I want to make a T pad for a air/hyd bottle jack, extending out 24" for a total width of 48" lifting 750# at each end [1/2 total weight of car]. Due to the height of the bottle jack I thought I could use 2"x2" x .250 wall square steel tubing. So I whip out my Machinery Handbook for the strength formulas that I used to use 40 years ago; I might as well been reading Latin, is all Greek to me now. So any one can tell me if the tube I selected is good, bad or ugly ? Or maybe 2.250 round tube with .250 wall or even channel with open end down? Realise that suitable jack and load areas will be made, that I can handle.
So I googled [a lot!] and found some calculators that get you close enough. 2x2x.250 can do the 1500# with only .032 deflection, will do 1800# with .038 deflection and probably 2000# at under .045. 2.500 round with .250 wall will deflect .064, 1800# would be .076..
The Jalopy Journal
