METRO Engineering Try Square 4" Heavy Duty Tri-Square  (Pack of 1)

The engineers try-square is composed of two parts, the stock and the blade. They are usually made from bright mild steel with the blade being hardened and tempered so that it resists damage. A typical use of an engineers try-square is to mark out material for cutting/shaping. A machinist square or engineer's square is the metalworkers' equivalent of a try square. It consists of a steel blade inserted and either welded or pinned into a heavier body at an angle of 90°. ... This prevents small particles from accumulating at the juncture and affecting the square's reading.