: The specific rounding radii defined in the DIN 76 PDF technical tables reduce stress peaks at the transition point between the thread and the bolt shank.
The fastener can be tightened completely against the part. din 76a pdf
: DIN 76-1 isn't just about fit; it's about safety. Form A specifies a specific radius ( : The specific rounding radii defined in the
: Specifically used for external threads (bolts/screws) where a "normal" undercut depth and width are required. Dimensions defined : : The diameter of the undercut (the "groove" diameter). : The width of the undercut. Form A specifies a specific radius ( :
: The radius of the transition between the shank and the undercut. Standard Dimensions (Metric ISO Threads)
: While DIN 76A is "normal," there are also "short" (B) and "long" (C) versions depending on the required clearance and material strength. Related Standards in the DIN 76 Series
DIN 76-1 (Form A) specifies dimensions for thread undercuts and run-outs on external metric threads to allow components to seat flush against a shoulder. The standard defines specific undercut diameters, widths, and radii based on the thread pitch to ensure proper assembly for standard requirements. The official technical documentation can be acquired through DIN Media or Beuth Verlag.