You'll refer to this handy pocket reference time and again. It contains: decimal equivalents, USA and metric thread sizes and tap drills, standard drill sizes, USA and metric counterbored holes for cap screws, surface finishes, USA and metric clamping force of standard clamp straps, basic numbering system for steels, machinability comparison of various metals, hardness conversions and tensile strength, metric prefixes, conversion factors for units of measure, and trigonometry calculations (including trigonometry functions, right triangles, and oblique triangles).