As the name suggests, enables setting of 45 ° mitres. Made to the same specification as the try squares. The stocks are made of Rosewood or Walnut, the blade from tempered, blued steel. They have a machined brass face for protection against damage and accuracy. The blade is secured by means of a brass diamond washer and steel rivet, or all brass round rivets.All try squares are manufactured to BS3322. Each square is tested for accuracy twice during manufacture and again immediately prior to despatch. The squares are tested on both the inside and outside faces, our specification for the internal angle is twice as accurate as that specified in the British Standard, an accuracy better than 0.01mm/10mm blade length.