Exploring some fab houses and I came across this statement from https://www.viapart.com/PCB/Explain
"Minimum slot aperture Mechanical drill 0.6mm The tolerance of groove aperture is±0.1mm"
Does this mean that the smallest hole they can make is ~24mils with an annular ring of ~4mils ? If not, what does Minimum Slot Aperature mean ?
How could one extract annular ring size from their description ?