There is an article in the November/December 2000 issue of Wooden Boat by the eminent planer Aime Fraser. Interesting, she explains that a low-angle block plane actually has a higher cutting angle than a standard bench plane. The reasoning is that a block plane is used with the blade bevel up, so that the cutting angle is the sum of the blade angle in the plane and the angle of the sharpened bevel. In a bench plane the bevel is down, so the cutting angle is equal to the angle of the blade in the plane.