Inspired by smino’s DIY 5 in 3 (5×3.5, 5in3) racks on his mammoth 20-drive build (link to forum post), I decided to do the same. I’ve got a Centurion 590 case, so these will be hidden behind the nice grills.
I had some old 5.5″ hard drive silencers that effectively sandwiched one 3.5″ drive between two pieces of foam inside a 5.5″ steel body. I took the bottom tray and drilled the appropriate holes. You could use the steel from an old CD-ROM/DVD drive (I seem to always have extra DVD drives sitting around). Take a look at smino’s post to get an idea of the variety of things you could use.
I built a template for drilling the holes using the 3.5″ drive specification. I thought others might find this template useful, so here it is below. The lines in the picture are exactly 5.5″ apart, which represent the inside wall of any 5.25″ enclosure.
The discussion around this article can be found here: http://lime-technology.com/forum/index.php?topic=10452.0