Compouond Crossbow

Discussion in 'Zombie / Prepping related stuff' started by BrPio, Oct 15, 2013.

  1. BrPio

    BrPio .

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    Well this project seemed to evolve from another project. I was going to make a Chinese repeating crossbow, but I ended up scrapping that plan and here's why . I started first by making a bow. I used high carbon steel spring tempered. But it was extremely hard to draw, I had to stand on it to draw it . So I thought if I add a pulley system it would make a better compound bow for a powerful single shot crossbow (which I'v never attempted to build a compound xbow before). I found some high strength brass ball bearing pulleys where I live for only .25 USD, I purchased all they had for 3.50,. Made some steel mounts for the pulleys. I used paracord for the drawstring.
     
    Last edited: Oct 17, 2013
  2. kineticweaponry

    kineticweaponry Senior Member

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  3. xXdoomXx

    xXdoomXx Junior threadjacker ag. J

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  4. Ghosth

    Ghosth Over the hill but still swinging!

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    A regular bow compound made sense, let you up the draw weight, while being able to draw smoothly. And the let off let you hold it easily for much longer.

    But!

    In a crossbow, where the string is held until you pull the trigger neither of these really come into play.
    If you can't draw it wouldn't you be better off using a winch or mechanical linkage to draw?

    And with round pulleys not cams, there is no "let off" like a true compound bow. And it is being held by a mechanical device anyway, so what is the point?

    I see a show with a compound crossbow in it and laugh. (Revolution, etc)

    Now I could be totally wrong, but I just don't see the point.
     
    Last edited: Oct 16, 2013
  5. Slagskimmer Mike

    Slagskimmer Mike thinks TBG smells better than roses

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    The best reason I can think of to have compound on a x-bow is to have a light weight on the trigger mechanism. Instead of having a long trigger, a normal length trigger can have a normal pull weight.

    I think it will reduce friction at the point where the cord slips over at firing. This should make everything last longer/require less strength of the parts.

    Another reason might be to reduce the width of the entire weapon, making it much better in urban surroundings and close quarters.

    Just my guesses--cant wait to see more developments. It looks great so far.
     
  6. also compound bows achieve longer draw lengths with a much more compact limb so they are smaller. also they look cool!
     
  7. BrPio

    BrPio .

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    Thanks all for the feedback. Mike, You stated, less width, yes. That was what I liked and was going for. This bow has half the width and double the draw length of regular bows it's size.
    and Ghosth, even without the cams the total draw weight is reduced when using a pulley system and the draw length is increased (basic pulley physics). That was the point. A wench system would be to slow for what I have in mind, also it would make the unit more bulky.
     
  8. BeMahoney

    BeMahoney Builder of things

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    Is there a noisy ghost around?

    Hey ghost!

    Your point has an aspect which is right:
    A compound bow (as far as I got it right) will act with
    an increasing acceleration (in its limits), although it
    is SLOWER than a simple string, for the latter will have to move less string in length.. (completely disregarding drawweight, which is also ok in one point: the trigger holds it while waiting/aiming..)

    The other thing is how that is communicated,
    combined with the fact that learning sth. works
    best when having fun with that..

    Regarding that your word might be called "pointless"
    so to say. - BrPio feels bad and might not even have understood what
    you were really about..
    And you misread his words of re-using an older projects part!!!- which is perfect to me.

    Learning (what we are all here for?) is literally "getting a grip" on things..
    So how could ever experimenting be the wrong thing to do????

    To be honest, Jörg, the architect of this place established one single rule.
    And this rule makes one point: in a polite atmosphere learning can always
    take place.- And this might be crucial dealing with potentially harmful
    contraptions...????

    So if anone sees a point, he is always asked to communicate that friendly,
    for that´s the only way it will ever make sense.

    We´re here ´cause it´s fun isn´t it?

    Be
     
  9. BeMahoney

    BeMahoney Builder of things

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    @ BrPio

    "I see a show with a compound crossbow in it and laugh. (Revolution, etc)"

    I am not sure ghost says this here is a show!?- could it be he was talking
    about some movie or TV-show?

    (Just to prevent potential complete misunderstandingone-another?)

    Be
     
  10. Ghosth

    Ghosth Over the hill but still swinging!

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    Ok, I communicated poorly here, for that I am truly sorry.

    BrPio, I am NOT that creep. I truly do/did not understand the point of putting pulleys on a crossbow.
    It seemed totally useless, tits on a boar hog.

    That is not to say I was trying to devalue what you did. Just trying to understand "WHY" you did it!

    Please do NOT go away on my count.
     
  11. Withak

    Withak aka Whitehawk!

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    I agree BrPio, I enjoy seeing your creations and would hate to see that stop. I know myself sometimes I've written things that, in my head, sounded correct, but were taken wrong by others. I think the difference with TOHSNBN is that he kept doing it over and over again. I would invite you to continue to post and invite others to at least read their own posts twice and ask "how does that sound?" before they press 'submit'. Remember, in writing, we lose the benefit of tone of voice and body language, both of which are so critical to proper expression of emotion. Using written words only can certainly lead to unintentional misunderstanding. Stick around BrPio.
     
  12. pelleteer

    pelleteer Middle Aged Delinquent

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    Nooooo! :eek::( Pio, I hope you'll reconsider and continue posting. Maybe you just need to take a little time off and come back fresh at a later date. :cool: