Owel
I built the rack frame from 3mm aluminium angle, it was the only way to get the dimensions right. This is a mother of a box 23kgs, 345mm deep, 8 units high!
Tools of trade, hacksaw, centre punch and drill-press and lots of time, about 16 hours to build the case, mount the backplane and punch out the rear panel. All panels are mounted with tapped holes into the frame, so they can all be easily removed.
The cream coloured strips lock in the channel modules, which plug into the backplane, being light coloured it can be used as a "scribble strip".
Tips: measure, check, measure again, go have a coffee and fag, check again, think about what you have forgotten to take into account, measure again...get more aluminium, 'cause you stuffed up, start over again!!