Review on 6" X 18" A Grade Granite Surface Plate - Perfect For Precision Measurement! by Kendrick Barron

It comes with a 25 point report from the factory verifying tolerance. According to the report, it has a 2.7 crown to it. That's in MICRONS. That works out to about 0.00001" the stated tolerance on the item is 0.00005". I have no way to verify these figures, but I have already check my (cheap) straight edge which has a stated tolerance of 0.003". It was checking out at under 0.002". I just work on wood, and this is good enough for me. This will serve as the baseline for all of my tooling in the shop. I bought it to sharpen my 12" joiner knives, and as an installation jig. I will be using it to verify all sorts of stuff, as I already have started to. I am a big fan of precision, and this gets my vote.