Re: [CAD_CAM_EDM_DRO] Re: Brass vs Aluminum

>
> On 3 Nov, gm4ta@... wrote:
> > This may be a little off topic with the main topic of the group, but
> > which is more durable? Brass or aluminum? When I think of aluminum I
> > think of the easy-to-crush pop cans.

if you just need a bracket to hold a part, aluminum is usually fine, much
less expensive than brass, lighter, etc. if you need a lot of
strength, steel is a better choice. Some alloys of aluminum,
in the right temper, can approach the strength of steel, but you
have to know the application and the material very well to
do this reliably.

If there are sliding parts, rotating shafts, etc. aluminum is a poor
choice. Aluminum has abominable lubricating properties, and so
you need to line the aluminum with something to prevent the wear.
Sometimes this is a good approach, a brass or bronze bushing,
or even a plastic bushing for parts getting less frequent use.

Otherwise, it may be best to use a brass part where wear is
expected. Steel shafts running in brass journals perform quite
well (with lube, of course).

Aluminum is not a horrible material. if you know HOW they made
aluminum cans, and that they start with a fairly thick plug of metal
about 1/8" thick, and then smash, bash and squish it until it is in
the shape of a can, with walls only a few thousandths of an inch
thick, you'd be amazed! Cans are essentially pure, elemental
aluminum, which extrudes well, but is not particularly strong.
Aluminum alloys can be had with vastly better material properties
(note most aircraft are close to 100% aluminum alloys) and they
don't fall out of the skies TOO often. There are 40-year old
Cessnas still puttering around, too. Corrosion has to be taken
into account with most metals. Brass is mighty resistant to
corrosion, like in sink drain pipes!

I could babble on for hours, without knowing more about your
application, it wouldn't be of much use to you.

Jon