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    Pellethuntr Builds A Mantis Copy

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    Pellethuntr
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    Pellethuntr Builds A Mantis Copy

    Post by Pellethuntr on Sat May 03, 2014 4:47 am

    Hi guys, it's been a while since I did any crossbow work.. I came across the Mantis crossbow at some point in my Google searching and was inspired to build a similar bow

    I apologize for not taking any pictures yet.. The gas piston is completed, the limbs are mostly completed and I am currently working on the riser 

    I will post pictures asap for your enjoyment Very Happy
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    Todd the archer
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    Re: Pellethuntr Builds A Mantis Copy

    Post by Todd the archer on Sun May 04, 2014 5:35 am

    The mantis is a very interesting design, looking forward to what you come up with.


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    Re: Pellethuntr Builds A Mantis Copy

    Post by Pellethuntr on Mon May 05, 2014 9:58 am

    Here are some pictures of the parts we have fabricated so far:

    First is the piston.. It is a very simple design, the steel rod is threaded into a larger diameter steel piston that is 3" long and has two o-rings that internally seal it to the inside of the tube.. Both ends are soldered in place and then a shrader valve is installed for filling and adjusting the air pressure

    Right now there is 400 psi of air acting on this piston when it is at rest


    The next few pics are of the current progress of the "limbs" and the brackets that mount them to the stock and allow them to pivot backwards 





    We are in the process of making the "cams" and the rollers for the end of the "limb" tips

    I will post more pics as the parts become available

    Enjoy!
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    Re: Pellethuntr Builds A Mantis Copy

    Post by Anatine Duo on Mon May 05, 2014 12:19 pm

    This looks like fun!
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    Re: Pellethuntr Builds A Mantis Copy

    Post by Pellethuntr on Fri May 30, 2014 9:42 am

    Here is an update for the last week or two:

    I was able to have the limb brackets welded to the mounting plates by a local welder, I am proficient in MIG welding but I have almost no experience welding aluminum so just to be safe I had a pro do it. The nylon washers make the draw very smooth and quiet.


    I was also able to get the limbs mounted on the stock as you can see in the photo and I turned the limb bushings and one of the two rollers for the limb tips:


    Here it is at full draw. We are getting 24" of string travel and 4.5" of piston compression.


    We still need to cut out the cams and get them mounted to the limbs before we can proceed any further. I am waiting on more aluminum stock to arrive in the mail. This is what the cams will look like:


    And at full draw:
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    Samuel Wilhelm
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    Re: Pellethuntr Builds A Mantis Copy

    Post by Samuel Wilhelm on Fri May 30, 2014 2:46 pm

    when do you think it will be finished? can't wait to see it in action!
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    Re: Pellethuntr Builds A Mantis Copy

    Post by Pellethuntr on Fri May 30, 2014 8:05 pm

    Samuel Wilhelm wrote:when do you think it will be finished? can't wait to see it in action!

    Thanks for the interest Sam!

    I am gonna need a few weeks to get this crossbow done.. I am waiting on aluminum stock that should come this Monday.. I am starting a new job so most of my time in the next few weeks will be dedicated to that until I get adjusted.. I would say by mid July we will be letting bolts fly Very Happy

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    Re: Pellethuntr Builds A Mantis Copy

    Post by jeep on Sat May 31, 2014 3:18 am

    Fantastic job! and pro realisation... I think to balance the forces it should be better to link the two front bracket,it will give you also a place to put the aiming apparatus. To avoid torsions would it be possible to put the cams junction in the middle of the limbs ,not under. To help, open the following link, it is the original patent of Robert Van House. Drawing are very clear :http://www.freepatentsonline.com/4169456.pdf (1978). Mi next crossbow will certainly look very close from this. Impatient to see the result. It is like the ultimate crossbow or what ever, dart projector!!!
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    Re: Pellethuntr Builds A Mantis Copy

    Post by Samuel Wilhelm on Sat May 31, 2014 5:54 am

    awesome Very Happy
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    Re: Pellethuntr Builds A Mantis Copy

    Post by Pellethuntr on Sat May 31, 2014 6:26 am

    jeep wrote:Fantastic job! and pro realisation... I think to balance the forces it should be better to link the two front bracket,it will give you also a place to put the aiming apparatus. To avoid torsions would it be possible to put the cams junction in the middle of the limbs ,not under. To help, open the following link, it is the original patent of Robert Van House. Drawing are very clear :http://www.freepatentsonline.com/4169456.pdf (1978). Mi next crossbow will certainly look very close from this. Impatient to see the result. It is like the ultimate crossbow or what ever, dart projector!!!

    Thanks for the interest Jeep! 

    I have been considering mounting a piece between the two front brackets for added stability.. I guess we will see how it holds up after shooting a few bolts.. I will be mounting a scope to this so no need for open sights, why have a 100 yard crossbow if you can't hit a 100 yard target right?

    The cam location is something that I have been battling with since the start.. The problem is that if they are centered on the limb they will not clear the arrow track when attached to the piston.. I am hoping that there is not too much counter force when drawing as to put excessive stress on that joint

    Thank you for the patent!
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    Re: Pellethuntr Builds A Mantis Copy

    Post by patandjali on Sat May 31, 2014 11:38 am

    Nice proiect.
    Maybe this helps build cylinder air
    https://www.youtube.com/watch?v=VcoiFQwV7u4

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    Re: Pellethuntr Builds A Mantis Copy

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