Drill America Qualtech 21 piece 118 degrees conventional point general purpose drill bit set comes in a metal case. Superhard titanium nitride surface treatment improves drill life, chip ejection, and productivity; decreases horsepower requirements. Ideal for hard metals, work hardened stainless and other difficult to drill materials. High-speed steel tools are good for most general purpose applications, offering a combination of hardness and toughness for wear resistance. Titanium nitride coatings add a hard layer of gold-colored ceramic to the surface that extends tool life and permits faster cutting speeds than uncoated tools. 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 3/8" (1/64 Increments).