Measure with precision using the Draper Engineer\'s Precision Square The Draper Engineer\'s Precision Square is made with solid steel stock with a hardened, tempered and finely polished blade. The squareness of the blade edges and the stock working face falls within ±0.016mm/0.0064\" tolerance. Display packed. Features: Hardened, tempered and finely polish solid steel blade ±0.016mm/0.0064\" Tolerance Specification: Weight: 0.3Kg Tolerance: ±0.016mm/0.0064\" Manufactured to BS 939 Workshop Grade B for squareness tolerance only