Flatbed Trailer Home Build

[79vette]

So, I just wrapped up my 8 month long, on-again off-again flatbed trailer build and decided I'd post it up here in case anyone is planning something similar and might find the photos useful.
I dont see how to have more than 5 images in a single post. If theres a way to do this, let me know! Also go ahead and move this if there is a more appropriate forum for it. I was going to post in the 73-87 forum since thats mostly where I go, but I guess this isn't really a truck...

The trailer started life as a 70s camper trailer that someone cut the body off of. I bought it to get the axles and 2x 4" C channel frame sections and scrapped the rest. As you can see, the front crossmember is stamped sheet metal and the tongue is pierced through it. This is a particularly cheap and crappy way to build a trailer and does not really provide much support for the tongue.


Step 1 was to cut that junk out and weld in a 4" C channel front crossmember, and increase the deck width from 5.5' to 7'.


There was some twist to the existing old channel pieces, so I used some straps to square them up before welding the new crossmember in. Also cut the axles off and moved them back 2'. They were previously centered under the deck, and I reinstalled them with a 60/40 bias to the rear of the trailer for better tongue weight. I assume the RV trailer was super nose heavy (water/propane), justifying the forward axle position.

[79vette]

Then I mocked up a full-wrapped tongue, where the 4" channel piece making up the tongue sits underneath and supports the deck, which is an entirely separate structure. The tongue was extended back to the front spring hanger, hence "full wrapped". This is a much better design to support the most highly loaded section of the frame in the front half of the trailer, essentially making it an 8" channel section.


Then I had to play with the forklift briefly to get at the bottom of the new front crossmember to finish welding it.


The next step was to fit up and weld all the floor crossmembers, which are 3" channel on 14" centers. This is way overbuilt, and if I were to do it again I think I would use 2" channel instead with the same spacing to reduce weight.




The guy I bought it from was using it to haul steel. Compare these junk bolted angle "crossmembers" to the new pieces. Using this trailer in its old state to carry anything seems unsafe to me...

[79vette]

Finished cutting and welding the deck extensions. Its starting to look like a trailer!




Also finished mocking up the tongue and layed out the miter cuts.

[79vette]

Squared the new tongue and mocked up this new coupler. The trailer is designed to be towed by my M1009 using the pintle coupler bolted to the bumper, and needed about 10" of rise to get to the correct height. I also wanted it to be usable with normal height trucks, hence the channel bracket and adjustable lunette ring.










Checking out how the turning radius will be with the new wider deck. I probably should have made the tongue a bit longer, but this is the material I had and it will work fine.

[79vette]

Finished welding up the new tongue and coupler.




Also built this crappy plate to mount the jack. This is one of the things I regret; its super tall and not very stiff, which causes the jack to flex a bit when you are pushing the trailer around by hand.

[79vette]

Framed and skinned the fenders. Material is 16ga sheet and 1" x .063" tube. Not exactly "drive over", but they are plenty tough to stand and jump on when loading/unloading.
Also welded on some cheap stake pockets from eBay.







I dont know how I did anything without a plasma. 10/10 the best tool out there for cutting sheet, and I dont know how I lived without it.

[79vette]

Picked it up again with the forklift to weld the bottoms of all the crossmembers. Probably not an OSHA-approved lift...


Mounted up the toolbox, hitched it to the M1009 blazer and took it around the block. It seemed to track straight without "dog-legging" into the oncoming lane of traffic, so I managed to get the axles mostly perpendicular to the frame when welding in the new spring hangers. Yay!
Also added rub rails/tiedowns around all the stake pockets.




Brought it back, welded on the tie down rings, and moved on to paint.

[79vette]

Life got in the way for a bit, and the trailer sat for about a month before paint and all the pretty new steel rusted. Prepped with a wire wheel, etched with phosphoric acid, and sprayed primer and top coat.

[79vette]

Also painted the wheels, jack, safety chains and other accessories and got everything reassembled.

[79vette]

Installed the lights and wiring, installed and adjusted new electric brakes, repacked the wheel bearings, and fixed a "small" leak in the spare tire.

[79vette]

Started mocking up a spare tire mount. I still haven't built this because I dont like how low it hangs, and I am afraid it will get hung up on speed bumps. I also dont want the tire on the deck or on the side, so I'm not sure what else to do. Let me know if you have any great ideas!

[79vette]

Life got in the way again and caused another 5 month delay, but I finally finished the trailer up today. Took it to the lumberyard to pick up the deck lumber (7/8" apitong tongue and groove) last Friday, and got it all installed over the holiday weekend. First coat of oil is on, and it will get another one every day this week.









Before the first coat of oil was even dry, a friend of a friend was asking for help moving to a new place. No pics of the load but it hauled a bed, couch, bookcases, dining table and a set of chairs all in one go. Saved the other guys at least 3 trips with their short bed Tacoma and got it all in one go.

[biketopia]

Looks good, and quite well/over built. It definitely shouldn't flinch with most loads on it, any chance you have an empty weight?

[79vette]

Originally Posted by biketopia

Looks good, and quite well/over built. It definitely shouldn't flinch with most loads on it, any chance you have an empty weight?

Not yet, still need to take it to the scale. But I am pretty nervous it's going to be over 2200 lbs. The axles are tandem 3500 lb, so I'm worried the payload isn't going to be that great due to the trailer itself being excessively heavy. I'll post back when I get it weighed in the next week or 2

Maybe it will get some 5200 lb axles in the future...

[mr48chev]

That's a lot better looking than my "home built" trailer that I bought for 600 bucks a couple of years ago. It tows great but has axles that I think were welded up in a local high school welding class along with the rest of the trailer.

[79vette]

Originally Posted by mr48chev

That's a lot better looking than my "home built" trailer that I bought for 600 bucks a couple of years ago. It tows great but has axles that I think were welded up in a local high school welding class along with the rest of the trailer.

Ha. The lumber for the deck for mine cost more than $600, so I would say you got a pretty good deal...

I'm into this one about 3200 in materials and consumables and probably sixty hours of labor, but it was a good learning experience.

[biketopia]

Originally Posted by 79vette

Ha. The lumber for the deck for mine cost more than $600, so I would say you got a pretty good deal...

I'm into this one about 3200 in materials and consumables and probably sixty hours of labor, but it was a good learning experience.

Shoo, with the price of lumber and just material in general I can believe that! It stinks everything is so high, I tossed the idea around of building my own a few months ago after I sold off my 16' car trailer. Found a local outfit that does trailers really reasonably and called on the right day, snagged a 18'L 92W" car hauler, 4" c channel frame, wood deck, slide in ramps, LED lights, 3500lb axles with brakes, aluminum wheels with radial tires, 1900lb empty, for $3200 out the door. It certainly doesn't have the character or fit the theme of yours, plus you built it so there's the pride in that!