Hard and soft metals

[Xaccers]

I was told when I was young that if a hard and soft metal are rubbing together, the soft metal will wear down the hard one.
Is that actually the case?

[MikeT]

I think they will both wear, just the hard metal will resist more than the softer metal so I don't understand that principle at all.

Therefore, using copper to scrape a cylinder head mating surface CAN damage the harder alloy etc

[goldfinche]

Hello all. I am afraid I cant be a great deal of help and can only confirm that something soft can wear out a steel shaft. To the extent that an oil seal made of 'rubber' ( OK I know it's not rubber as such.) can wear a groove into a steel shaft so much that even with a new seal it will leak, an example being a camshaft seal on an xud. Certainly bronze bushes can 'destroy' a steel shaft. I to would be more than interested to know why, somebody must know. Anders???
Cheers.
Geoff.

[James.UK]

Most solid bearings are made of soft metals, that way they wear out first and can be replaced..

As a lad, I replaced dozens of white metal big end shell bearings but never had to have the crankshafts reground. and they used phosphor bronze sleeves in the bores of oxygen compressors when I worked on them.. Sooo......

No.. The soft metal will always wear out first.
.