As part of the work of Technical Committee ISO/TC 2, ISO standards for parallel pins and taper pins have been drawn up which necessitated a general revision of existing DIN standards. In that process, a new version of DIN 258 has also been prepared which differs from the issue of March 1961 in the following alterations and additions:
• The diameter 13 mm has been omitted.
• The dimensioning of the thread end has also been altered in conformity with DIN 78, reference being made to this Standard regarding the oval half dog. These alterations do not give rise to any replacement difficulties, because the existing system has, in principle, been retained.
• The nominal lengths l1 and the taper lengths l2 have not been changed, so that here, too, no difficulties arise. However, the tolerance on the nominal length has been altered to js15.
• Detailed technical conditions of delivery based on DIN 267 Part 5 have been incorporated. DIN 7178 Part 1 forms the basis of the tolerances on taper.
• 9 SMnPb 28 K, according to DIN 1651, has been specified as the normal material, but other materials, which are to be agreed, are also permissible.
• When dismantling the pins, difficulties can arise if the larger diameter of the taper has sharp edges. It is therefore recommended either that a small chamfer be made at this point or that the taper be made cylindrical at the edge of the upper part over a length of about 1 mm.
• The designation has been amended to conform to DIN 820 Part 27.