Pickup Truck Flatbed Design
Hello Everyone. Thank you for allowing me to post my questions here.
I have an old one-ton dually pickup truck with a fifth-wheel hitch. It has two steel places mounted in the existing bed which are attached to brackets off the main frame, and which hold the fifth-wheel hitch plate mechanism. It also has a 100 gallon auxiliary aluminum diesel tank in the bed just behind the cab.
The bed is to be replaced with a flatbed design. The framework will lay directly on the existing frame rails or supported just above them to the needed tire clearance height. The two main rails are approximately three foot (3') on center.
In any case, the frame will be created with cross pieces, with similar material boxing it in at the two sides. The spacing between the cross members can be whatever is necessary for proper weight distribution. The bed will be no more than eight feet (8') wide and nine feet (9') long. The framework will be covered by tongue and groove pine boards, laying front to back. The boards will be 1.5" thick. Some additional metal edge trim and details will be added which do not effect the weight or strength.
The idea is to make the truck still carry the 2000 pounds of load rating, but mostly used for the fifth-wheel hitch and toolboxes placed over and under the bed at the sides. The full auxiliary tank adds eight hundred pounds, and tool boxes may add no more than five hundred.
With the current high cost of low carbon steel (mild steel) (A500, A36, ???), it seems wise not to over-build. However, I am at a loss as to which type and configuration to use. Square tube, rectangular tube, C-channel, or whatever. I am hoping to weld it together with my little flux core arc welder, and thought that eighth inch thickness material should be enough and make it easier to weld. And that is about all I know.
Watching videos on YouTube from others who are doing this sort of build leaves me questioning the strength-to-cost benefits of their endeavors.
Does anyone have any ideas to help me calculate the necessary size, shape and thickness trade-offs for my project?
Thank you.