: The PDF details the exact upper and lower deviations allowed for the undercut diameter ( ) and width (
If you’re working with ISO metric threads, getting the right is critical for ensuring proper fit and preventing stress concentration at the transition point of a bolt or screw. din 76-a pdf
: Used for external threads (bolts, studs, and shafts) with standard undercut depths. : The PDF details the exact upper and
: Short undercut for external threads, used when space is limited. Forms C & D : The equivalents for internal threads (tapped holes). Why Use Form A? Flush Seating din 76-a pdf
DIN 76-1 categorizes external thread undercuts into different forms based on application requirements: