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Bench Grinders

Discussion in 'GOOFS & BLUNDERS YOU SHOULD AVOID!' started by jbolt, Jul 15, 2017 at 5:12 PM.

  1. jbolt

    jbolt United States Active User H-M Supporter-Premium

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    Angry with myself today. I recently bought a new Jet 8" 1hp 3600 rpm bench grinder to augment my 7" 1800 rpm Baldor. In my haste to get it up and running I made my first mistake, I did not bolt the grinder to the bench. My second mistake was not ring testing the new Norton 3x grinding wheels before installing them. Apparently the 46 grit wheel was damaged and on spool-up it broke in half as it neared full speed. The wheel guard contained the wheel halves but with the sudden stop of the wheels all the stored energy had to go somewhere resulting in the 60 lb grinder jumping off the bench onto the concrete floor. Quit amazing to see. This resulted in breaking one of the cast iron tool rests, cracking the cast iron base and bending the mounting bracket for eye safety shield. Fortunately the motor shaft and cast wheel guards are undamaged. I powered up the grinder with the wheels off and then checked for shaft run out with a TDI. After that checked out okay I put the factory wheels back on and powered it up. So far so good. Hopefully the vendor will replace the damaged wheel.

    So secure your grinders and ring test the wheels before installing!

    20170715_124503.png
     
    MrFixIt, BGHansen, terrywerm and 6 others like this.
  2. f350ca

    f350ca Canada Active User Active Member

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  3. NCjeeper

    NCjeeper United States H-M Supporter - Premium Content H-M Supporter-Premium

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    Glad you didn't get hit by flying wheel parts.
     
  4. Charles Spencer

    Charles Spencer Active User H-M Supporter-Premium

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    I would contact the company that sold me the wheel or Norton's or both and explain what happened. Of course the wheel could have been damaged in shipping, but a good company would want to know that too. I'd be interested in seeing what they said and/or did.

    "So secure your grinders and ring test the wheels before installing!"

    Yes, absolutely.
     
    Last edited: Jul 16, 2017 at 9:44 AM
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  5. firestopper

    firestopper H-M Supporter - Premium Content H-M Supporter-Premium

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    Yikes!

    Glad your physically fine, sometimes our pride takes a hit but we're only humans. You posting this will surely help prevent someone else getting hurt.
    +3 always inspect and ring test.
    Probably could have been worse if the unit was secured. Even after a ring test, I stand to the opposite side of the replaced wheel when starting. Those HS shop safety films really made an impression on me, even after 39 years.
     
  6. dieselshadow

    dieselshadow United States Do you smell something? H-M Supporter-Premium

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    Ring test?
     
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  7. firestopper

    firestopper H-M Supporter - Premium Content H-M Supporter-Premium

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    A ring test is conducted by tapping the wheel gently with a light, nonmetallic implement, such as the handle of a screwdriver for light wheels or a wooden mallet for heavier wheels. The wheels should be “tapped” about 45 degrees on each side of the vertical centerline, and about 1 or 2 inches from the outer edge of the wheel. Rotate the wheel 45-degrees and repeat the test. An undamaged wheel will give a clear metallic tone/ring. If it is cracked, there will be a hollow, “dead” sound and you will not hear a clear “ring.” In this case do not use and throw out the wheel.
     
    Last edited: Jul 16, 2017 at 7:29 PM
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  8. jbolt

    jbolt United States Active User H-M Supporter-Premium

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    Well I still have enough sense to stand off to the side when starting up after changing a wheel. I guess I got complacent since I've never had a bad wheel from a quality manufacturer. Lesson learned.
     
  9. TomS

    TomS Active User H-M Supporter-Premium

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    All I can say is, WOW!! Glad you didn't get hurt.

    Tom S.
     
  10. jbolt

    jbolt United States Active User H-M Supporter-Premium

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    Good news is the vendor is replacing the wheel. No argument whatsoever so good on them. I will say this experience now has me seriously considering the CBN wheels.
     
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  11. Charles Spencer

    Charles Spencer Active User H-M Supporter-Premium

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  12. jbolt

    jbolt United States Active User H-M Supporter-Premium

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    Tools for Working Wood
     
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