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Thread: Serious Bowl turning injury

  1. #16
    Join Date
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    Atikokan, Rainy River district, Ontario
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    Quote Originally Posted by Stan Calow View Post
    Another non-Facebook user. Can someone summarize how this could have been prevented?
    Very easily, make sure there is/are NO splits in the wood and slow down the lathe speed, high speed is the danger that time and again strikes out and causes havoc even killing turners.

    It seems to be hard for turners to take a good look before starting an a piece of wood

    Here is a picture of a piece of wood that had pieces splitting off of it 3 times, and the turner was lucky to not get that against his noggin or he might not be turning still, you better have a close look at the wood you want to turn and not just go at it.

    3 times from the same piece.jpg


    Lynne Yamaguchi got nearly killed for the same reason, here is the picture of the piece that split off, where you can clearly see where the wood had a split and another one in there also.

    The split wood that nearly killed.jpg
    Last edited by Leo Van Der Loo; 05-27-2017 at 1:51 AM.
    Have fun and take care

  2. #17
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    Quote Originally Posted by Stan Calow View Post
    Another non-Facebook user. Can someone summarize how this could have been prevented?
    Turn with your cage down? I think I'm 1 of 2 persons that does use the cage. That being said, I almost never use it while sanding. Although, I sand 500 RPM or less. The other cage user is a friend of mine.

  3. #18
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    Nov 2007
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    Fort Pierce, Florida
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    Nova generally rates the expansion mode as stronger than compression. That said, the fact that the bowl split would make how it was held immaterial. Rotational speed and internal weakness of the wood are the apparent key factors. Hope he will be OK, that would appear to be a very serious injury with possible brain injury.
    Retired - when every day is Saturday (unless it's Sunday).

  4. #19
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    Jun 2016
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    Beaufort, SC
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    In regard to expansion or compression, I have had several pieces come off in the compression mode and maybe one off of the expansion in the recess. I have often wondered why so many use the compressed tenon when I have had problems with compression. I use a Super Nova 2 chuck with the 100MM jaws and the 75mm jaws.

  5. #20
    Quote Originally Posted by Thom Sturgill View Post
    Nova generally rates the expansion mode as stronger than compression....
    Whatever they might mean by that if it is an accurate quote, they can only specify the characters of their chucks and not the wood.

    I'm not very trusting of using a mortise grip on a piece of wood. A tenon is held on all sides by steel jaws. A mortise is held by steel jaws on just one side which is trying to pry the wood apart ... wood and air are the only things pushing back.
    Bill

  6. #21
    Ouch, I agree, impact required internal surgery more than likely. Hopefully he comes out all right.

    High RPMs and sanding, that works more against you, than for you.

  7. #22
    Join Date
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    Quote Originally Posted by Bill Boehme View Post
    Whatever they might mean by that if it is an accurate quote, they can only specify the characters of their chucks and not the wood.

    I'm not very trusting of using a mortise grip on a piece of wood. A tenon is held on all sides by steel jaws. A mortise is held by steel jaws on just one side which is trying to pry the wood apart ... wood and air are the only things pushing back.
    I do not agree with you on that Bill, all you do is relying on the strength of the wood in it’s bonding to itself, where some will separate easier than others.

    With a tenon it is this small stub you are squeezing and hope it will not be pried off of the rest of the bowl, it doesn’t matter how tight you can squeeze that stub, as that will stay right there if the bowl is pried away.

    With a recess you rely on the same, but with a much larger area to support the forces that are pulling on the hold of the jaws on the wood.

    Can you over tighten ?, yes of course, and I would say in both cases this can be done, you could start to split the wood by squeezing the stub as well as expand too hard on a weak wood or shape.

    I personally have turned a few thousand bowls, and the greater majority have a recess to hold the piece after they are rough turned initially, I do not remember a single time that I split a bowl by expansion, lost maybe one or two with the tenon separating of the piece, and I feel much safer holding the large bowls as well as the smaller ones with a proper recess, YMMV

    Of course this has nothing to do with this case IMO it is like usually going TOO fast, and very likely a compromised piece of wood.

    And as why someone is going to use high speed to sand is beyond me, a good way to heat up the wood and surface harden the wood, even starting small splits from the heat.
    Last edited by Leo Van Der Loo; 05-28-2017 at 12:45 PM.
    Have fun and take care

  8. #23
    The argument for 'which is stronger the tenon or recess' will go on for ever, kind of like the old Miller Beer commercial, "Less Filling/Tastes Great!" I have and will maintain that neither has any advantage as long as they are made properly. The only exception would be that I would never use a recess on end grain turnings.

    One major teaching failure with woodturning is not letting turners know how important standing out of the line of fire is.... Number 1 line of defense.

    robo hippy

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