"Richard Smith" wrote in message ...

Great question, but been distracted
("weldsmith" is my site)

New section - "structures"
http://www.weldsmith.co.uk/tech/struct/struct.html

Linking from it -
Three new projects

http://www.weldsmith.co.uk/tech/stru...lyse_test.html
RS
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JSW
I went through a similar process for the frame of the hydraulic bucket
loader I built for my tractor. The square tubing U frame serves as the
hydraulic reservoir so all welds had to be oil-tight as well as strong
enough to withstand the bucket hitting an immovable rock. It did, and the
frame welds held.

To clear the front wheels when turning I had to angle the corners up at 60
degrees from just outside the tractor's frame, then further up, turn another
30 degrees to upright, thus there were four beveled butt joint welds to leak
and more chance of distortion. After welding on the cylinder attachments etc
the top ends bent inward and I had to jack them back to parallel so the boom
pivot pins at the tops of the frame would be in line.

I used a hydraulic pump and cylinder similar to yours, with a
hydraulic-rated tee and a pressure gauge inserted between the pump outlet
and the hose. Afterwards I removed it because the gauge was too susceptible
to damage* if the stiff, springy hose tipped the pump over.

Since the goal was to make both legs parallel I measured the spring-back
from beyond the yield point and jacked the legs that far beyond parallel.
The gauge wasn't much more useful than the feel of the pump handle to
indicate yield.

* These disassemble gauges for repair and recalibration. I made one last
week from scrap 3/8" water pipe.
https://www.amazon.com/SDENSHI-Multi.../dp/B07YX3MJPC
A bag of similar home-made tools got me a job at Segway.
JSW
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RS
Saw that "C3x4.1" is a channel.
We have "PFC" - "Parallel Flange Channel".
That looks like a tapered-thickness flange specification(?)
RS
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JSW
Yes it is, the channels are former pallet rack horizontals from a recycling
company. I assume 36KSI yield for them, unless proof testing shows
otherwise. I didn't measure the force to straighten the bent ones because
the setup made a formidable crossbow as-is and didn't need a projectile.

My question is if you've seen some clever way to splice beams with bolts (or
rivets) without drilling and weakening the tension flange. The pinned fork
joints that connect mobile crane sections might do if there could be enough
clearance underneath for the trolley.