Ubolts to attach the floor to trailer?

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Re: Ubolts to attach the floor to trailer?

Postby Vesselhead » Wed Jun 21, 2017 10:37 pm

working on it wrote:
aggie79 wrote:Did I read right that your floor will be insulated and the bottom plywood will be 3/4" thick? If so, the 3/4" plywood is overkill. You really don't need much in the way of fasteners to attach the teardrop shell to the frame. I used self-tapping trailer deck screws that go directly into the 2" tube steel frame.
  • I didn't insulate, but installed my floor in two stages, with two types of fasteners, making a 3/4" floor from two different plywood sheets.
  • 1)The base, a 4'x 8' sheet of 1/2" birch plywood (it sat unused in my wood storage shed for 10-5 years, very dry and hard), was centered on my 50" wide x 97" frame (original was 50" x 60", rectangular tubing added), with 1" frame showing on the sides, and 1" on the rear (the front was set flush with the frame). I used eight 3/8" carriage bolts to the original frame tubing, at the old front and rear tube, slightly countersunk to not have the bolt heads protrude too much above the plywood.
  • 2)Then, I applied a full, thick coat of Titebond 2 adhesive to cover the birch base, and placed a sheet of 1/4" Lauan over it, using Tek screws to secure it to the perimeter of the frame. I started at the back, working forward, pressing out the glue with a roller as I went. I used around 36-38 screws, if I remember correctly. I sat some feed bags in the center, to hold it flat, and let it dry for a week or so.
  • I probably didn't need to do the double-layer floor, but, after countersinking the carriage bolts, I needed to cover the heads anyway, so the Lauan was an afterthought, which brought the floor thickness to 3/4" (nominal), to match the plywood thicknessI was going to use for the remainder of the build. I used the birch, just to use it up, and had planned to use linoleum to finish the floor, but I liked the grain of the Lauan, so it became my floor surface. I had always intended to screw down the perimeter, so that served the double purpose of securing the top sheet, also. Looking back, I would've just used the perimeter screws, but I was in overkill mode, so why not use two methods of fastening down the floor?
  • 86939 1/2" birch plywood base, with carriage bolts
  • 86940 top sheet screwed and glued on; drying out
  • 86942 finished floor, stained, polyurethaned

I hope your next project is a boat. Sounds like you have marine grade ply now!
I'm probably overbuilding a bit, but our son is rambunctious so I fully expect jumping on the floor. I love that I can visualize these different approaches now after reading through so much feedback on this site! Glad you are all here!
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Re: Ubolts to attach the floor to trailer?

Postby Redneck Packrat » Thu Jun 22, 2017 7:10 am

If you're gonna be off-road (or Illinois :lol: ) then whatever method you choose, be sure to use some sort of lock nuts on your fasteners. Either nylon insert nuts or true "squished" steel locking nuts. Even a split ring lockwasher will vibrate loose over time, and once they become finger tight, it's a matter of a very short time until the nut falls off on the ground.

My floor is WAY overkill, but it's gonna have a power wheelchair doing marromas inside and I don't want the dear wife to fall through and get hung up on a crossmember when she's doing all that turning around :shock: Kinda tough to do all that repair work on the road with her mad at me to boot :lol: Besides, since it's got to be a standie so I can transfer her without throwing my back out, that's two people's worth of weight in one set of foot prints. Also, I wanted lots and lots of weight way down low to resist the sails I'm erecting and calling sidewalls. :thumbsup:
Texas Gulf coast, near Corpus

Working on this, started 5/2017: http://www.tnttt.com/viewtopic.php?t=68614

Some days you're the bug, some days you're the windshield :?
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Re: Ubolts to attach the floor to trailer?

Postby ssuuki19 » Wed Jun 28, 2017 12:30 am

aggie79 wrote:You really don't need much in the way of fasteners to attach the teardrop shell to the frame. I used self-tapping trailer deck screws that go directly into the 2" tube steel frame.

Its funny how many times I have read this on this forum, how you don't need much to secure the shell to the frame, so don't overdo it kindof thing, and I haven't finalized how the shell is going to be secured to the trailer frame for my build yet.

So this post was sortof a funny co-incidence - I researched a lot on this being new to trailers and whatnot. After all the complicated stuff, exhausted at this conundrum, I just hilariously thought the other day that in the end, maybe four 2 dollar, 2" 5/16ths u-bolts from the local store might be one of the best ways, and also inexpensive. Never heard of those t-nuts before, pretty cool especially if they were flat for square tube metal. I think the self tapping screws are under appreciated, in my case the shell is removable so I can't use them, so was thinking perhaps second best choice is generic available everywhere 2" u-bolts.

How does sealant get on my triceps and then my car seat?? more than once??
Aluminum is almost as fascinating as wood.
Link to my build thread: 4 1/2 x 9
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