This International Standard specifies the shape and basic dimensions of the hexalobular internal driving
feature for bolts and screws, including the gauging method.
The curvature of the contour of the hexalobular internal driving feature is defined by the gauges specified in
Tables 3, 4 and 5. Additional information which can be used when drawing the contour is given in Annex A.
The intent of this International Standard is to provide the details necessary for inspection of the hexalobular
driving feature. It is not suitable for, nor intended to be used as, a manufacturing standard.