Power constant that represents the number of cubic inches of metal per minute that can be removed by one horsepower input.
Glossary
K factor
kerf
Width of cut left after a blade or tool makes a pass.
keyseating
Milling or grinding an internal keyway. See slotting.
killed steel
Steel treated with a strong deoxidizing agent such as silicon or aluminum to reduce the oxygen content so that no reaction occurs between carbon and oxygen during the solidification process.
knockout
Mechanism for releasing workpieces from a die. It is also called ejector, kickout, liftout or shedder.
Knoop hardness number (HK)
Number related to the applied load and to the projected area of the permanent impression made by a rhombic-based pyramidal diamond indenter having included edge angles of 172º 30' and 130º 0'. The Knoop hardness number is the ratio of the applied load (usually, 0.5 kgf and greater) to the projected area of indentation measured in mm2. The area of indentation is proportional to the length of the long diagonal squared and a constant equal to 0.07028.
Knoop hardness test
Test for determining the hardness of a material in which calibrated machines force a rhombic-base pyramidal diamond indenter having specified edge angles into the surface of the material. After the applied load is removed, the length of the long diagonal is measured and the area of indentation is calculated. The result is expressed as the Knoop hardness number. See Brinell hardness test; Rockwell standard hardness test; Rockwell superficial hardness test; Scleroscope hardness test; Vickers hardness test.
knurling
Chipless material-displacement process that is usually accomplished on a lathe by forcing a knurling die into the surface of a rotating workpiece to create a pattern. Knurling is often performed to create a decorative or gripping surface and repair undersized shafts.
knurling tool
Normally a lathe tool for impressing a design on a rod or handle to improve gripping or provide decoration.