Bolting floor to trailer question

[slipperyd12]

I was going to bolt my 2x2 wood frame to the trailer with 1/4 inch bolts, Then plywood over the frame. But I got to thinking what if one or more over time vibrate loose? If the head is under my plywood floor it would be that I could not grab the head to hold it while tightning the nut on the bottom. My metal frame is 2x2 3/16. I was going to leave 3/4 for the sides to rest on. So I have 1 1/4 to bolt my wood frame on. Even if I bolted through the top of the plywood the head would still be under the wall. Anyone had ploblems with this or should it be O.K.

Thanks John

[Gerdo]

I would not feel good with 1/4" bolts!!!

[Miriam C.]

John
I used T nuts and ran my 3/8 bolts from the bottom. I have other bolts toward the middle but the ones that are in the way of my wall come up. I put some evil smelling black goo (Gardners roofing) in the hole, using a baggy with the tip cut off. It got messsy but I won. Tip----wear gloves and put paper everywhere. Use old tools.

[Dale M.]

Why not use "Elevator Bolts", they have large flat head that will be even with flooring, and you could use nylon lock nuts or traditional lock washers and nuts to keep them from coming loose...I think the 3/8 size would be appropriate.

http://www.aaronscapscrews.com/ElevatorBolts.htm

Dale

[Micro469]

I still haven't bolted my trailer doown. But I plen to use U Bolts to fasten it down. This would mean i have to groove the top ply to make the u bolt flush with the floor, but when I tighten it down, it will be able to be retightened as necessary. Of course, I can only do this at the trailer cross members....

[bledsoe3]

SD12, You could weld some "tabs" to the inside of the frame like these.

Then use carriage bolts countersunk with nyloc's like this.