3D printed compound bow and legolas magazine.

Discussion in 'Show off your homemades!' started by Algstone, Jan 5, 2021.

  1. Algstone

    Algstone New Member

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    After seeing Joerg’s legolas designs I decided to design a legolas myself. The kinds of bow Joerg designed around are expensive in my country so I found the cheapest bow I could afford and built a legolas magazine for it. That worked really well and the design is a success I'm my opinion. The bow I use is a Man Kung Cb30. Here is a picture of that design:
    20210105_163822.jpg

    Once I had completed that design I really wanted to get away from having to buy a bow. So I started to design a 3d printable compound bow for my legolas mag. My complete bow and legolas magazine can be made cheaper than the cheapest compound bow I can buy in my country. Here is a picture of that design:

    20210105_122952.jpg

    The bow uses pvc electrical conduit for limbs and aluminium tube for the barrel. It is meant to be a self defence weapon for people who can't own a gun or don't want to own a gun. The bolts weigh 270 grain. I am comfortable that a gut shot from this, with a broadhead will take the fight out of most men.

    The barrel is replaceable so the bow can be used as a compound bow with standard arrows too (although I have not tried this) .

    20210105_122737.jpg 20210105_122720.jpg 20210105_122509.jpg 20210105_121330.jpg 20210105_121118.jpg

    The bow can be fired vertically or horizontally as is the user's preference. There are 3 cam profiles on each cam. One profile is for the bolt sting, another for the cam syncing and yet another for latex tubes which offer additional energy to the bow.

    20210105_125107.jpg

    If you have questions I will be happy to answer them if possible.
     
    Saipol likes this.
  2. Markus Oswald

    Markus Oswald New Member

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    Hi, nice design!
    Im wondering that printed pvc can withstand reasonable forces.
    Waht is the strength of the printed plastic? (normal to printinglayers)
     

  3. Algstone

    Algstone New Member

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    HI Marcus,
    Thanks for the compliment.

    The limbs are white pvc tube and are not printed.

    Printed parts are not as strong as moulded parts. When I started I didn't think it was possible to build but I'm very impressed with what the 3d prints can handle. I am testing the bow to see when and why parts fail and then redesigning to make the necessary changes so it's a work in progress. I've just made the riser stronger. (busy printing it)
    20210109_173233.jpg
    It's been printing for 20 hours now and has about 10 hours to go.
    20210109_173328.jpg


    Do you have a 3d printer?
     
    Saipol likes this.
  4. Markus Oswald

    Markus Oswald New Member

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    No I dont have one, but from time to time I think about buying one.
    I expect once you have it you'll may use it more often.
    But as mentioned ,... the biggest backdraw -> The parts are usually very weak (my experience so far with parts from friends)
    Specially for the moving parts on the bow the strength/weight ratio really matters.
     
  5. Algstone

    Algstone New Member

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    Strength of the parts has a lot to do with how you print them. You will be surprised by how strong they can be. There are guys who have printed semi auto 9mm uzi type guns with pla that last 1000's of rounds.

     
    Markus Oswald likes this.
  6. Markus Oswald

    Markus Oswald New Member

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    I also heard about carbon reinforced filaments.
    For some parts (cams,..etc) this might be good idea.
     
  7. Algstone

    Algstone New Member

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    Thanks for the suggestion. After heat treating the PLA its holding up very well. I will go for carbon fiber if the riser suffers creep deformation over time. So far so good.