I received an e-mail from Woodpeckers offering a limited edition square (http://www.woodpeck.com/1pccarpenter...0&rid=29489241).
They state that they use a feeler gauge to verify that each surface if straight within 0.0015 inch.
This started me wondering, if the 90 degree is off at the top by 0.0015 inch, what is the real angle?
Or better yet, how do you convert between the two?