An extremely handy pocket sized reference booklet of data charts & tables for the drawing office toolroom or workshop. This metric revision publication is produced by Zeus Precision Charts Ltd who are members of the British Standards Institution. The 28 laminated pages contain data on standard drill sizes & decimal equivalents, tapping drills & clearances for metric & imperial threads, BS4500 tolerances, hardeners comparisons, jig boring co-ordinates for equally spaced holes, allowances for sheet metal bending & Morse tapers. Also long tables for sine, cosine, tangents & cotangent.