[rahtreelimbs]

I am building a Billy Goat swinging hitch mount for a customer. The following pics are a factory made unit and the one that I am building. The 2x2 tube that goes into the hitch is welded solid at the gussets. I have everything tacked up and will weld it out down the line. The 2x2 tube is all welder up to the 3x6 tube. I did this as I didn't want any interference in the weld from the gussets. My question is how to weld this to minimize warpage as there are long runs of weld.[/URL[URL=http://s51.photobucket.com/user/rahtreelimbs/media/Mobile%20Uploads/2015-10/20151011_141321.jpg.html]

[Braehill]

You can skip around and weld in short runs, but this adds to the starts and stops. No matter what you do, you're going to get warping, and tubing's hard to put a preset in before it's welded. A piece of plate can be preset to account for the warping. Tight fit up on the gussets will help a little as this keeps it from pulling locally and spreads it out over the length of the area being welded. The good news is, the design in the pictures will warp towards the hitch.

What process are you using to weld it?

Len

[rahtreelimbs]

I should add that the 2x2 tube, 3x6 tube and the gussets are all 1/4" wall thickness. I am using MIG to weld this.

[Poland308]

Used to build roll off dumpster frames out of long tubes. Almost all the supports and gussets were on the inside of the frames. It's hard not to warp something like that. Try to not weld over 3 or 4 inches at a shot. And like Braehill said skip around. Plan out a pattern so you weld a little on one side and then somewhere almost opposite. Clamp it down or too something maybe even just another piece of tube and let it cool if you have to between welds.

[Sanford]

I built this one a few years back for a friend of mine. Not perfect but it worked well. I used 2x6 1/4" wall if I remember correctly.

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[Rupes]

Take this with a grain of salt as I've never seen these before here in Australia and I'm not an engineer, but I'd be more worried that its so stiff that it transfers all the vibrations and stress into the inch or so of tube between where the gussets end and hitch receiver? Smaller gussets finishing a couple inches back from where they are perhaps. As for warping perhaps with the corners of the gussets cut out you can reduce it it a little as the welds will be shorter and without the corners of the gussets locked in it won't be under as much internal tension when it cools.