This is the popular small pocket booklet that is the reference book for fitters, metal workers and draftsmen. It is printed on stiff card, with a protective plastic coating that makes it very durable for use in the workshop. The tabulated data includes the following: Standard Imperial & metric drill sizes with decimal inch equivalents; thread sizes, tapping drills & clearance drills for to following threads - ISO metric fine, B.S.F., Whitworth, BSP, Unified screw threads, ANC, ANF, ISO metric coarse, UNF, UNC; selected ISO fit hole basis; Hardness comparison table; Equally spaced holes in a circle; allowances for sheet metal bending; morse taper sizes; letter addresses for numerical control; Engineering drawings abbreviations; triangle area and side length calculations; Metric - Imperial conversion tables.