Glossary Terms

Stainless steels possess high strength, heat resistance, excellent workability and erosion resistance. Four general classes have been developed to cover a range of mechanical and physical properties for particular applications.

Relates to the machine tool and is measured in pounds per inch. Static stiffness indicates how many pounds of force it takes to deflect the spindle a linear distance of 1" in a given direction. See dynamic stiffness; stiffness.

Statistical techniques to measure and analyze the extent to which a process deviates from a set standard.

Statistical techniques to measure and improve the quality of a given process.

Supports long, thin or flexible work being turned on a lathe. Mounts on the bed’s ways and, unlike a follower rest, remains at the point where mounted. See follower rest.

Basically, iron in combination with carbon and other elements. There are five major groups of steels: carbon steel, alloy steel, stainless steel, tool steel and maraging steel.

System of numbers developed by the American Iron and Steel Institute and Society of Automotive Engineers to identify steel. The first two digits in the code indicate the family and basic alloying elements. The final two digits indicate the approximate carbon content in hundredths of a percent.

Common method of securing the cutting tool body to the spindle in a machine tool. Comes in various styles, including CAT V-flange, British Taper (BT) and ISO.

Distance between the passes of the toolpath; the path spacing. The distance the tool will move horizontally when making the next pass. Too great of a step-over will cause difficulty machining because there will be too much pressure on the tool as it is trying to cut with too much of its surface area.

1. Ability of a material or part to resist elastic deflection. 2. The rate of stress with respect to strain; the greater the stress required to produce a given strain, the stiffer the material is said to be. See dynamic stiffness; static stiffness.

Cutting fluid that contains no water. Produced from mineral, vegetable, marine or petroleum oils, or combinations of these oils.

NC system wherein tools move at either 45° or 90° angles to the coordinate axes. Used in turning shoulders or milling rectangular shapes; normally is combined with point-to-point system for greater efficiency and flexibility.