Precision Twist Drill Jobber Length Drill Bit, General Purpose Heavy Duty, Series: QC21G, Imperial, #21 Drill - Wire, 0.159 in Drill - Decimal Inch, 3-1/4 in Overall Length, 4XD Cutting Depth, 2 Flutes, Wide Land Parabolic Flute, 2-1/8 in Flute Length, 0.159 in Shank, Straight Shank, 135 deg Point, Split/Self-Centering Point, Right Hand Cutting Direction, HSS Cutting Edge, No Through Coolant, HSS, TiN, Gold, Applicable Materials: Alloy Steel, Aluminum, Aluminum Alloyed, Brass, Bronze, +/-Brass, Copper, Hardened/Tempered Steel, Lamellar Graphite, Magnesium, Magnetic Soft Steel, Plain Carbon Steel, Structural Steel/Case Carburizing Steel and Unalloyed