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Steel or Aluminum Chassis?

4/28/2000 5:01 AM
Steel or Aluminum Chassis?
I'm looking through the Hammond line of chassis and trying to decide which to get. Obviously the aluminum will be easier to drill and punch, and the steel will be sturdier, but what are to other pros and cons?
4/30/2000 9:37 AM

Steel stands up to physical abuse better than aluminum, such as the weight of transformers, but unless it's protected against rust, will, in time. It's also a lot harder on drill bits, punches, etc. Aluminum is less harder on the drills, etc.  
My main points, IMHO, is that for "small" stuff like stomp boxes, aluminum is the way to go, for an amp chassis, steel. YMMV. If you do go to alumium for an amp chassis, you might want to cut some steel "support" plates to stick under the trannys.  
4/30/2000 4:36 PM
Don Symes

Mr Mann makes an excellent point - how heavy are your transformers, and how big is the box?
4/30/2000 5:20 PM
Ray Ivers

From everything I've read over the years, a thick aluminum chassis is probably what I'd use. There are oxidation and strength issues (THICK!), but aluminum has the advantages of a) not being magnetic and spreading the power transformer's noise all over the place and b) being a better conductor than steel, making ground loop voltage drops lower than steel. As you mentioned, it's also much easier to work with than steel. Heavy items such as transformers should probably be placed close to the chassis edge for support. Aluminum can also be anodized for corrosion-proofing, but then you'll have to grind your grounds.  
THICK aluminum! - are the Hammond chassis thick? My Antique Electronics catalog doesn't say.  
Ray Ivers
4/30/2000 6:36 PM

.040" to .050" is the norm for those "over the counter" chassis', Ray.  
BTW.. what is the plural for more then one chassis?  
.040" to .050" is fine for 5w to 20w amps or for prototype or homebrew use but not for serious retail amp building.  
I use .080" Aluminum with all welded corners for mine and they are anodized in clear or black.  
Our metal candy apple reddish anodizing is particularly handsome.  
Mounting the trannies close to the ends, is the ticket.  
4/30/2000 8:00 PM
Ray Ivers

Thanks for the thickness info (or should I say "thinness info"). Unless you plan to use internal bracing and lots of big washers on your components, that ain't gonna cut it at all for an amp that probably will have it's share of drops and knocks - even without that, there's the sag factor... Does anyone know of thicker aluminum chassises? (How's that, Bruce? - at least I get to build my own words, and lack of thickness is never a problem with me).  
Clear and candy-apple anodizing? Cool!  
Also, thanks for the Magic Parts url. I love the way Alphas feel, and I can't wait to order some.  
4/30/2000 10:32 PM
Eric H

"BTW.. what is the plural for more then one chassis?"
chassis --only the pronunciation changes.  
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