Yes, they're still in the hall.
Tonight I did a bit of machining and confirmed that I do not have the measuring tools to be able to determine the precision obtainable.
I’ve joked before that if you ever needed a slip-fit, air-tight, bushing – to travel along an elevator shaft – from here to the moon – tell me that it has to be a press-fit.
My hair is about 1.5 thou (0.0015”) thick. Tonight I learned that my starting stock: pieces of 0.750" O.D. x 0.035” wall, that came from the same mill, same extrusion, same lot, *different run*, was out by 0.0002”.
The difference that I can show you is based on how fast air can get past a 0.0002” gap.
The difference that you see as a consumer explains why:
product x costs three times
what product y does.
Does this sound a little bit like: “You get what you pay for”?
Please temper that sales pitch with the question: “What do you need?”
Sometimes having a large amount of resources at your disposal will do more harm than good.
Let us know what you need, want, and can afford;
we will, each and all, respectfully offer our help.
That is how we feed our dependents.