Benroy/Cubby Build Sidewall Question

[2bits]

I temporarily used three screws on each side from the outside that went through to the wooden floor (and I wish I didn't because now I have to cover them up) and just used those the whole time I was building, but the galley and other cabinets held it in place too as my walls sit on a groove, so the load was all on the wall, not on the screws. I would find another "placeholder" method though than what I did.


To finalize the deal though, I used aluminum angle with 1/2" screws going into the 3/4" wall, and 3/4" screws going into the thicker floor. Look at the bottom of the pic:

[kennyrayandersen]

Are you saying you didn't even use screws at all to hold the sides on?

That's what I'm saying...but then...

It would certainly keep the walls from separating from the floor (which has been a problem from time to time it seems).

maybe i oughter

Any links to threads discussing this?

I checked and believe it was on some Little Guy’s trailers – there were a couple of threads – one really long one:
http://tnttt.com/viewtopic.php?t=25528
and then this one:
http://tnttt.com/viewtopic.php?t=31185
On the last page mentions the body and sidewall separating.

Thomas has a point – if you bolt from the outside then you have to cover the screw, but I planned on wrapping mine in glass anyway, so that wasn’t a big deal for me. If you had a woody, you could just glue in a plug and flush and finish it – I don’t think it is so big of a deal. And really, you can screw from the floor into the frame as well, you just don’t get the strength of the frame then to help you resist the wall separating from the body that way (lots of people haven’t had trouble with that too).

I think it boils down to whether you used enough fasteners/glue in the first place. The problem was with a commercially produced teardrop, and it was noted that there was a scarcity of fasteners in the joint. If you screw and glue/biscuit or glue/dowel, I’m guessing you aren’t going to have any problems whether you bolt the side wall to the frame anyway, I was just noting that it would definitely eliminate this failure mode and it does make an incredibly strong joint.

[alanv73]

How does this look? If I use 1/4-20 or 5/16-18 carriage bolts, they have a tension strength of something like 60,000PSI, and shear strength 60% of that. Three bolts per side should do it.

[kennyrayandersen]

How does this look? If I use 1/4-20 or 5/16-18 carriage bolts, they have a tension strength of something like 60,000PSI, and shear strength 60% of that. Three bolts per side should do it.

I'm not real sure why you couldn't eliminate the sub floor frame and bolt right to the trailer frame (assuming the trailer frame has the intermediate supports that your floor needs. You could use some construction adhesive to smooth out any low spots. This would save you a couple of inches of interior height and still cover the frame.

It's not really much of a strength issue with the bolts -- just having them is enough. If you can use bolts that have only threads at the end (not all threaded) so the solid shank is in bearing (good design practice).

[Mauleskinner]

I think it boils down to whether you used enough fasteners/glue in the first place. The problem was with a commercially produced teardrop, and it was noted that there was a scarcity of fasteners in the joint. If you screw and glue/biscuit or glue/dowel, I’m guessing you aren’t going to have any problems whether you bolt the side wall to the frame anyway, I was just noting that it would definitely eliminate this failure mode and it does make an incredibly strong joint.

That's probably the case...I've had pretty good luck with thickened epoxy for various applications, but strategically placing some trim with a few lag bolts probably would be good insurance.

You KNOW that if it's gonna come apart, it'll happen at the worst possible time and place.

David

[alanv73]

To make me even more paranoid , I was reading a thread about adding shock absorbers to a TD. Not that I'm considering it for myself, but I just thought it was interesting. There I read some horror stories about the amount of 'bouncing' these TD's do on bumpy roads. All I could picture were those carriage bolts shearing off on my way to my first camp-out.

[Jst83]

Just my thoughts, Why are you going with the 3/4" outside wall I'd go lighter and make it thinner.
Mines held onto the frame with Liquid nails and sheetmetal screws through the 3/4" sheet of plywood into the metal frame and about 6 down each side into the sides. It's 6'6"x11'6", 1,720 lbs and has over 3,500 miles and 3 years on it with no troubles.
Sum it up build light they won't fall apart, I built a tank on wheels and wish I'd have found the forum before I started because there's so much good info here.

[kennyrayandersen]

To make me even more paranoid , I was reading a thread about adding shock absorbers to a TD. Not that I'm considering it for myself, but I just thought it was interesting. There I read some horror stories about the amount of 'bouncing' these TD's do on bumpy roads. All I could picture were those carriage bolts shearing off on my way to my first camp-out.

This is why I'll go with a torsion axle as it not only springs, but damps.
Really though, unless you got some pretty rough roads a regular spring set should work OK.

BTW most of the load is always down, but 3 or 4 lag bolts per side would be HUGELY stiff and strong. The wood would fail long before the bolt does.