Din 76a Pdf -

| 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 |

All dimensions are in millimetres. * Scope. This standard specifies dimensions for thread run-outs and thread undercuts for bolts, din 76a pdf

: These are the internal versions (for holes), ensuring a bolt can bottom out completely in a tapped hole. Accessing the Standard | Thread Pitch P | Radius r (min)

) : The curvature radius linking the undercut to the unthreaded shaft to prevent stress risers. Standard DIN 76-A Dimension Table Reference Accessing the Standard ) : The curvature radius