Glossary Terms

3-D model created using “building blocks.” This is the most accurate way of representing real-world objects in CAD.

Fluid in which oil is suspended in water. Because water is a superior heat-removal agent, this fluid is primarily used when lubrication is desirable but cooling is the key consideration. The ratio of oils and other additives to water varies with the application.

Flat end-cutting tool used to produce holes ranging from about 1" to 6" in diameter. Spade drills consist of an interchangeable cutting blade and a toolholder that has a slot into which the blade fits. In horizontal applications, universal spade drills can achieve extreme depth-to-diameter ratios, but, in vertical applications, the tools are limited by poor chip evacuation.

Drilling operation in which a machine powers a cutting tool consisting of a holder and flat, interchangeable end-cutting blades. Spade drilling takes over where twist drilling leaves off; requires more power and a larger machine but offers lower cost and greater rigidity. Large-diameter spade drills are used when trepanning is impractical or impossible. See drilling; trepanning.

Grinding of a workpiece at the end of a grind cycle without engaging any further down feed. The grinding forces are allowed to subside with time, ensuring a precision surface.

It is also called the unit power, or power constant, which is equal to the power required to cut a material at the rate of one cubic inch per minute or one cubic centimeter per minute. The units of measure are: hp/in.3/min. (customary U.S. system) and kW/cm3/min. (metric system).

Bushing or toolholder that permits affixing a variety of taper- and straight-shank tools to a machine spindle.

Mass finishing process in which workpieces are individually mounted on spindles then lowered into a rotating tub containing the finishing media. In most applications, the spindles rotate at 10 rpm to 3,000 rpm, but, in some cases, the spindles oscillate up and down instead of rotating.

Milling while simultaneously rotating and feeding the workpiece to create a spiral form. Often used to mill flutes on endmill and twist-drill blanks.

Form of metal characterized by a porous condition that is the result of the decomposition or reduction of a compound without fusion. The term is applied to forms of iron, titanium, zirconium, uranium, plutonium and the platinum group metals.

Tool, guided by a pilot, used to machine a recess around a hole.

Similar to counterboring except that, in spotfacing, material around the original hole is cut. Application example: the recessed area into which a washer fits. See counterboring; countersinking.