Bolt: hexagon head

ISO 4017

ISO 4017 - Hexagon head screws

Hexagon head screws with metric coarse pitch thread, product grades A and B. The screw is turned by a spanner on a hexagon head and is threaded over its whole length, so one size fits any grip and it can be driven into a tapped hole to any depth; this is the general assembly fastener, used wherever the joint does not need to be clamped on unthreaded metal. The head is the head of ISO 4014 value for value: the thread diameter fixes the width across flats s, the width across corners e, the head height k and the bearing face dw. The thread reaches the head but for the run-out under it, which the standard limits to a max = 3P, so the guaranteed thread length is l - 3P. The length decides the product grade, which is the close grade A up to M24 and 150 mm and the medium grade B beyond either. The range of standard lengths follows a rule instead of a table: from 2d rounded to the nearest nominal length, up to ten diameters and never above 200 mm - a longer joint takes the partially threaded bolt of ISO 4014. Covers threads M1,6 to M64 with nominal lengths 3 to 200 mm. Its German predecessor DIN 933 was replaced by DIN EN ISO 4017, but keeps wider spanner sizes on M10, M12 and M14; the partially threaded counterpart is ISO 4014, the grade C version is ISO 4018 and the fine pitch one is ISO 8676.