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  1. #1
    Join Date
    Apr 2008
    Location
    dallas,tx
    Posts
    207

    Default Round tubing advice needed

    A week or so ago, I posted pics of some strongman equipment I was building. Got it finished and now am ready for the second part. First part was the Farmers walk set-up. I used 3x3-3/16 and 3/8"x3. I filled the 3x3 with concrete. Each side weighed in at 90#. They were within .1# of each other. Pic 1 is the finished pieces. Pic 2 is a similar setup in action. Pic 3 is what the second part of the project is going to be. The uprights are 2.5 x 2.5 -3/16", secure at the botton with a 5/8" pin. The top section is going to be adjustable as we have people at our gym ranging from 5' to 6'-6". My question is on the round cross bar. I have 3 options. One would be to buy a
    piece of either solid 2" round or some thick wall 2" tubing. Both pretty pricy. Option 2- I have 2" round tubing with a wall thickness of .140 (10ga by the invoice)
    Optoin 3- I also have 2" round tubing .085 (14ga) and also a slightly smaller piece O.D. wise that would slide into this. It's wall thickness is .115. If I went this route, I was thinking I'd drill a few 1/2" holes in the outer piece and rosette weld the inner to the outer.

    In either options, the width/length of the tubing would be~4'. At the ends I am going to add gussets to add strength to the joint as it will only be butted. All told, I'm guessing the max weight I'd ever load and walk or stand with would be in the 700# range, with most use in the 4-500# range.
    If you have made it this far and am still here, thanks. I look forward to seeing what y'all suggest

    Scott
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  2. #2
    Join Date
    Jan 2008
    Location
    VA
    Posts
    298

    Default

    Is there a reason the yoke is as wide as it is? Less distance between the weights the less bending load on the tube. I would think that the standard .140 wall tubing would do well even at 700# There might be some flex that shows up in the weights springing in/out as you walk. You will have less flex by using two tubes one above the other than one inside the other.
    Weekend wannab racer with some welders.

  3. #3
    Join Date
    Apr 2008
    Location
    pine city mn.
    Posts
    20

    Default

    wouldnt it be easier to just work construction? i carry 70lb pails in each hand and go up and down loose sand trench banks, then sprint back to get more. lol


    for only carrying 700 lbs you are more than strong enough. I made a "A" frame for lifting the front of the car up so I can get the engine and tranny out. I used 2" diameter 1/8" wall tubing, some creative gussiting and laddering. and that easily held the 1 ton of weight.

    but your goal is weight any how, so why not make the frame heavy? you welds will be more than strong enough.

  4. #4
    Join Date
    Mar 2008
    Location
    Torrance, Ca
    Posts
    83

    Default

    Tubing is much stronger than solid bar stock. Wall thickness of .140 will be plenty strong. Don't know about the ability of the .085 to withstand the kind of abuse 700lb weights would doll out over an extended period of time. We use .085 for motorcycle frames all the time and it holds up good with proper gusseting. The .085 should work. I don't think you would have to double up on it. So I guess what I'm saying is the .140 will/should never wear out but the .080 has more of a chance to. .o2
    Dynasty 200 DX
    Lincoln 140
    O/A
    Gradatim vincimus
    "We conquer by degrees."

  5. #5
    Join Date
    Feb 2008
    Posts
    8

    Default

    I used 1.5" pipe (1.9" OD x .145" wall) that has 36ksi yield strength, on a 4ft long bar supported 15" in from each end (18" wide strip in the middle). It can support 595lbs on each end no problem.

    595lbs = 350lbs x 1.7 (live load)

    I will deflect almost 1/4" at the ends, but will be fine with the 700lbs loading

    As a side note, tubing is not much stronger than bar stock, for a given OD the bending strength will be similar, but the bar stock will have more shear strength.

    Now, on a lb per lb basis, the tubing will be much stronger.
    Last edited by NAS-NAS; 05-05-2008 at 01:29 PM.

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