Constructing a case (rackmount)

[cm961]

I wish to build a 19" rack mount case for my new amp. The design is complete but I'm just wondering how many people have done this successfully? I got some books on metal working from the library and it looks like it can be done fairly easy, but reading about it and doing it are too different things. If I do build the case myself, what kind of material should I use, and where should I get it? The case doesn't have to be super rugged, although the transformer for the PS weighs over 6 kg. Assuming that it can be done, is it cheaper than buying one?

Thanks for any help.

Pete

 

[GRollins]

Pete,
By and large, aluminum is the material of choice for enclosures. Arguments can be made for and against steel. To do a good job, it's nice to have access to proper metal working machinery, such as overhead milling machines. Can it be done without elaborate machinery? Well, yes...sorta. The result usually suits the owner, but no one else. The kind of thing that elicits comments like,"Oh...how...unique!" They're too polite to mention that it looks like the illegitimate offspring of a car wreck and a broken blender.
In theory, you could make a really nice metal enclosure with nothing more than a file, a hand drill, and about 300 man-years of time. In practice, most people flinch when they find out how much the proper machinery costs and opt for buying an enclosure.
There are at least three threads in here about where to find enclosures. One of them is fairly current.

Grey

 

[paulb]

While I gave a couple of links in another thread for purchasing (expensive) enclosures, I tend to be on the cheap side myself.

The latest project I built was a power supply with two quite heavy transformers. I used a black rack panel (Hammond PBPA series) bolted to a standard aluminum chassis and cover (Hammond 1444 and 1434 series - also available in steel, although I agree with Grey's comment that aluminum is better). Then I bought a piece of flat aluminum from a metal supply company and had them bend it into a U shape as a cover (not necessary if you're installing it into a rack). I painted it, but it could be anodized black if you want a really good finish. The bolts through the front can also be black anodized and it all looks reasonably good. I had to use heavy L brackets because of the sheer weight of the transformers mounted on the chassis, but you may not need them if your transformer's not too heavy. You can look at the Hammond parts at http://www.hammondmfg.com .

I noticed a similar approach used by Ken Miller for an amp in his April 2001 Audio Express article. He had the chassis "upside down" (lid up) and mounted all the components inside - he used a toroidal transformer - so no U-shaped lid was needed.

Another thought is to look for a surplus rack mount instrument, tear the guts out of it and replace them. This is what I'm doing for my next project, using a new front panel.

I wouldn't mind hearing about other people's approaches besides buying a readymade expensive enclosure.