I'm not judging the fact that the whole instrument was clogged with lime and I couldn't get the valves out of their casings without Herculean efforts. (That's not the fault of the factory at all.)
I'm not judging some of the damage I had to repair.
(Again, the factory didn't damage it, they built it.)
I'm judging the piston to casing fit.
Contact vertical wear lines between the pistons and casings are few and far between.
I didn't buff any of these pistons, I just cleaned them.
There are vertical contact marks only in a few places on each one of the pistons, and not very many around the ports.

