Having assembled two of the steel cases for the Pi/Digi+ now, I thought it might be useful to others to provide a 'How To Do It' guide.
I know there is a guide here on this site, but it's a little unclear in places and perhaps not so easy to find, as a few others have confirmed to me.
I posted it on my forum The Audio Standard and I hope that it is OK with the admin folks here to link to it.
How to assemble a HiFiBerry metal case for Pi & Digi+
Read more: http://theaudiostandard.net/thread/2319/assemble-hifiberry-metal-case-digi#ixzz4AdN7yE8q