Brass/bronze sliding on aluminum.....

Is it better or worse than aluminum sliding on aluminum.... hard to imagine it being worse....
In my exercise apparatus folly, I got alum "collars" sliding over sq/rect alum tubes. These are OK, cuz I have nylon as a kind of sliding bearing between the two surfaces..
But the more compact designs have an alum slider *inside* alum channel, with no easy or cost-effective way of utilizing nylon. But mebbe another material, like brass or bronze, would help.
It's a possibility I could make the whole internal assembly out of nylon, which would solve a lot of problems, but for now, another metal that's better than alum on alum would help.
Opinions?

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Usually you do want materials of differing hardness, but it all depends on contact pressure, surface finish, and lubricant. If the contact pressure is not too high and the surfaces well-lubed, Al on Al might work fine. For higher pressures, you might want polished steel or bronze for use on Al.

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DOOD!!!
You done woke me up!!!
I've been laboring under the notion that the "smaller should be softer than the bigger".... iow, the slider, being quite small surface area-wise, should be softer then the much larger tracks that it slides on.
And this is indeed true, all things being equal and esp. if you can finagle nylon "consumables", but in this case, it actually makes quite a bit of sense to just make the slider harder than the long tubes, etc.!! Quite the shift in perspective for me!
Not the optimal situation, but better than what I got now, given that the supports pretty much *must* be made from aluminum -- so far.
And the part is small enough that SS won't break the bank. Altho brass would certainly be easier to work with. And all-nylon would also work really well (frictioally), altho it's hard to get out of the "non-metal" mentality. Props!!

On Thursday, January 24, 2013 2:06:52 AM UTC-8, Existential Angst wrote:
>> >> Is it better or worse than aluminum sliding on aluminum.... hard to
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lum "collars" sliding over sq/rect >> alum tubes. These are OK, cuz I have nylon as a kind of sliding bearing >> between the two surfaces.. >> >> But the more compact designs have an alum slider *inside* alum channel, >> with no easy or cost-effective way of utilizing nylon. But mebbe another >> mat erial, like brass or bronze, would help. >> >> It's a possibility I could m ake the whole internal assembly out of nylon, >> which would solve a lot of problems, but for now, another metal that's >> better than alum on alum wo uld help. >> >> Opinions? >> -- >> EA >> >> > > Usually you do want materia ls of differing hardness, but it all depends on > contact pressure, surface finish, and lubricant. If the contact pressure > is not too high and the s urfaces well-lubed, Al on Al might work fine. For > higher pressures, you m ight want polished steel or bronze for use on Al. > DOOD!!! You done woke m e up!!! I've been laboring under the notion that the "smaller should be sof ter than the bigger".... iow, the slider, being quite small surface area-wi se, should be softer then the much larger tracks that it slides on. And thi s is indeed true, all things being equal and esp. if you can finagle nylon "consumables", but in this case, it actually makes quite a bit of sense to just make the slider harder than the long tubes, etc.!! Quite the shift in perspective for me! Not the optimal situation, but better than what I got n ow, given that the supports pretty much *must* be made from aluminum -- so far. And the part is small enough that SS won't break the bank. Altho brass would certainly be easier to work with. And all-nylon would also work real ly well (frictioally), altho it's hard to get out of the "non-metal" mental ity. Props!! -- EA
No SS against Alum. snowballs will build instantly!!! Think maybe hard ano with teflon on one of the parts, or both, allow the te flon to be the barrier.

You might want to look at having the aluminum anodized with teflon impregnation. No high speed, no high loads. R. Wink
On Wed, 23 Jan 2013 23:04:09 -0500, "Existential Angst"
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Stainless steel (3xx) bears well on aluminum without galling. Brass, not so. Dunno about bronze.
LLoyd