Abstract: A method and apparatus for determining the degree of alignment or misalignment of various web offset lithograph printing press components is disclosed. An alignment block is provided having one surface with a modified curved "v" contour, and with a plurality of receptacles for holding register measuring components. The remaining sides of the alignment block are planar and mutually perpendicular. Register measuring components can be attached to extensions placed within the receptacles and those register measuring components are used to measure deviation of web offset press components from a reference point in the press. The alignment block is adaptable to receive dowel pins in the receptacles, which form a corner with the blocks that can be simply and easily placed upon a precisely positioned reference positions on the frame of a color unit of a web offset press.