Richard submitted this idea :
I'm (fairly) good at sticking bits of trailer together with my MIG but have
never built anything from scratch.

Friend wants me to build him a light duty security door which will allow him
to prop the main door to an underground building open so as to allow
increased air flow but which exclude unwanted visitors. I guess that he
envisages something like a tennis court gate but with expanded sheet steel in
place of the chain link netting.

So, to the questions. Assuming that I make the frame and door from RSA
steel, how do ensure that everything stays flat and square as I weld it up?
Do I need more/fewer/different braces? How do I attach hinges and locks?
Any pointers to plans/instuctions on the web would be much appreciated.

Depending upon the accuracy needed, it needs to be laid out on a good
flat surface and either clamped or weighted down so it doesn't move.
Then make several tack welds around the various bits, before
progressing on to the full weld runs.

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Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk