Properly designed undercuts can reduce stress concentrations at the transition point of a fastener. Key Dimensions in the UNI ISO 4755 Table

The standard provides a tabulated set of dimensions in millimeters, which are determined by the and the nominal diameter ( ) of the fastener. Undercut Diameter (

Since the user asked for "Gola" (Groove), it is crucial to distinguish between the and the Thread Run-Out .