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The 40mm Pucklegun and modern materials

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  • #46
    Here are some photos of the fabrication of the yoke that will be set in a socket on the carriage yet to be built. Upcycled a pair of heavy duty angle brackets to make the body of the yoke. I did the fit up and the welding of the trunnion blocks while on the gun then heated the corners to red hot to relax any spring or tension that would likely develop from the welding. Also fitted up the vanes that will add rigidity to the yoke. The welding went to H-E double toothpicks because i hadn’t remembered to grind away the zinc galvanizing on the angle brackets. Not my best, and i was getting impatient. I decided to go ahead and finish it and make a better one later. I remember one foreman in a fab shop eons ago, telling me “ fit, form, and function” It looks like a gun yoke, it fits the gun, and it does what it was designed to do.
    Click image for larger version

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    • #47
      Bending that U bracket must of been fun ?? I see the torch color on corners. Still must of been a good fight. Hey it's done and looking good !


      • #48
        Started on a second chamber block for herr puckle. This has low pressure chambers for shooting flares, smokes, and small doggie tennis balls out to about 350 yards. Low pressure is about 3000 pounds psi max Similar to a 20ga. Shotgun round or a 37mm flaregun round. The plate acts as the breech and each chamber is fitted into the counter bore and welded in place. This way the weld is not subjected to the pressures the chambers will sustain, however i am using air hardening tool steel weld rod with a 65000 psi tensile strength. Just to cover my axx. Will still make a heck of a boom!
        Click image for larger version

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        • #49
          Ok, Houston, we are ready to launch! Rather than some kind of field carriage, i decided to honor the original design by building a tripod gun mount.
          started with some repurposed box tube that i had from making some boat jackstands. The gun cradle had a pintle with a bearing plate. I have made a matching socket and bearing plate mounted to one leg of the tripod. I have just created a youtube channel dedicated to cannons i and friends have owned and shot, so videos of this Puckle will soon be made.
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          Last edited by Ironbearmarine; 01-23-2021, 01:09 AM.


          • #50
            Ironbear, how do you intend to proof test this baby? (hope you will post firing video's if possible) Jim


            • #51
              Originally posted by jmm03 View Post
              Ironbear, how do you intend to proof test this baby? (hope you will post firing video's if possible) Jim
              well Jim, the chambers were made of solid billets of heat treated chromoly alloyed steel, which is what is used for making high velocity big bore guns. Working pressures that are considered safe are figured at 4:1 ratios. Most high pressure users add a huge fudge factor of 6:1, giving 150,000 psi tensile strength a 15,000 psi safe chamber pressure which is what current 40mm high velocity m19 automatic guns achieve.
              So before i started this project i had already proved the chambers design by testing a chamber with smokeless modern powder. So i know, also from previous cannon builds that the barrel and chambers are safe. The real weak point is the recoil load on the grade 8 threaded stud. So the question is can the breech lock mechanism withstand the working pressures. Theoretically it can, but proof testing will show for sure. Videos will be provided.