Grinding wheel problem

Discussion in 'Woodturning Discussion Forum' started by Yonatan Court, Nov 1, 2017.

  1. Yonatan Court

    Yonatan Court

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    I had an accident with my grinder, the tool slipped off and got stuck between the housing and the wheel, damaging (taking small chunks from the edges on both sides) the wheel in a couple of places. Now the wheel has some high points that cause the tool that I am sharpening to bounce which makes it hard to sharpen. I have tried a couple of times to remove the high spots with my diamond wheel dresser to no avail. Any suggestions or do I get a new wheel.
     
  2. Bill Blasic

    Bill Blasic

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    Get a new wheel!
     
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  3. Doug Rasmussen

    Doug Rasmussen

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    Assuming based on the experience you're relating, the diamond dresser is being hand held. You need some sort of rigid guide for the dresser, hand holding won't do it.

    As to the wheel having high spots, that doesn't sound good. Chipping on the edge of a wheel shouldn't cause high spots on a grinding wheel. Worst case you may have bent the grinder's arbor. Does the grinder vibrate since the wheel chipping? There is a possibility the grinder is vibrating due to an out of balance wheel giving the impression of high spots.

    Take the wheel off and verify whether the arbor is bent. If so, get a new grinder. Otherwise try another wheel.
     
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  4. Bernie Hrytzak

    Bernie Hrytzak

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    The wheel should be discarded for safety reasons since the it could have micro-cracks now and could explode on you.
     
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  5. odie

    odie

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    Now is the time to get a dial indicator, if you don't already have one. checking for bent arbor only a couple thousands off will be a problem you won't overcome.

    I have the standard dial indicator and magnetic base, but as I searched HF for a picture, I ran across this one.....a, new item I think. Pretty cool, as long as that adjustable neck is nice and rigid:

    [​IMG]
    https://www.harborfreight.com/catal...eatured+Weight,f,Sale+Rank,f&q=dial+indicator

    -----odie-----
     
  6. john lucas

    john lucas

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    Been there done that. obviously the first thing is to be more careful when grinding. You need a fixed diamond truing system of some kind. ONeway sells one. If you take one of the T shaped diamond cutters and put it on your tool rest and take very light cuts you can true it up but it's so much better with a good system. Don Geiger sells what I use. http://www.geigerssolutions.com/Tru-N-Dress-Grand-Slam.html
     
  7. hockenbery

    hockenbery AAW Advisor Staff Member

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    I would get a new wheel. A damaged wheel can come apart,.
    At a minimum take the wheel,off the grinder a tap it with the plastic handle of a screw driver on the flat edge all around the each side. Each tap should make a ring sound from the wheel. A dull sound is a crack discard the wheel. This should be done with any new wheel too as they can be damaged in shipping.

    Dressing a wheel to round is easiest with a tool that has a controlled depth and a diamond point.
    don Geiger has a nice one.

    With practice you can do it with a hand held. Don’t start the dresser at 90 degrees it will just bounce and follow the out of roundness you want to get rid of.
    Start on the edge with the dresser at a 45-30 degree angle take very light strokes toward the center of the wheel.
    Don’t let the tool bounce or ride in on the low spots.
    Once the outside edge is round shift the tool a few degrees towards 90 degrees and widen the smooth part.
    Use the smooth edge as a guide and keep dressing into rough parts edge making it smooth.
    Keep taking strokes from the smooth to the rough trying not to remove material from the smooth part. Eventually you get the dresser to 90 degrees working across the whole surface of the wheel smoothly with no bounce.
    You now have the wheel true round and dressed.
     
    Last edited: Nov 1, 2017
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  8. John Torchick

    John Torchick

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    New wheel- why take a chance on the wheel exploding as stated. Cheaper than an emergency room. odie, that is an interesting picture- a dial indicator with a new Alabama socket wrench. :p Remember, I'm from Tennessee. ;) We have a football team.....sometimes.
     
  9. john lucas

    john lucas

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    John You mean our football team actually comes out to play sometimes. :) I made a homemade version of the Gieger wheel dresser out of a single point diamond, some all thread rod and plastic decking. I'll try to find a photo of it. It rides on the oneway tool rest and can be micro adjusted so it takes a little at a time off your wheel.
     
  10. Bill Boehme

    Bill Boehme Administrator Staff Member

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    I agree! Get a new wheel. Might as well get a CBN wheel and save yourself the time, trouble, and expense of balancing a matrix wheel.

    I'm glad you cleared things up about Odie's picture. My hasty and careless first look led me to mistake it for an Aggie socket wrench, but on second look I see that it has too many moving parts (more than one) to be used by an Aggie. :D
     
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  11. Toss the damaged wheel far into the darkness of the night. Buy a new one. Consider an upgrade to CBN wheel. You'll love it. - John
     
  12. charlie knighton

    charlie knighton

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    That thingy looks like an upgrade on the chewing gum and duck tape those hurricanes use .....see hokies vs hurricanes sat night on abc.....
    Buy new wheel
     
  13. Curtis Fuller

    Curtis Fuller

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    Could possibly have damaged the bushing in the wheel when all the grabbing and grinding was happening. Even if the wheel only suffered a few dings that could be dressed out the wheel would still be untrue from a damaged bushing. You didn't mention what kind of wheel but many have plastic bushings that can be replaced. But if you've tried that already then I agree with the others that it's time for a new wheel. Not worth the risk of having a wheel come apart or the frustration of trying to sharpen on a hit and miss wheel.
     
  14. olaf Vogel

    olaf Vogel

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    If you drop the wheel on the ground - sure.
    But knocking a chip off - not really. But it will be unbalances.

    All my wheels are scratch & dent - with chips. Took a dresser to them to get the chips out and then kept using them.
    Many years later - no issues.

    There's lots of concerns on the web about wheels "exploding", but I've never heard (or seen a post) of it actually happening to anyone.
     
  15. john lucas

    john lucas

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    Oh it has happened and there have been reports. It happened in our University metal shop. A big 10" wheel at 3450rpm. Scared the living daylights out of all of us and made believers out of us. It happened so fast the guy that standing at the machine just stood there. It was over before he could even move. Fortunately he was standing to the side and the guards captured most of the pieces.
     
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  16. Bill Boehme

    Bill Boehme Administrator Staff Member

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    Knowledge doesn't get any more first hand than that. :eek:

    Thanks for sharing.
     
  17. John Torchick

    John Torchick

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    Famous saying, "It won't happen to me."
     
  18. olaf Vogel

    olaf Vogel

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    To which I would say: 3450 rpm is WAY too fast for a 10" wheel. The centrifugal forces become huge.

    Read post #7 of here
    http://www.practicalmachinist.com/vb/general/bench-grinders-1750-vs-3600-rpms-215968/

    The other issue with schools / colleges etc, is that you get users who are not well educated around the tools. Either in specific usage or general practice.

    I.e. not really paying attention, then possibly jamming the tool into the wheel.
    I agree, that if used improperly, a user can destroy just about any well designed tool.
     
    Last edited: Nov 4, 2017
  19. robo hippy

    robo hippy

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    I did see a picture in a woodworking magazine once where a guy had about a 1/4 section of a grinding wheel stuck in his forehead. Not pretty. An emergency room friend also told some stories and commented that it was far more frequent than most think...

    robo hippy
     
  20. RichColvin

    RichColvin

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