Originally Posted by
Ranko Kohime
On the contrary, wood is very strong. It's no coincidence that the first airplanes were built almost entirely from wood. The trailer I mentioned building is made from 2"x1"X1/16" rectangular tubing, and that stuff is approximately 0.04 lbs. less per linear foot than a 2x4.
Attaching a plywood deck is simple in either method; screw or nail onto a wood frame, use carriage bolts with nuts for steel.
And as for attaching wheels to a wood frame, simply use 4" square steel plates, with milled slots for the axle. (doubled-up junction box covers one finds in the electrical department of hardware stores do nicely for this, in lieu of plate stock)
I tried weighing a chunk of 2x4 I have here and figuring it as an average weight, the frame would weigh about 80lbs.. Plus screws and the wheels(x4). So perhaps 85lbs. A little heavier than I wanted, but far less than I feared. Perhaps if I used a lighter wood for the interior supports I could get that under 70 as most of the weight will be supported by the main beams anyway.