BS 4168-6 Hexagon Socket Button Head Screws

BS 4168-6 specifies hexagon socket button head screws with ISO metric threads. BSI gives a nominal thread range from 3 mm through 16 mm and notes that this part is not equivalent to ISO 7380.

Technical line drawing of a hexagon socket button head screw with length, thread diameter, head diameter, head height and socket references.

Dimensional reference

FeatureDrawing referenceScope / measurement
Nominal thread diameterdMetric sizes M3 through M16 in the BSI summary
Screw lengthlMeasured from bearing face to end
Button head diameterdkSize-specific maximum and minimum
Button head heightkSize-specific head profile
Hexagon socket widthsAcross flats
Socket depthtSize-specific minimum depth

Reference note: The public BSI record provides the metric size range but not the complete numeric dimension schedule. BS 4168-6 is not equivalent to ISO 7380, so no ISO 7380 values have been substituted. Use the exact BS 4168-6 schedule for numeric limits.