Superstrut/ Channel need trailer build advice

[Miriam C.]

My Mike would like to know if we can use #12g or #14g superstrut and make our own bolt together trailer.

Do we need to weld? What kind of bolts?

Advice or information would be greatly appreciated.

Miriam

[Chuck Craven]

Some one on this site has used angle iron to build a bolt together frame.
There should be no reason why it can’t be done, if one would keep the total weight down to about 1500 lbs. That strut is too week to use.
I would think that if you used 2” X 3” X 1/4” wall angle iron and grade 5 or 8 bolts it could be done. Use nylon inserted lock nuts, lock washers and lock tight. If standard leaf springs and axels were used, you could use say 2” by 4” angle on the inside of the frame for the spring hangers. And a flat 4” wide plat bolted to the angle 2” angle frame for the outside spring hanger. My utility trailer is a bolt to gather trailer made from a dodge mini van rear axel and springs. I used 4 x 6 pressure treated wood posts for the sides bolted the spring hangers to that. And used 3” x 3” ¼” angle iron for the front and rear cross members. The tongue is 3” sed 40 black iron pipe with angle iron cross supports all bolted together. I would not hesitate to hall a ton on it.

Chuck

[angib]

Miriam,

I looked up superstrut properties and part of the answer is that the idea isn't daft. The 12g superstrut (1.625"x1.625"x0.105" channel with extra lips) has a strength 40% higher than a 2"x2"x1/4" angle. This assumes the channel is oriented with the flanges top and bottom (ie, open side) - although even if mounted the other way, the strength isn't too bad - better than a 2"x2"x3/16" angle.

However, if you're looking at superstrut to make a bolt-together trailer, using just the original holes, then I don't see how you can make strong enough joints in several important places.

The alternative is to drill and bolt the superstrut, or even weld it (beware - galvanised!), in which case it's hard to see what advantage the superstrut has over normal steel angles or tubes.

Andrew

[Miriam C.]

Thanks Andrew,
The connections have me puzzled more than the strength. I get a real good price on steel superstrut. I will admit to thinking of going to E instead of A, which is almost twice as big.

Thomas and Betts catalog lists connectors but I have no way of assessing their ability to hold up under tow. I hope I am making sense here. In my mind I can put it together but I am not an engineer or draftsman and I know what looks good may come apart with the first pull.

I appreciate your taking the time to look it up for me.

Miriam

[angib]

I think there's no question that the E section is strong enough for a light trailer and it could be used with the open side down, which would look better and be easier to join (though it would always have water sitting in the two returns!).

I'm almost coming round to thinking this could be possible - but I don't think I would ever trust fasteners intended for static use being used under dynamic loading.

Andrew

[Chuck Craven]

I have experience with Unistrut but not the Superstrut. I know that Unistrut is weaker than it is rated for, unless they have changed there data sheets lately. I have always had problems with the folded ends distorting. I have also had problems with the bolts coming loose in a static fixed location. The spring nuts are nice for assembling but I think it is to small and not manufactured to a good close tolerance. If one bolts it together it is easer to bolt angle iron with gusset plates at the critical points. What type and size of a tear are you planning on building? Size and weight is the most critical when building your frame.
As for welding look for a car body shop or a repair shop most have at least some one that can weld. If you cut the steel and have a good drawing of what you want the cost is not that expensive to have welding done. You could have the metal bolted with cheap hardware bolts then have it welded. That will shorten the welding time and lower the cost.
Look around and take your plans with you when shopping for a welder. You may be pleasantly surprised.
Chuck

[Miriam C.]

Andrew, you are a blessing.

E is outragiously expensive but no boubt stronge enough. The guys use A to make racks for 500 mcm wire. Never bends. The nuts and bolts seem to hold well (from what I can read). Though the catalog does say: "if connections will be subjected to dynamic or seismic loading conditions" they suggest calling the factory. The the fittings and brackets don't give too much detail about loading. Just that 1 5/8" wide and 1/4" thick. Maybe need to have Mike call factory next week and see if they have a specific way to bolt together for something that is going to be jerked and pulled a lot. I know they (some of the contractor houses) make racks (like a pot rack) to put things on when they want to have them adjustable.

Thanks for you efforts. It really is a good price if can be done.

Miriam

[Miriam C.]

Chuck,
Thanks for the suggestion. I am avoiding welding because I wanted to do this myself partly and I can get the superstrut dirt cheap. I am going for as light as I can get without doing the Ultralight. Think I will come at around 750# when the paint and hardware are added. 5x 5x8 is my sacrifice. Wanted 5x10 but got too complicated and expensive. However, If I can use the Superstrut all bets are off as I will get it in 10' lengths anyway, and gotta order by the 100's. The superstrut 1200A is 1.9# per ft. plus fittings.

Greatfully,
Miriam

[Chuck Craven]

Superstrut! Is that the galvanized stuff? I have seen some 1/8” galvanized T and L plates. Used for post and beam barn timber connectors. If you can find them and use them by bolting through the strut sidewall, top and bottom. You could also use triangle gussets on the corners. Use a grade 5 bolt and shack proof nuts. It should work. Your trailer being around 700 lbs is purity light. The tongue is the only problem that I can see. But a square tube like 2 x 3 with a 3/16 wall should work for that. Maybe run that under the superstrut but weld angle tabs to this for bolting it to the struts. Don’t drill through the tongue except for mounting the hitch coupler! If you drill a “few” holes though the bottom of the strut to drain out any standing water. I just would not use their spring nuts or clip nuts. If one of them came loose the frame will pull apart.
Looks like a doable light frame.
Chuck

[Mitheral]

The tongue is the only problem that I can see. But a square tube like 2 x 3 with a 3/16 wall should work for that. Maybe run that under the superstrut but weld angle tabs to this for bolting it to the struts. Don’t drill through the tongue except for mounting the hitch coupler!

No need for welded tabs, use a u-bolt arrangement like they use to fasten flatdecks to trucks or axles to springs.

[Chuck Craven]

Well the U bolts would stick up in the floor! If the U bolts came loose you will have a tongue but no trailer. I have come up with another idea! What it the dimensions of the superstrut?
Chuck

[Mitheral]

Well the U bolts would stick up in the floor! If the U bolts came loose you will have a tongue but no trailer.

Um, point them the other way? One could easily rout out a 3/8-1/2 groove in the floor if there wasn't clearance provided by framing members for the bottom of the U.

If you wanted to get really tricky you could go thru the floor of the trailer, straddle the frame, around the tongue and then bolt on the bottom plates.

[Miriam C.]

Good discussion,
It seems superstrut is different to different people so for those of you who want to do a mental project here is the URL for Thomas & Betts.
http://elec-[url]cat.tnb.com/tnbcat/tnbcat/SS_home_page_dsp.build_catalog_home_page[/url]

I am glad there is interest in this. Superstrut has whole catalog of connectors, braces, ubolts and such.

Might be fun to see if this can work.

Miriam

[Chuck Craven]

You can drill holes for bolts through the top of the tongue but then you have to snake the nuts down the tube and use threadlock from locktight. Use the permanent type.

Andrew! Does this look feasible?
Use 3/8” plywood for the top and the bottom of the floor. Sandwiching the unistrut and bolt through both pieces of plywood and the sidewall framing. Using flat head ¼” or 5/16” bolts with flat washers and lock nuts. Say every 12” and 3” at the corners. Unistrut cross members at 16” centers.
Should look like this if I can get the picture to come across.

Chuck

[Miriam C.]

Chuck,
I think 16" on center is serious overbuild. 12 g superstrut is as Andrew said 40% stronger than angle. I am going to sandwich the floor with 1/4 on bottom and 1/2 on top with framing of split 2x4's making almost 1x3s. Just in case I want to jump around in it. It will be done as most are done here. I can't picture the reason for sandwiching the trailer itself. The unistrut shouldn't need more than to be u-bolted to the axle. I am thinking of backing two unistrut strips together Per. catalog instructions for the axle. These may need welding. I will leave them long and run them like Mike and Andrew have the axle in the Ultralight. Does that make sense to anyone? Am I alone here?

The real problem is connections. The connectors are intended to be in fixed applications. Check through the URL for fastners and you will see why Andrew hesitated.

Miriam