Starrett 20-3 Square Vintage L.S. STARRETT No. 20 Machinists 3" Hardened Steel Square Tool Athol MASS -- Antique Machinist Square The beams and blades are hardened, ground and lapped to insure parallelism and straightness. 20-3 Master Precision Square Made of high quality tool steel with the finest of craftsmanship throughout. For use when extreme accuracy is required. The beams and the blades are hardened, ground, and lapped to ensure parallelism and straightness. Beam grooved at the inner corner for clearance of burrs or dirt. Made of high quality tool steel, with fine craftsmanship This hardened steel square is used when extreme accuracy is required. 14MA Millimeter Reading Double Steel Square Made of high quality tool steel , Squareness accuracy to 0., 0001 (0., 0025mm) every 6 (150mm)
