Crossbows - Everything about Building, Modding, and Using your Crossbow Gear

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» Question regarding the goat’s foot lever
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» Just finished my windlass crossbow!
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» Linen or Hemp String
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» Length of End Loops for Prod String?
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» Nut Diagram
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by banuvatt Fri Nov 01, 2019 3:16 pm

» Roller Nut Size
by banuvatt Thu Oct 31, 2019 7:59 pm

» anyone know anything about this one - updated with new image
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» Laminating crossbow limbs
by banuvatt Mon Oct 28, 2019 4:33 pm

» Info required for old laminated limbs
by banuvatt Sat Oct 26, 2019 5:48 am


    Semi Ballista

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    Post by hullutiedemies on Wed Dec 05, 2012 10:07 am

    Here is an easy and economical way to build a torsion engine
    Semi Ballista Veijo02_195
    Semi Ballista Veijo05_212
    Semi Ballista Veijo03_167

    Just tie two short skeins of cable
    Stick one end of a frame bar and throwing arm through the loop of the skein.
    Twist both arms one turn and string

    This thing pulls about 40#/7"
    It puts an airsof pellet into a card board box
    and a .17 BB through the box.


    Torsion spring here is manilla rope.
    1 gram of manilla can take 2 Joule load before failing - about as good as rubber band.
    About as goot as biomaterial goes.

    Other cable materials can of course be used.
    I have tested this system eg. with old woolen socks.
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    Post by Ivo on Wed Dec 05, 2012 1:54 pm

    I have tested this system eg. with old woolen socks.

    Semi Ballista 576186 Semi Ballista 576186 Semi Ballista 576186

    Not sure if you were going for laughs there, but you certainly succeeded and then some...

    This little ballista is actually really cool...three sticks, two socks, a shoe lace or the like for the string....damn, that's good stuff, haha!

    I've been flooded with *want* with similar ideas...I really like seeing shapes in things created by nature...and one thing the comes to mind is using a trunk of a tree with two branches serving as riser ends to mount limbs/levers on for a reverse draw crossbow (call it ~ Log Bow maybe jocolor)....and this little engine fits so well with the concept.

    Semi Ballista Log_bo10

    Do you plan on taking it a bit further or is this more of a research type of build for information and inspiration? cyclops

    Ivo



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    Post by hullutiedemies on Sat Dec 08, 2012 10:55 am

    Ivo wrote:Do you plan on taking it a bit further or is this more of a research type of build for information and inspiration?

    This was originally intented just for proving the concept and testing materials.
    But it worked so well that I need to re-build it. With properly shaped riser and trigger. This should make a fun pistol type pellet bow for backyard plinking.
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    Post by Ivo on Sat Dec 08, 2012 6:30 pm

    Good to hear! drunken Definitely looking forward to seeing it, would make my day!

    Ivo

    PS: Cool avatar...did you encounter any examples of that kind of chukonu in reality?



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    Post by hullutiedemies on Mon Dec 10, 2012 10:06 am

    Ivo wrote:PS: Cool avatar...did you encounter any examples of that kind of chukonu in reality?

    Thanks ,
    I have made one.
    I have not published any pictures yet, as it is still undergoing field testing and has mildly put "somewhat unfinished" appearance.

    My own primi-compound system with chuko-action and magazine spring, so it can be shot sideways.

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