Gentlemen: Wanting to build an A Frame crane with fixed feet, non rotational, using 10.750" steel pipe, .500 wall , 40 ft. tall,with a 4 sheave head for 3/4" cable approx. 34 " width at top using 3" solid shaft for sheave support run through both legs and head tied as a unit with 1/4" steel plate boxed around the head of both pipes and legs spread apart at the base of 10ft., two 1" cables will attach tip of boom to a stationary point approx. 70 ft to the rear of boom and the boom operated at a 10 ft radius from bottom of feet. Steel is 36 KSI with a 'K' frame midpoint approx. 15ft down from tip of 8" schedule 40 pipe, all fully welded full penetration. Safety factor of 2 to 1. Can someone tell me what the theoretical capacity would be?

the 70ft distance behind the boom,should have been to the rear fixed tie down point of pendant cables and Sch 40 pipe should be .370 wall thickness, not .500" as indicated. Hopefully I will be able to have at least a 40k load for this setup, if not what wall thickness would be necessary for it or what sized pipe would be required? Thanks for any ideas in this regard.