K Is for Key Seat

Metalworking Glossary for the Letter K

See the index to the Glossaries here:


  • Kerf. The width of the cut made in a workpiece by a saw blade.
  • Key. The term key can refer to different things related to machine tools, including the T-handle wrench used to secure chucks, an actual key to unlock a mechanism or panel, and a small metal object designed to fit mating slots in two round components, such as a shaft and the hub of a gear mounted on it.
  • Key Seat. A recessed groove machined into either a shaft or a part going on the shaft like a gear. A key will be inserted into the key seat to hold both the shaft and part so that they turn together. A machine designed specifically to cut out such a slot is called a key seater.
  • Knee. The part of a column-type mill that supports the saddle and table. It can be adjusted vertically.
  • Knee Milling Machine. A mill that features an extension from the column called a “knee” that can move the workpiece up and down. It is also called a knee-and-column mill.
  • Knockout. A mechanism to help release a finished forging from a die.
  • Knurling. Generally performed by a lathe, knurling is a process that creates a pattern texture (such as a diamond pattern) into the surface of a workpiece using a roller with many raised spikes. Such textures are useful in creating a handle-type area directly into the workpiece.