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H-Frame Press - weld or bolt?

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hopefuldave:
Thanks Lew!
I've been scrupulous about sticking to the same units (mm and Newtons) throughout, so I guess my results should hold true - I think the channel may be the bastard offspring of US and Chinese standards, as the web thickness is 4mm, about 160 thousandths rather than 248, which puts it at about C4 x 5.4... But thinner walls and broader flanges...  This may explain the unexpectedly low deflection I got, it's stiff (high section modulus) but not strong, as using a single beam with the web vertical it isn't *quite* at the elastic limit at the projected load!
I think I'll definitely double up on the crossbeams, probably weld in some braces between the flanges to prevent buckling, and bolt it up with strategic crush tubes - I may sacrifice some convenience for strength by making the "work" beam bolted rather than sat on cross-pins.

Thanks again,
Dave H. (the other one)

Lew_Merrick_PE:
Dave,

Yeah, I have seen major corporations having to deal with Chinese versions of standards.  I sat and watched as supposedly ASTM A569 low carbon sheet steel broke when folding a hem.  My spark test analysis suggested that the steel had somewhere in the 0.55% carbon content (and actual tests later confirmed it was an 1158 type of steel).  Until you have seen what passes for certificates of compliance from Chinese steel mills, you don't know what satire is!

Chinese industry cannot be as bad across the board as my (roughly) 3 dozen experiences suggest.  But I cannot say that I have ever had a good experience when dealing with major corporate outsourcing to China operations.

hopefuldave:
That's the joy of Standards, so many to choose from... Or to ignore.
I think your impression based on experience is about 105% accurate - I'm really not a fan of Chinese "engineering", seen too many imported machines etc that haven't even tried to meet basic safety standards and had to put 'em right... As for machine inspection reports with the handwritten measurements printed along with the form...

Dave H. (the other one)

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