A must have reference & data chart book for your workshop. The 28 pages contain data on standardised drill sizes & decimal equivalents, details of all popular threads, tapping & clearance drills, UNF, UNC, BSF, BSW, Metric coarse & fine, hardness comparison tables, jig boring co-ordinates for equally spaced holes, allowances for sheet metal bending & Morse tapers. It also contains tables for sine, cosine, tangents & cotangents. The Zeus Chart fits inside a shirt pocket & with its laminated pages will not pick up dirt, grease or oil.