BS 4168-8 Hexagon Socket Countersunk Head Screws

BS 4168-8 specifies metric hexagon socket countersunk head screws. The drawing shows the flush countersunk head, overall length and hexagon recess.

Technical line drawing of a hexagon socket countersunk head screw with overall length, thread diameter, head diameter, countersink and socket references.

Countersunk screw dimensional reference

Feature	Drawing reference	Measurement
Nominal thread diameter	d	ISO metric thread
Overall length	l	From top of countersunk head to screw end
Head diameter	dk	Countersunk head outer diameter
Head angle	α	Countersink included angle
Socket width	s	Across the hexagon flats
Socket depth	t	Recess depth

Reference note: This is a symbolic reference, not a numeric schedule. The public BSI summary identifies the screw form and dimension scope but does not show the size-by-size values. Use the specified BS 4168-8 edition and gauge requirements for production.