This 3rd edition of DIN Handbook 193 contains 38 fundamental standards on fasteners, covering such areas as countersinks and counterbores, widths across flats, thread run-outs and thread undercuts, bolt and screw ends, stud ends and tapped holes for compression couplings, driving features, tolerances for screw threads and nomenclature. New to this compilation are DIN 34824 dealing with 12 point sockets for bolts and screws and DIN EN ISO 15065 which reflects current practice in Europe with regard to countersinks for countersunk head screws. Also included for the first time is DIN EN ISO 225 “Fasteners – Bolts, screws, studs and nuts – Symbols and descriptions of dimensions” which, together with DIN ISO 1891, now also incorporates terminology in Chinese, Japanese and Swedish. Four standards have been revised for this edition, among them DIN 918 Supplement 3 which provides information on the current status of European standardization relating to fasteners. DIN Handbook 193 is one of a series of six handbooks on fasteners (DIN Handbooks 10, 43, 55, 140, 193 and 362). Standards on threads for general and special applications are compiled in DIN Handbook 45 (“Threads for engineering”, 1st edition 2009) – the ideal complement to the fasteners handbook series. The standards in this edition are the versions current as of March 2011.