Mechanical Designer is a comprehensive 2D mechanical detailing package. It has thousands of fasteners to BS, ANSI, ISO and DIN standards. Bearings, Circlips etc. Hole features and tabulation, Stepped shaft design, Chain and belt design, geometric and dimensional tolerances, steel sections, weld symbols and much more.
Works with AutoCAD 14 and 2000/2002 (with minor limitations)
At one time Mechanical Designer was the major competitor to Genius (later AutoCAD Mechanical) in the United Kingdom, now it is totally free. Source code available on request.