Bolt Positions

[Forrest747]

I am going to be predrilling the holes to mount before I assemble the frame together. The frame is going to be 5 feet by 10 feet long. The front 2X2 i plan on two holes about a foot from the sides. Than on the sides I was thinking one hole every two feet in between the cross members and then the same configuration for the rear bumper two holes about one foot from the sides. This is for mounting the floor of the trailer to the frame.

Any suggestions? Am i on the correct path?

[kennyrayandersen]

Maybe pre-drill the frame and then once the cabin is on drill the hole trough the wood (or at least mark them for drilling.

I would be afraid of misaligning the hole and having to drill more (or again) anyway.

As for numbers, virtually the entire load is down, and you floor is probably attached to the sides anyway and the floor rides right on the frame, so there isn’t much load going through the bolts anyway. Every couple of feet is probably fine.

[mikeschn]

Don't predrill. The holes won't line up.

You can drill thru the frame into the body... or thru the floor, into the chassis. The latter is what I do.

The load that we are concerned with here is the forward and aft load, the one that would tend to shear the bolts. Make sure your bolts are big enough... 3/8" seems to be pretty good. And make sure you have enough of them to handle an abusive stop. 4 or 5 on a side should do it.

Andrew, any more thoughts?

Mike...

[Forrest747]

I am powdercoating the frame and thought having the holes predrilled in the chassis will help fight the rust.

I am using 3/8 inch bolts to hold it down. I am going to build the floor once the chassis is done to match up and then drill thru the frame into the floor.

Thanks for the advice

[angib]

I would agree that some 3/8" bolts either side would be enough. There seem to have been some trailers with very few rusty bolts or screws holding the body on - and yet the body hasn't come off. I certainly don't see any advantage in huge bolts, as they will be stronger than the floor.

I think that really the bolts/screws just hold the floor in contact with the frame, and that friction between the floor and the frame does more to hold the body in place than shear in the bolts.

If you're powdercoating, be sure to drill the holes in the frame big 7/16" for 3/8" bolts?), so that you don't remove all the powdercoating when drilling the holes through the floor afterwards.

Andrew