I am also looking at making the metal cabinet, even if I just stick a picture of the switch gear inside for now.
So I guess the hight measurement of 16 1/4" must include the strap at the bottom. Can I query why you made it 12" and 3" instead of 12 5/8" and 4"? Studying the picture seems to show that the doors have about a 1/2" rounded edge, which would add up to the stated depth of 4 1/2". Can I also ask what thickness of material you are using? I am guessing at something like 12 gauge? So 2 -2.5mm sheet. Regards Ron