This International Standard specifies the characteristics of full-length parallel grooved pins made of steel or austenitic stainless steel with chamfer which have three equally spaced grooves impressed longitudinally on their exterior surface and a pilot to facilitate insertion, with nominal diameter, d1, from 1,5 mm to 25 mm inclusive. The displaced material to each side of the grooves forming an expanded diameter d2 which is larger than the nominal diameter d1 will cause a non-positive locking fit when these grooved pins are forced into a drilled hole equal to the nominal diameter d1 (see clause 4).