Compared with the April 1956 issue, the following amendments and additions should be noted:
a) In agreement with the international selection of threads for screws and bolts, the sizes M 1.6, M 1.9 and M 2.5 have been included. The sizes M 1.7, M 2.3 and M 2.6 have been barred for new designs.
b) Sizes over M 10 have been deleted because in this range set screws with hexagon socket according to DIN 913 provide better tightening facilities.
c) In agreement with ISO Recommendation R 888 and the new screws and bolts standards already issued, the 15 mm nominal length has been superceded by 14 and 16 mm, the 16 mn length being preferred. The reference to intermediate lengths, however, continues to provide the possibility of ordering the 15 mm length according to this Standard in cases where it cannot be replaced by the 16 mm.
d) Some of the slot dimensions have been altered and brought into line with the provisions of DIN 267 Part 2. The slot depths have been corrected to make the minimum depth 2.5 x thread pitch.
e) The oval form previously given to the slotted end has been replaced by a chamfered end. The chamfered end provides better tightening facilities and is also more satisfactory from the production standpoint.
f) The content of the Standard has undergone re-editing.