Ainjest High Speed Screwcutting - High Speed Threading Attachment. Detailed Instruction Manual and Spares Parts Manual as Exploded Parts Diagrams. Covers how to operate on all on models as used on a variety of Colchester, Harrison and other makes of lathe. Both the dial-selector and lever-selector models are covered - though not all styles of body casting are shown - these varying with the particular machine to which they were fitted.