brake drum section

Nice section, nice snapshot.

Bears no relationship to a drum after 10 or 15 years of driving in Chicago, Milwaukee, Minneapolis etc

The work certainly bares all the "sophistication" and "expertise" of what one might expect from a slow-witted, middle school, shop class student whose test scores exposed the fact that he couldn't begin to merit inclusion into a science curriculum.

lol People can "test OUT" of Science classes where you live? I hope the Ditch Diggers Union recruits there! GW

true, you will see a good deal more pitting and oxidation, /but/ the principle remains the same - it's just a matter of degree.

this drum was actually fairly rusty for kalifornistan, but the vehicle was originally from out of state...

"Where I live", testing-OUT of a class equates to demonstrating knowledge of the subject material being taught prior to enrollment, which is the opposite of your inferrence. But if that's the intent you parsed from my above sentence, you may require remedial english.

Are you aware that in a high rust environment, all the surfaces rust? This includes the surfaces that make contact with the shoes. The rust is continuously removed by the use of the brakes.

You should see the amount of wear on the brake drums of amphibious vehicles.

i used to live in "the belt" and am more than familiar with its consequences - thanks for checking. i also have this component in my possession so i'm a bit more aware of its overall condition than you.

Uneven wear across the width. That might indicate the actual root cause better than jumping immediately to one's own biases.

Nothing was said about any component in your possession.

If the brake drum is exposed to corrosive environment the shoes will wear into the drum faster than when the drum lives in an environment where little rust forms. The same thing happens if the vehicle is driven off-road or on gravel roads when grit gets between drum and shoes. That type of wear occurs regardless of what material is used for brake lining.

Supporting that would be the wear pattern shown. More wear towards the point where grit and moisture would enter the drum.