We often marvel that we have to hold tolerances usually higher than even aerospace and still get complaints about micro vibe.
One thing not often recognized is that tolerance costs money. As mentioned before, we have noticed some of our competitors make the tolerance window bigger by expanding it into a tighter bearing post. This saves money because it’s just much easier to hit .001" than it is to hit .0002".
One other little bit of info here is that even our CNC machines have a tolerance (nothing can built perfect). .0001" is the error in the machine. Said another way, we are producing parts on the daily at the maximum accuracy of the machines we own. This is very unusual - even in aerospace.