DIN 186 T-Head bolts with square neck Head Standard Dimensions and Specifications Click the Button to Download DIN 186 Standard Dimensions and Specifications in PDF Format DIN 186 PDF Steel: 4.6, 8.8Stainless: A2,A4 Terminology and Measurements l – Length of Boltd – The Nominal Diameter of the Threadk – Head Heighte – The Diameter of the Circumscribed Circles – Head Widtha1 – Length Undercutdp – Diameter of the Ejectorr – Head Radiusk´ – Minimum Size of the Head on the Keyn – Head Thicknessr1 – Radiusu – Thread Runlg – Length of the Shank to Threadls – Length of the Shank to the Start of the Thread