DIY Platform and drum is like a tunning fork HELP!

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  • fnf01
    Speed Bag Trainee
    • Aug 2015
    • 3

    DIY Platform and drum is like a tunning fork HELP!

    Hi all,
    So this is my first non introduction post, but I've gotten a lot of info and ideas reading on here prior so thanks everyone. I need some specific help or ideas for my new setup/creation. So long story short this project has being on going for a couple months now and I finally got it finished and up on the wall. The bad news is any hits to the bag and the whole thing starts vibrating like a tuning fork!! So here's the run down:

    I have a 2.75" thick 29" wide octagon hickory and mahogany drum (the wood types alternate each row)
    the drum is bolted to a 3/8" thick 29" wide steel octagon plate
    The plate is welded to a angle braces of 2" square tube steel that has 3/8" walls (I think I can double check when I get home)
    that setup is welded to 1.25" dia pipe that slides over 1" dia pipe for a fully adjustable set up over a 32" range.
    The whole platform is anchored to a basement wall via 5/16 lag screws into 2x4's that are drilled and pined into the solid concrete walls.

    Also as the picture indicates its a corner mounted system 4 bolts on one wall 4 on the other

    So I notice a couple things:
    First I'm not a great welder nor my father who helped out so while the welds do their job they don't look pretty but more pressing we got the plate a little too hot so its warped a bit so some of the outside edges don't make contact with the wood drum since the bolts connecting them are in the middle more (Thinking of putting some rubber between them like a gasket to fill these gaps. Would that work?)

    Also I've read a lot of the other threads about vibrations but those were all stationary platforms that I could find. And they suggest sand, while I'm not super opposed to it I'd rather not have sand up there for adjusting ease. It already weighs ~60lbs for the drum and another ~60lbs for the steel plate plus all the square tube so adjusting becomes a work out itself already lol.

    As for the vibrations with just a hand test and being able to actually see it moving, its really bad on the platform (I read a thread with a water cup test, my cup would jump off the platform if I did it), if I move my hand to the slide poles it dampens severely, the guide poles that don't move I can barely feel it if at all, and then the wall/ anchor points I cant feel it at all.

    I do know that if someone either pulls down or pushes up on the platform while another is bagging like you see in pro boxers open workouts leading up to fights (generally some huge body guard lol) helps the vibrating immensely

    Any ideas, suggestions, ect on what I can do?

    Thanks (hopefully photos work)
    Attached Files
  • Speedbag Seaweed Man
    Speed Bag Guru
    • Apr 2015
    • 442

    #2
    Hi fnf01, welcome to speedbagforum

    Sounds to me like the lack of triangulation in your bracing above the drum could be the main culprit here.
    I am talking about the steel framing (visible in picture 3).
    I see there is a triangle created but it is of minimum significance due to it's very acute angle. It is the diagonal bar in this part of the design that is relied upon to add rigidity and a diagonal brace is most effective when it is nearing 45 degrees. You want this part of the frame to be solid enough to pass the load onto the vertical bars without movement. And your vertical bars to be stiff enough and not too long so they aren't caused to wobble. Sounds like your mount to the wall is solid though. But your bracing (triangles) looks like it is only about 10 degrees..
    So it is adding minimum bracing effect.
    By Re-positioning these braces to a higher angle (bigger triangle) you will find it becomes more rigid. You will lose a bit of height and range in your adjustment but hopefully will still be able to raise it high enough to use properly.
    This is why most wall mounted drums have framing attaching them to the wall which look like two triangles.
    Cool looking rig you have made though, I like your wood work!
    Also an adjustable setup will always struggle to be as solid as a non adjustable, due to the moving parts but adjustable is what a lot of people want. I gave up on the idea and prefer to stand on a bit of plywood etc to adjust my height.
    As for the plate that attaches the drum to the rest of the frame, and it being warped with a gap in the bolting point, are you using coach bolts that go through to the other side if the wooden drum, or screws? A nut and bolt should be able to squeeze a minor gap shut as you tighten them up, otherwise can you smack them closer with a hammer first without breaking the weld?
    I have added two pictures to help demonstrate my theory. One picture has quite good triangulation, the other doesn't. I would bet the one that does is far more solid to bag on and produces a way better rebound.

    Building the rig is part of the fun, enjoy your journey
    Attached Files

    Comment

    • fnf01
      Speed Bag Trainee
      • Aug 2015
      • 3

      #3
      Thanks for the input Seawead Man I hadn't thought of the triangulation that way, definitely something to consider for my next build, not sure there's anything I can do about it now as everything is welded and cut, maybe I could add more material I'll have to think in it. As for the plate its the outside edges that are gapped and there are no bolts on that outside edges. I'm using 5/16 bolts that would definitely squish them together but they are so near the center to not have any affect on the outer edge.

      Thanks I have another drum in the works that much more complicated. This one took like 20min to put together instead of 2 weeks like my other one.

      Comment

      • Speedbag Seaweed Man
        Speed Bag Guru
        • Apr 2015
        • 442

        #4
        Cool. Looking forward to seeing what you create on your next build too and bag on.

        Comment

        • swfl
          Speed Bag Guru
          • Apr 2013
          • 274

          #5
          The wood work looks very nice. You may be able to brace directly to the floor joist at the leading edge to take some of the vibration out.

          Comment

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