Why not?"

    George: (murmuring) "I gotta get a grinder guy".

    :)
     
  8. Bill Boehme

    Bill Boehme Administrator Staff Member

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    Not that there's anything wrong with that. :rolleyes:
     
  9. Mark Hepburn

    Mark Hepburn

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    :D

    (By the way, Bill, where do we send our tools to get sharpened?)
     
  10. odie

    odie

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    Yep, I'm enjoying this immensely!

    I've long ago come to the point where I give my point of view, and allow others to have theirs. I'll even, at times, argue my point........but, the bottom line is: I understand that everyone has their own individuality, and my opinions are based on things others don't see as I do.....and vise-versa!
     
  11. n7bsn

    n7bsn

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    True story

    Dave (owner of D-Way) has had customers ask him if they can send the tools back to be resharpened and asked about buying "several" so they can cycle them back to him for sharpening.
     
  12. Duane Meadows

    Duane Meadows

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    Hmm... business opportunity? Not so much, the other two turners in this area probably sharpen their own! Of course there is always UPS.:)
     
  13. Rich Aldrich

    Rich Aldrich

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    I actually had a catch while grinding a bowl gouge - all due to inexperience - talk about pucker factor. Using a Vari-grind I, the tool slipped off the side of the wheel. It was a Norton blue 80 grit. The grinder was almost stopped and as soon as the gouge was removed from binding the wheel, the grinder started trying to get to speed. I was quick on the shut off but in shock. After replacing the wheel, I then tried one of the contained jigs and didn't like it.

    This was my reason for going to a CBN. It is a bit safer if you aren't as talented at sharpening. The wheel is not going to be damaged if you have a catch. That is what I have now along with the Vari-grind I. I can now grind my tools without the worry of having another catch at the grinder and possibly getting injured. Again, it is due to bad grinding skills. I bought it for my own safety due to poor sharpening skills.

    I think if my tools didn't have such long handles, they would be easier to control and get the feel of grinding the tool. Removable handles would probably be better for me only due to sharpening. I don't have much of a turning muscle yet, so I try to make up for that with a long handle on my tools. :D

    I have tried honing, but haven't mastered it yet.

    Recently, Doug Thompson released You Tube video on sharpening that was most helpful to me.
     
    Last edited: Apr 24, 2014
  14. Jeff Deutschle

    Jeff Deutschle

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    I am not so sure about that. I have found that the burr will stay on quite a while, like until it is dull. Of course it depends on how big the burr is to start with.

    What are others experiences with the burr left on from the wheel? Does it wear off as soon as you start turning or not?
     
  15. odie

    odie

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    Jeff.......I think it also depends on how thick the burr is. A scraper will have a burr that is thicker at the base than a gouge. The angle of the grind will have a lot to do with it. I can see how this could vary, depending on the turners own techniques. Previously, I mentioned that if a burr does break, it will be a broken edge that remains. Honing makes all this irrelevant, but the formation of the burr on scrapers is critical to how well it will perform.

    ooc
     
  16. Duane Meadows

    Duane Meadows

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    Jeff, I don,t hone after grinding. Sometimes between grindings. Haven't had any problems that way.
     
  17. Jeff Deutschle

    Jeff Deutschle

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    Thanks for the reply, Duane.

    Just to be clear, maybe there isn't a "problem" having a little burr left. It might be the benefit that those that prefer a "serrated" edge from off the grinder get. But what I am wondering is if it just gets worn off as soon as you start to turn, as some seem to say. I have noticed that it stays for a while, and the turning works better when it is gone.
     
  18. Mark Mandell

    Mark Mandell

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    Speaking of Burrs

    My experience has been that grinder-made burrs are more fragile and short-lived than they are useful. I much prefer to sharpen the scraper, lap the grinder burr off, and then use a burnisher such as the Lee Valley tool http://www.leevalley.com/US/wood/page.aspx?p=20266&cat=1,330,49233 to raise get a strong and uniform burr.
     
  19. Jeff Deutschle

    Jeff Deutschle

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    But does the burr either break or wear off? Good or bad, I think it might not.
     
  20. robo hippy

    robo hippy

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    The burrs on a scraper, especially from the CBN wheels are very sturdy. I can rough out a 14 inch bowl with one no problem, and the burr is still left. I don't take the time to burnish a burr because there is little to no improvement in quality or durability. This is with both the M2 HSS, V 10, and the M4 what-ever that D Way uses. You can hand burnish a burr on your scrapers. I use a triangle burnishing tool. I looked at the Lee Valley burnishing tool, and didn't go for it. I have seen some use it, and they use a lot of pressure. You can over burnish to the point where the burr curls over which does make it difficult to cut with.

    With gouge burrs, if you sharpen, which means just a gentle kiss on the grinder wheel, you don't get much of a burr. If you grind, using a lot of pressure, you can get a fairly heavy and coarse burr. I found when I did that, I needed to hone the burr off in order to do a shear scrape. It would still do fine for heavy roughing.

    Again, the quality and strength of the burr depend on the wheel and how much pressure you are using.

    robo hippy
     

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