Keep It Simple!!!
leafs rock
Thanks guys......... sorted and just when I thought I'd found paydirt.......... Warthogs is the one that 4 wheel drive and sport utility copied shamelessly............
Thread inserts would be good seeing as I'll need 16! .....thanks........................ Looks like I can use 48" upper and lowers............ BUT have ya seen the price of DOM arrrrgggghhhh
Solid bar.mmmnnn....... That'll keep me greasy side down.
Solid bar is weaker!!!!!!
Stiffness is proportional to the inertia moment of the section which is for a circular one J= ∏/32*(D^4-d^4) (for a compression loading in case of a bending 32 becomes 64). Area is A=∏/4*(D^2-d^2). For the same weight the two have same A.If you note d/D=δ the area is A= ∏/4*D^2*(1-δ^2) from which D^2=4*A/(∏*(1-δ^2)) Now the J= ∏/32*D^4*(1-δ^4) = 0.5*A^2/∏*(1-δ^4)/(1-δ^2).Because δ<1 the ratio (1-δ^4)/(1-δ^2) > 1 so that the bigger δ the bigger J for the same A i.e. for same linear weight. There is of course a limit set by the wall buckling.This is the reason why structural tubing has a specific ratio wall/D evn if not under internal pressure.