Trailer build question

[oosik]

handirifle,
You are correct - the treated 4x4's transfer the load to the doubled 2x12's and then to the axles.

 

[Gary Fowler]

How would I do that?

Build it like a truss. Separate the pipes vertically from each other by at least 3" by welding angle iron pieces between the lengths of pipe. You would need a piece on each end and one or two in between. To have maximum strength, the bottom pipe must be bent upward on each end right past the end spacer so that the top and bottom pipes can be welded together. Mitre the bottom pipe so it joins neatly to the top one and weld with full penetrating weld. This way the truss cant bend or move without breaking the welds at the end. The truss has to be securely placed and braced so that it remains vertical and cant flip to the side during operation.
Also the bottom pipe could be smaller than the top since it is all loading in tension. I did something similar on some 40' long trailers I built once by adding a tension rod on the bottom of a 40' span of 6" channel. The tension rod was a piece of sucker rod from an oil well about 3/4" in diameter. I used 1" pipe welded on the bottom of 2x2 angle. I made four of these for each side. I slipped the 1" pipe over the 3/4" sucker rod and spaced them out at one on each end next to the bend at the end and 2 equally spaced in the middle. The pipe allowed the sucker rod to move (stretch) if need be without putting a side strain on any of the intermediate supports. I don't know if this was needed or that I might could have welded them tight, but the trailers never flexed nor broke any welds in the 20 years that I know that they were used to haul cotton to the gin with average load of 12K pounds + the trailer weight.

 

[downslope]

handirifle,
You are correct - the treated 4x4's transfer the load to the doubled 2x12's and then to the axles.

I'm trying to understand what you used the 3" pipe for. I thought when purchasing a new farm running gear it comes complete with the "pole" (or in some designs, two poles) that connect the the front end and rear end axles. Or does the Horst not come with the pole(s) and that's what you supplied your own pipe for? I've only purchased used beds and gear so I never thought about how they come new.

 

[handirifle]

Gary
Thanks for the explanation, but I honestly have to say that is WAY beyond the scope of MY abilities. I think I will stack them, welded in strips (If I do it like this at all) and brace with flat iron on the sides. That should be strong enough for my needs.

 

[Travelover]

Gary
Thanks for the explanation, but I honestly have to say that is WAY beyond the scope of MY abilities. I think I will stack them, welded in strips (If I do it like this at all) and brace with flat iron on the sides. That should be strong enough for my needs.

You can just weld the two pieces together, but it will not be as strong as if you separated them. The magic of a truss is in the vertical distance between the two horizontal members. In any case, it is important to weld a sturdy piece across each end (side to side) to resist twisting of the frame over its length.

 

[handirifle]

Yea that makes sense, and I do plan on cross bracing as well, which will help some, in that respect. Question: if I used 2@2.5" tubes, stacked, for the main frame, how thick should the flat bar on the sides be? Would 1/8" suffice? Also would it need to be one continuous piece or could it be in sections?

I would love to be able to build a truss, but I do not have anywhere near the setup to keep all the pieces in place to weld, and insure it all stayed straight. If I attempted that it would come out a real mess and a waste of a lot of metal. That I cannot afford.

 

[handirifle]

Yea that makes sense, and I do plan on cross bracing as well, which will help some, in that respect. Question: if I used 2@2.5" tubes, stacked, for the main frame, how thick should the flat bar on the sides be? Would 1/8" suffice? Also would it need to be one continuous piece or could it be in sections?

I would love to be able to build a truss, but I do not have anywhere near the setup to keep all the pieces in place to weld, and insure it all stayed straight. If I attempted that it would come out a real mess and a waste of a lot of metal. That I cannot afford.

Also, correct me if I am wrong, but wouldn't a truss like above, also be subject to twisting? Seems to my, non-engineer mind, that the tubes stacked directly on top of each other and flat bar welded to the sides would actually be stronger, in resisting torsional twist. Am I wrong?

 

[Travelover]

Yea that makes sense, and I do plan on cross bracing as well, which will help some, in that respect. Question: if I used 2@2.5" tubes, stacked, for the main frame, how thick should the flat bar on the sides be? Would 1/8" suffice? Also would it need to be one continuous piece or could it be in sections?

I would love to be able to build a truss, but I do not have anywhere near the setup to keep all the pieces in place to weld, and insure it all stayed straight. If I attempted that it would come out a real mess and a waste of a lot of metal. That I cannot afford.

I'm not following. Are you saying you want to stack two 2.5" pipes, one directly on top of the other? If so, I'm missing what the flat bar on the sides would be.

 

[MossRoad]

There is a local steel supply shop that sells used steel round pipe in various diameters. It is usually dirt cheap compared to new steel. I got this idea of using stacked tubing (3" or larger) for the frame with gussets welded to make them as one piece or close.

I am thinking of something along the lines of a 7x12 flat bed capable of 4,000lbs or less. Use it to haul my Massey Furgeson 1010 or riding mower or lumber or firewood. I have a 4x8 utility that is very heavily built, that I mostly use for hauling fresh cut firewood, but it has 16" sides and a flat bed would be a nice addition. I have hauled 2 complete pallets of used brick on the 4x8 with zero issues. Tires are rated for 3500lbs combined.

Is this a lame idea or decent? I am not sure what wall diameter of the pipes are but I can easily find out tomorrow with a phone call. What thickness should I look for?

You planning on using this on public roads?

 

[handirifle]

Yes, why?