Hello, i read the whole thread.... But what if i was trying to build a
crane over a job site and had a similar idea using the same materials?
How could i improve it?... Big factors to keep in mind are portability
(easy setup and take down), least weight vs. Highest strength of steel
piping, safety, and lowest possible cost.
This column calculator takes pipe 2" and up:
"Pinned at both ends" means the load is applied directly in line with
the pipe, without sideways force that tends to bow it. That restricts
your design considerably, all the commercial hoists I've studied apply
a cantilevered load to the columns which requires more complex
W sections are better than pipe for the bending loads on horizontal
It's possible to build a portable gantry crane with a simple geometry
that uses only pinned- or ball-end columns but I can't prove the
safety of my design and won't describe it. I test everything for
deflection with a measured proof load, and sometimes find unexpected
weakness or bad material.