With graduated blade only. Double squares are popular with machinists, tools, and pattern makers. Hardened, sliding blades are adjustable for a wide variety of uses. The faces of the head are ground square. 6"/150mm size is equipped with a level, the head is approximately 3-1/2" (90mm) long, and the faces approximately 9/16" (14mm) wide. Blades are graduated in 8ths, 16ths, 32nds, 64ths (1mm both Edges one Side; and 1mm and 1/2mm Reverse Side). Bevel blade has octagon angle at one end and hexagon angle at another end clearly marked. The drill grinding blade is beveled to 59° and 41° and both ends have quick reading machine-divided graduations in 64ths, and graduation is located to measure perpendicularly to the axis of the drill. By reading graduations, the center-point can be easily and accurately located.