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Strength of Steel

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  • Strength of Steel

    Hi, I am building a crane to raise and support the front end of a motorcycle. My idea is to make it very much like and engine crane, except the arm will be stable and us a pin that will attach to the bottom of the triple tree.

    I am planning on using square tubular steel and my question is what diameter and thickness square tube should I use? I am guessing the weight to be less than 500 lbs.

    I was thinking 3x3x1/4 or 3x3x1/8?

    Is there a formula for figuring this out.

  • #2
    Without seeing specific designs its impossible to size material, but likely for motorcycles a tube 1/8x2x2 or better would be sufficient if this is designed anything like an engine crane, but again, only a guess as to what is going on, length is one of the most important factors.


    • #3
      You might download BeamBoy and see if you can calculate what you need. Or check out the dimensions on a lightweight shop crane if your arm design is similar.
      --- RJL ----------------------------------------------

      Ordinarily I'm insane, but I have lucid moments when I'm merely stupid.


      • #4
        My $99 engine crane is made from 2.5x2.5x1/8" mild steel tubing. The boom is about 4 feet long when fully extended. As I recall it is only rated for 1/2 ton when fully extended. It successfully lifted the Chevy 454 ( a bit over 600 pounds) out of my motor home without any noticeable deflection. Being that it was made in China, I was more worried about the welds than the steel. It has also raised both my Buell Blast (350 pounds) and my sons Kawasaki (400#) completely off the ground for tire changes etc, like they were not there. The green leg mods to clear the engine hump are my handiwork, also welded from 2.5x2.5x1/8" mild steel.

        I would probably say that 2x2x1/8" would be strong enough for what you want, but I'd still go with the larger while steel is cheap again.
        Last edited by smyrna5; 09-17-2009, 07:49 PM.
        Lincoln 175HD
        Miller Thunderbolt AC/DC
        Smith AW1, Dillon (Henrob) Mark III & Smith Quickbraze Little Torch


        • #5
          Thanks for all the info.