Hi,
I am not an engineer but trying to understand bolt strgth, tensile strength og steel and some other varribles for something I am wanting to construct. I am wanting to build a car dolly and/or dual axle trailer. I have welders and have welded on hobby projects but by no means consider myself an expert welder. My idea is to both weld and bolt a square togther to form the frame. I have some 3 inch square tubing laying around, I believe is is 1/8 thick but not sure. It came from some material stand at work that got cut up.
My idea was to get some scrap 1/8 inch plate and torch cut two =93L=94 brackets and weld them togther to form a =BC inch L bracket. These would go on all 4 corners of the square I would bolt each L with bolts through the L and through the 3 inch tubing. Before doing this I would insert a section of black pipe through all pieces for the bolt to ride in. After bolting and everything being square I would weld all joints with 6011 or 6013 rod with either my AC buzzbox or the mIller generator welder I just aquired on DC. (Not welded with it much yet) (I have trouble welding with 7018 for some reason.
My question becomes, what size bolts would be adequate? I get confused when I see specs on bolts such as shear strength, tensile strength, yield strength, etc? I suspect the bolt need only be as strong as the streth of the bolt steel around it. I am having trouble finding the specs for mild steel strength but think it might be around 38,000 PSI? Is this true?
Any help is appreciated!