Understanding DIN 76-A: The Essential Guide to Thread Undercuts
| Thread Pitch P | Radius r (min) | Width of Undercut g (approx) | Diameter of Undercut d₃ (max) | | :--- | :--- | :--- | :--- | | 0.5 | 0.2 | 1.5 | d - 0.8 | | 0.6 | 0.2 | 1.5 | d - 1.0 | | 0.7 | 0.4 | 2.0 | d - 1.1 | | | 0.4 | 2.0 | d - 1.3 | | 1.0 | 0.6 | 2.5 | d - 1.6 | | 1.25 | 0.6 | 3.0 | d - 2.0 | | 1.5 | 0.8 | 3.5 | d - 2.3 | | 1.75 | 1.0 | 4.0 | d - 2.6 | | 2.0 | 1.0 | 5.0 | d - 3.0 | | 2.5 | 1.2 | 6.0 | d - 3.8 | | 3.0 | 1.6 | 7.0 | d - 4.4 | | 3.5 | 2.0 | 8.0 | d - 5.0 | | 4.0 | 2.0 | 9.0 | d - 5.7 | | 4.5 | 2.5 | 10.0 | d - 6.4 | | 5.0 | 2.5 | 11.0 | d - 7.0 | din 76a pdf
: Specifically for bolts, screws, and similar parts with an external metric thread. Dimensions Understanding DIN 76-A: The Essential Guide to Thread
Released under the full title "Design of thread run-outs and thread undercuts for metric ISO threads according to DIN 13," this standard defines the geometric shapes, dimensions, and tolerances for: It replaces previous versions from 2004 and 1983
If you are looking for mechanical components, you likely mean .
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
