In mechanical engineering and precision manufacturing, the proper termination of a screw thread is critical to the structural integrity and successful assembly of components. When a bolt or screw is threaded close to a shoulder or a bearing face, a geometric transition is required so that the mating part can seat perfectly flush. This geometric feature is standardized under the German industrial norm .
: Fasteners with a thread undercut do not meet the minimum breaking load requirements specified in DIN EN ISO 898-1 Accessing the PDF and Papers
For metric ISO threads (DIN 13-1), the dimensions are calculated relative to the thread pitch ( Design Type Dimension Calculation (Approx.) Undercut Width ( Normal (Form A) Undercut Width ( Short (Form B) Undercut Diameter ( External Thread Less than the thread's minor diameter Undercut Diameter ( Internal Thread Greater than the thread's nominal diameter Versions and Document Access The most current version of this standard is DIN 76-1:2016-08 . It replaces previous versions from 2004 and 1983. Official PDF
Din 76a: Pdf [cracked]
In mechanical engineering and precision manufacturing, the proper termination of a screw thread is critical to the structural integrity and successful assembly of components. When a bolt or screw is threaded close to a shoulder or a bearing face, a geometric transition is required so that the mating part can seat perfectly flush. This geometric feature is standardized under the German industrial norm .
: Fasteners with a thread undercut do not meet the minimum breaking load requirements specified in DIN EN ISO 898-1 Accessing the PDF and Papers din 76a pdf
For metric ISO threads (DIN 13-1), the dimensions are calculated relative to the thread pitch ( Design Type Dimension Calculation (Approx.) Undercut Width ( Normal (Form A) Undercut Width ( Short (Form B) Undercut Diameter ( External Thread Less than the thread's minor diameter Undercut Diameter ( Internal Thread Greater than the thread's nominal diameter Versions and Document Access The most current version of this standard is DIN 76-1:2016-08 . It replaces previous versions from 2004 and 1983. Official PDF : Fasteners with a thread undercut do not
