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    Death by snapped steel prod

    jokum
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    Post by jokum on Wed Jan 02, 2013 11:12 am

    hello all
    It is a widespread "fact" that if your steelprod (bow, for those of us that are not american :-)) breaks or snaps while in use the two ends will sving round and harm (kill) you, now I wonder if anyone in here have any experience with this, any live footage, any calculations or arguments within the laws of physics?
    Looking forward to hear from you.
    Jokum
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    Post by Geezer on Wed Jan 02, 2013 2:12 pm

    Jokum: Geezer here. In my experience as a crossbow maker for 35 years, I have seen ONE metal prod broken, that actually injured the shooter. A pal made a lightweight (70lb.) draw aluminum-prod crossbow, made with a leather cover over the prod. Later he chose to remove the leather cover, by cutting loose the stitching along the back, and cutting it free just outside the bridle-block. In doing so, he scored the prod all the way 'round. Unlike steel, which requires a substantial notch for crack propogation, aluminum is more like glass... a little scratch across the 'back' will do the job. So Rick took his bow out back and shot it about three times. On the third draw, the prod broke one one side, the end whipped back and struck his hand. It drew blood, barely. He went in the house and applied a band-aid. We replaced the broken prod with a new one and he went on shooting his bow, but he was pretty jumpy about drawing it for a few days.
    That's the worst I know from personal experience. We've had several aluminum-alloy prods break over the years. To my knowledge, we haven't had anybody else hurt. That isn't to say it hasn't happened, but I haven't heard about it. I believe a few steel prods out of Alchem's first batches broke, but don't have any numbers. If there had been serious injuries, or deaths, I think I would have heard of them, but maybe not....
    Then again, I'm making fairly light-weight bows, nothing over 200 lb. as a rule, and all of those have used new, purpose-built prods. Recycled leaf-spring prods, or prods drawn close to the limits of their ability might make a different tale.
    I would recommend fitting a 'sicher' strap down the back of the prod on stronger bows as a matter of course. Geezer.
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    Post by fiddler49 on Thu Jan 10, 2013 2:17 am

    I read some where on this site an account of a guy being killed in Sweden when his car spring prod broke at a re-enactor type event. Since then all the cross bow prods at this event have to have a piece of belt leather tied to back of prod. This method was tested with steel prods pulled till they brake. Leather prevented prods flying towards shooter. cheers fiddler49
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    Post by ferdinand on Thu Jan 10, 2013 6:47 am

    Better safe than sorry! I'll back my prod with leather!
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    Post by Ivo on Thu Jan 10, 2013 8:58 pm



    Recommend you guys check out this guy's channel, some nice stuff there.

    Ivo



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    Post by ferdinand on Thu Jan 10, 2013 9:05 pm

    Ivo wrote:

    Recommend you guys check out this guy's channel, some nice stuff there.

    Ivo
    Verry nice looking!
    I'll keep this in mind!
    Thanks.
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    Post by Rizzar on Thu Jan 10, 2013 10:18 pm

    I can recommend this method, too.

    I used this safety strap method for the last 2 prods, and compared to leather it just doesn´t look like you are hiding something.
    Death by snapped steel prod 2013-010
    Besides he is a very helpful guy, we phoned with each other a couple of times. So if there is problem with the language in his videos, I can help out.

    Rizzar
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    Post by jokum on Fri Jan 11, 2013 5:00 am

    well it looks nice, but as I am making a copy of one of the early 16th century european crossbows (maximillian) it is not authentic with any kind of cord, which is why I am interested in knowing if anybody have any facts about this, if they have experienced a steelprod snapping or know of anyone who has, and when and if it does, how does it do it? does it swing back as people say, or is it just a myth?
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    Post by mac on Fri Jan 11, 2013 7:46 am

    Jokum,

    I wish we had more information on this as well. I have heard that "some American was killed by his untested leaf spring bow at a shoot in Germany..." , but its a third or fourth hand account. It all has the feeling of an "urban legend."

    I am sure that badly designed steel bows can break. I am confident that when they do, there is a great chance for personal injury. As to which way the pieces fly; it probably depends on where the failure occurs and at what point in the process the limbs disengage from the loops of the string. Even if the pieces do not fly back and strike the shooter, they will probably fly somewhere, perhaps striking someone else.

    Maybe one of you computer-modeling-guys would like to to try to simulate this....?

    I also wish we knew whether a jopf like the one in the video really helps or not. It would be a shame to install one only to find out that it was insufficient to its task.

    Mac

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