I have four posts in a square formation. Posts are also square. I want to bolt a beam between two posts on the left and a beam between two posts on the right, and than run some wire between the beams. Beams will be 2.8m long and distance between them will also be 2.8m. They will be 2m above ground. I was thinking a M10 or M12 bolt at each end of the beam. If the wire is right in the middle of beams and is holding 50kg (number taken from a commercial clothesline) what type of beam will be able to support this?
I was considering an angle 50x50x2mm because I can attach it flat to the square post or a 40x20x2mm SHS beam.