joining metal plate

[zedman]

Hi,
I want to make a joint between:
a: metal plate thicknes: 5 mm to a hollow section 50x50x3.2
b) metal plate thickness: 5mm to a metal plate 12 mm thickness.
what is the size of the bolt that suits these joint or should I weld it? tq.

 

[MadMango]

There's not enough information provided to give you a proper answer.

What loads/forces are involved?
What dynamics are at play with the joint?
Ect, ect.

MadMango
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