On 7 Dec 2003 08:23:15 -0800, (noel) wrote:
I want to build a couple of pc cases and a few trays. The
front/back panels I will probably have done on a cnc machine. And the
top/side cover I'll probably have done by a shop. What I will want to
build is the base/internal box and support structures for the mother
board, drives, power supply, and such.
snip
So, I guess I need a suggestion as to:
1. What material and at what thickness do I need to use?
2. A means of cutting this material safely and cheaply?

The structures you're talking about are normally sheared and
brake bent. So you need a bench shear to cut the material,
and a bench brake to bend it.

Not highly recommended for heavy use, but Harbor Freight sells
a 30 inch shear/brake/roll combo machine which would suffice for
this project. It is much cheaper than anything else you could find
which could handle the job (currently on sale for about $270).

Most of the case makers use sheet steel for the substructure,
I would too. It doesn't carry a lot of load, so it doesn't have to
be very thick. 20 gage would be fine, 18 gage is probably overkill.
The bends, and sometimes beads, give it the required stiffness.

Note, if you don't care if it looks like a conventional PC, you could
use rack and panel construction. That can be done with ordinary
hand tools (ie hacksaw, hand drill, etc).

As a final note, case design is not a trivial exercise. Computer
cases go through an elaborate thermal design process to make
sure the electronics doesn't suffer from hot spots in the case due
to stagnated air flows. There are also EMI/RFI considerations.
So if you are trying for a conventional PC case, follow a proven
design very carefully. Even small deviations from the design can
cause radically different internal air flows.

Gary