Oppervlakteplaat, graniet, 12" x 9" x 2"

Was a bit nervous about flatness after getting burned by cheaper plates before, but this one checked out dead nuts with my old autocollimator. The 2-inch thickness gives it a solid, stable heft that doesn't budge when I'm setting up a dial indicator.

Set a small part flat on this granite and the auto-collimator reading barely moved—dead flat across the whole 12x9 surface. The 2-inch thickness gives it real heft, so it stays put on the bench even during aggressive layout work.

Swapped out my old cast iron plate for this granite one and the difference in stability is night and day. The flatness verified with an auto-collimator gives me confidence when setting up my milling machine.