Attaching trailer to frame

[greygoos]

I was only making a suggestion and repeating what I have been told by family members in the fastener business for more than 50 years. Please accept my apology if I have offended anyone or given out the wrong information.

Elevator bolts were put into production for exactly that, elevators. They were used for grain elevators and were manufactured to snap with stress.

Well then apparently Uhaul made a major manufacturing error. Which type stress were they designed to fail at, shear or tensile. I'll pass that info on to all the Uhaul owners that they are using the wrong bolts.

[GPW]

If you’re in doubt , just use MORE bolts !!!

[mary and bob]

Actually Jim I did a little research and found you are mostly correct. Using info on McMaster Carr website a standard elevator bolt, 1/4" 5/16, and 3/8 has tensile strength of 70,000 psi. Same sizes, grade 5 carriage bolts have a tensile strength of 120,000 psi. Stainless steel carriage bolts in those sizes are rated at 70,000 psi. My understanding on the elevator bolts is the large flat head is the key design, to spread the load and have no protrusion above a belt, or in the Uhaul case, above the floor in the walk area. I've also heard, but didn't confirm, that Airstream uses them to attach the floor to the frame. So if anyone is concerned that 70,000 psi is not enough, then definitely go with the carriage bolts. For what it's worth, there has been no known body / frame separation on any Uhaul campers, even one that was rear ended by a big truck.

[Ottsville]

So if anyone is concerned that 70,000 psi is not enough, then definitely go with the carriage bolts.

70k psi is what the most common welding wires are rated at, so those bolts are theoretically as strong as the welds on your trailer.

[tony.latham]

Ooooooo pretty.

She's sheathed in silver.





Tony

[NorthEGPhoto]

I used 2x2 Brown pressure treated wood bolted with flush carriage bolts (zinc coated) to the metal frame, and then just used many, many, screws to attach everything else to that.