"Joseph Gwinn" wrote
Ignoramus13761 wrote:

In any case, I think, if he wants to go ahead, he should, it is his
right, but he should test the crane at his planned capacity, very
carefully.

At capacity? Not even close. Test at about four times stated capacity.
No matter how good an engineer/welder one may be.

Joe Gwinn

The recommendation I've seen is to load a qualification test sample to 4X
but proof the identical working model(s) to 2X. For example 3/8" Grade 70
chain has a WLL 0f 6600 Lbs, proof test of 13,200 and minimum breaking force
of 26,400.
http://www.nacm.info/Downloads/NACM%20_Welded_Specs.pdf

But first you need a load cell. Mine, from an auction, was still expensive
at 5% of list price. The dial indicator readout makes it almost too fragile
to survive field use. Do NOT ask to borrow it.

HF seems to have discontinued the 440 Lb Big Game Scale. Maybe you could
rework the sensors and display from a bathroom scale???

jsw