Drill America - Kfd15J-Set 15 Piece Heavy Duty High Speed Steel, Kfd Series Drill America KFD 15 piece 135 degrees split point heavy duty drill bit set comes in a metal case. Manufactured from premium grade High-Speed Steel, Killer Force Drills have a heavy duty 135 split point for self-centering and reducing thrust. Gold and black surface treated for use in stainless steel and other hard metal drilling. High-speed steel tools are good for most general purpose applications, offering a combination of hardness and toughness for wear resistance. Black oxide treatment adds lubricity and creates small pockets on the surface of the tool that act to hold coolant near the cutting edge. Round shanks allow use with a wide variety of toolholding systems. When run in a counterclockwise direction (right-hand cut) spiral fluted tools evacuate chips up and out of the cut to reduce clogging. Set include fractional sizes: 1/16" to 1/2" (1/32 Increments). High-speed steel tools are good for most general purpose applications, offering a combination of hardness and toughness for wear resistance Black oxide treatment adds lubricity and creates small pockets on the surface of the tool that act to hold coolant near the cutting edge Round shanks allow use with a wide variety of toolholding systems When run in a counterclockwise direction (right-hand cut) spiral fluted tools evacuate chips up and out of the cut to reduce clogging 15 piece drill bit set comes in a metal case