6004153 The orthotest high-precision measuring device which enables measurements to be obtained with an accuracy of .0005 inch (b/w photo) by English Photographer, (20th century); Private Collection; (add.info.: The orthotest high-precision measuring device which enables measurements to be obtained with an accuracy of .0005 inch. It has a scale range of .004 inch on either side of zero and fitted with adjustable limit pointers, Alfred Herbert, Ltd, Coventry. Illustration for Engineering Workshop Practice by Arthur W Judge (new and revised edn, Caxton, c 1936).); by Look and Learn; English, out of copyright.