Sintered....
is a term for a bronze bushing(and actually other bronze devices) that is porous. In this instance it refers to motor bushings designed to cup a steel shaft end with lubricant.
It's difficult sometimes to tell a impregnated wet bushing from a dry bushing if they are both old in service. As I said, I know of no reliable way to re-impregnate a dry bushing with dry lubricant. Therefore I make them all wet bushings.
In answer to your question, if they are bronze in color or dark bronze, they are sintered bronze bushings. Other than ceramic, you won't see any other type of bushing cup in routine small electric motors. The idea is that the bronze will wears before the steel shaft.
Don't assume that all bronze bushings can be saved and lubricated....some, if run long enough without sufficient lubrication, will have too much play around the shaft. Not the end of the world though because bushings are out there.....although more and more of them are dry impregnated.
Kevin
