1/4-20 unc drill size in mm 793911-Drill size for 1/4 unc thread
The DORMER 1/4 UNC, mm OAL, 047" Drill Diam x 13mm Drill Length, Combination Drill & Tap 2 Flutes, 17mm Thread Length, High Speed Steel, Oxide Finish, 2B can be found within the Combination Drill & Taps category As part of MSC Industrial Supply's Threading offering, this item can be found using MSC part numberTHREAD/SCREW Drill & Tap Chart Machine Screw Size Threads Per Inch Minor Dia Tap Drills Clearance Hole Drills Alum, Brass, & Plasitcs 75% Thread Stainless Steel, Steels & Iron 50% Thread All Materials Close Fit Free Fit # or Dia Major Dia Drill Size Decimal Equiv Drill Size Decimal Equiv Drill Size Decimal Equiv Drill Size Decimal EquivAs a rule of thumb, for Metric threads, the tapping drill can be calculated by subtracting the pitch from the diameter of the thread eg for an M5x075 thread the tapping drill is 5075mm = 425mm For Imperial (inch) threads the tapping drill size is calculated in the same way, diameter minus pitch eg for 3/410 UNC pitch = 0