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A couple Gantry Questions of my own...

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  • A couple Gantry Questions of my own...

    Fellas,
    I would like to build a gantry crane for my basement shop. Granted, I've been torn between doing this, and NOT doing this, because of the low headroom in my basement. Still though, a gantry crane would be very useful as I acquire more machines. I would DEFINITELY want to build w/ adjustable legs, maybe something similar to THIS: http://metalworking.com/DropBox/_200...o_Basement.jpg
    One thing I am NOT so sure about, is if I can build a Gantry rated for 2 tons, with adjustable legs??? Doesn't all the weight ride on the adjustable pins, that are used to lower and raise the legs??? How much weight can you put on even the biggest pins available? I would probably build this whole thing out of 3x3 or 4x4 square tube, 1/4" wall.
    I would of course have to decide on what size I Beam is needed, for an 8' 3" span (would like Gantry to be able to span across an 8' welding table, also to be built in future.

    One other concern is how intelligent would it be for me to use an I beam that I was given recently? Consider for one second that the I Beam is big enough for the task, and add to the equation the fact that the I beam has been out in the front yard of a jobsite I've been working on for a while now. It had white paint on it at one time, and that kept it from really rusting badly. It's got a lot of surface rust all over it, but it would come off with wire brush easily. Is this a bad idea to just go pick this beam up and use it for my crane, not knowing what kind of stresses it's been put through? I mean, visually, I don't see any cracks, or damage/etc. IF I recall, the beam is about 10" tall, with a 6" flange width ( I THINK)
    I know it is PLENTY big, as most 2 ton Gantrys I've seen, use a smaller beam than this anyhow.
    Well, I'm just wondering what you guys think about this, and would appreciate any insight you might have. This is something I could use a bit of help on.
    Thanks so much as always guys!

  • #2
    I think youd be fine with 3x3 3/16 wall tube and a 5/8 hitch pin. I built one for my shop that is about 17' wide inside. I made it out of 2 1/2x2 1/2 ,3/16wall and the adustable legs are made out of hitch recever tube with 2x2 1/4 wall legs that move up and down. I just used a 5/8 hitch pin on each leg. I've had 5 tonnes hanging from the thing. Mine has swivel casters on it. I'll try to get some pics. The I beam I used for it was a 3/8'' thick and 8'' tall.

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    • #3
      Paul,
      I can comment on the load bearing of the pins. Before I say anything though, please understand that while I have an engineering degree, I am not a registered PE with the license to sign off on any designs like this. This is merely an example of what I have done! Is that enough lawyers?

      Anyway, I built four jackstands at the end of last year. I wanted something tall enough to hold my Suburban high in the air (it is lifted with big tires). I also wanted something sturdy, and something with a heavy duty rating. I settled on 12 Tons EACH stand. The sliding piece is 3x3x3/16" It has 5 holes in it for adjustment. The pins I used I got from McMaster car for ~$8 each. One pin per stand, double shear joint, 7/8" diameter. It will hold significantly more than 12T in theory, which is good for my factor of safety.

      Trying to hold up an I beam plus the upright plus 2T should be easy with one moderate pin. How big, I can't say exactly since I don't know how big your beam is, nor what pins you would use. I would err on the bigger size though. I would hate to size something too small for your uses and have it collapse on top of someone.

      Sorry to be so nebulus, but I see this as very similar to advising someone how to weld on a gas tank... I hope at least it gives you an idea on the size of pin required.

      Joshua

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      • #4
        Fellas,
        YOu guys have already been a great help. Thanks!

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