How much variability is there in the thickness of a standard PCB?
Let's say I order a 1.6mm FR-4 board. Will the actual thickness range 1.5mm-1.7mm? 1.4mm-1.8mm? 1.59mm-1.61mm? What is the (approximate) value of x in "1.6mm ± x%"?
What if the board is ordered thinner? (say 0.8mm)
How does controlled impedance affect this range? It's supposed to specify that the dielectric thickness must be controlled, but how much does it actually reduce the variance?
I'm assuming this all varies somewhat by manufacturer, I'm just looking for some reasonable guidelines for what to expect.