Physical description

Cardboard image chart covered in clear plastic showing a variety of black and white photomicrographs, measurements and images: - curve indicating condition of screw prior to regrinding - curves showing progressive improvement during regrinding - curve showing result of corrections. - general view of Apparatus for cutting ratchet teeth. - apparatus for refining crudely separated abrasive - photomicrographs of Abrasives used in lapping the lead screw - photomicrographs of Grayson’s test rulings (Approx. 1875) - Diamond Carriage Front View - Plan of Apparatus for testing the screw - Measurements of Grayson’s Test Rulings