2021年2月1日 · This formula works for both metric and imperial units, and for all 60-degree threads (all ISO, DIN, UTS, UNC, UNS, and UNF bolts). The first tap drill chart below is in mm and the next in inches. Both are available as a printable tap drill chart PDF as well. Tap Drill Chart (mm and inches) Drill sizes given are the ‘closest’ drill size ...