The Precision Twist 1290 jobber drill bit is a conventional point, general-purpose, round shank drill bit made of HSS with an uncoated finish. It is suitable for drilling to a depth up to 12 times the diameter of the drill. Good for portable or machine drilling. The shank diameter is the same as the drill size. It was designed for drilling holes into a wide variety of metals and synthetic materials.
The 1290 series has a type N flute form, with a regular helix angle of 21 to 34 degrees, have best performance drilling into steel or cast iron.The uncoated finish helps keep costs down, yet provides acceptable performance in most situations. The finish helps increase chip flow in soft materials. Spiral flutes act as a passageway for chip extraction from the hole and for coolant to enter the hole. Right-hand twist brings chips up and away from the cutting edge. The extra length allows for more freedom in being able to drill a wider variety of circumstances.
and away from the cutting edge. They are made to DIN 338 industry standards, which ensure that drill bits around the world conform to the same specifications.