On Jun 22, 5:16*pm, stryped wrote:
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 “L”
brackets and weld them togther to form a ¼ 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!

Hunh, you got pretty much the exact same reply on s.e.j.w, imagine
that!

If you keep on trying to bull ahead the way you're going despite
getting an aswer you don't like (which your asking the same question
over here strongly implies) then the next answer is this: Doing it
yourself responsibly will take $60-100+k and four years. Professional
liscensure will tack another few years onto that...

You know, maybe $50 or so for a set of plans isn't such a bad idea?
Copying a friend's trailer would cost even less.

But it's pointless, since you'll just go ahead and do it your way
anyway. I don't understand why you insist on asking for advice you
won't follow for every little madcap idea you come up with. Either
listen, or just do it the way you want without asking.

--Glenn Lyford