On Jan 2, 2016, Ed Huntress wrote
(in ):

On Sat, 2 Jan 2016 11:44:17 -0800 (PST),
wrote:

On Sunday, August 16, 2015 at 11:05:10 PM UTC-7, Tom Gardner wrote:
On 8/16/2015 1:30 AM, Gunner Asch wrote:

I should mention that Ive turned rough pure silver rods into bullets
on CNC lathes.

They dont cast well

I turn some also, they cut as nice as AL. They cast fine ... if you
have the stuff.

Pure silver cannot be melted in an oxygen atmosphere, or it
cracks (due to dissolved gas release) on solidification. That's why
sterling silver contains copper- the alloy is better behaved.

Interestingly, some high-performance bearings, instead of Babbitt metal,
have been made of silver. It may be hard, but it's apparently nice and
slippery.

This may not be what you're referring to, but steel roller bearings
used in gas turbines often are silver-plated. The purpose it twofold:
it makes a superior bearing surface in normal operation (why, I don't
know), and it offers some protection in case the oil supply is
temporarily blocked. Like cast iron or babbitt, it provides some
lubrication even when run dry.

The silver prevents galling. If I recall, this was discovered in the 1960s by
NASA, who needed bearings that would work in hard vacuum. I recall reading a
number of Tech Briefs on the subject.

Joe Gwinn