| A-axis |
A rotational axis that describes motion around the X-axis. |
| accuracy |
The exactness of a measurement compared to the desired result. |
| automatic magazine bar feeder |
A chamber that allows the feeding of bar stock, one at a time, into a machine. |
| axes |
An imaginary line used to measure the distances of objects in the Cartesian coordinate system. |
| axial approach |
A tool approach that runs parallel to the axis of a cylindrical workpiece. Also called the parallel orientation. |
| backworking tool station |
A toolholding station that is located opposite the sub spindle and is used to machine the back end of parts. |
| bar stock |
Raw material purchased from metal manufacturers in the form of long bars. Bar stock may be round, square, or hexagonal. |
| B-axis |
A rotational axis that describes motion around the Y-axis. |
| blueprint |
A document containing all the instructions necessary to manufacture a part. The key sections of a blueprint are the drawing, dimensions, and notes. |
| boring |
The process of using a single-point tool to enlarge a preexisting hole. |
| cam |
A circular or cylindrical machine component that converts rotational movement into linear movement. A cam controls the feed rate and depth of cut of cutting tools on the automatic bar machine. |
| Cartesian coordinate system |
The system that describes the location of an object by numerically expressing its distance from a fixed position along three imaginary linear axes. |
| C-axis |
A rotational axis that describes motion around the Z-axis. |
| chatter |
The occasional vibration between a workpiece and a cutting tool. Chatter decreases machining productivity, negatively impacts surface quality, and increases tool wear. |
| chuck |
A device that holds a workpiece in place as it rotates. The chuck commonly has three or four jaws that can be adjusted to fit various sizes of parts. |
| CNC Swiss-type lathe |
A sophisticated CNC machine with a sliding headstock and fixed bushing that enables the creation of small, complex, cylindrical parts in one cycle. |
| CNC turning center |
A sophisticated CNC lathe that specializes in turning, boring, drilling, and threading operations, all at the same location. |
| collet |
A slitted device that holds a workpiece in place as it rotates. A collet has a hole through which the workpiece passes, and it is designed to hold specific dimensions. Collets can also be used to hold cutting tools. |
| computer numerical control |
The use of a computer and special programs to carry out various machining operations. The turning center and CNC Swiss-type lathe are examples of lathes equipped with computer numerical control. |
| contour turning |
An operation performed on a lathe that feeds a tool along a curved line in order to create curved, cylindrical shapes. |
| conveyor |
The belt that carries finished parts to a parts bucket. |
| cutoff |
An operation performed on the lathe that uses a cutting tool to separate a part from the rest of the stock. |
| cutting tool |
A device with sharp edges used to cut metal. Cutting tools are either single-point or multi-point tools. |
| cycle |
The time during which a machine works on a single part. |
| deflection |
The vibration or shift in position of a workpiece due to a lack of support. Deflection often causes incorrect measurements. |
| depth of cut |
The amount of material that is removed with one pass of a cutting tool. |
| dimension |
The desired measurement of a feature on a part. |
| drilling |
The process of using a multi-point tool to penetrate the surface of a workpiece and make a round hole. |
| dry run |
A trial run of the part program without any parts or cutting fluid. |
| engine lathe |
The original and most basic type of lathe. |
| facing |
An operation performed on a lathe that feeds a single-point tool into the end of a cylindrical workpiece to create a flat surface. |
| feed |
The linear movement of a cutting tool into a part to remove material. |
| fixed automation |
A process using mechanized machinery to perform fixed and repetitive operations in order to produce a high volume of similar parts. |
| fixed bushing |
A hollow, cylindrical guide for bar stock on Swiss-type lathes that enables the creation of very small parts with excellent tolerances. |
| gang tool post |
A component that holds several cutting tools in a row. On the CNC Swiss-type lathe, the gang tool post is located above the bushing and approaches the workpiece from the radial orientation. |
| ID grooving |
The process of cutting an internal channel or passageway into a drilled hole. |
| indexing |
The changing of machine components to a different fixed position. |
| inner-diameter operation |
Cutting operations that take place on the interior surface of a workpiece on a lathe. |
| lathe |
A machine tool commonly used to create cylindrical forms. A lathe holds a cylindrical workpiece on one or both ends. The cutting tool is gradually passed along the surface of the rotating part. |
| length-to-diameter ratio |
The measurement relationship between the length and diameter of a part. If a part has a 4:1 length-to-diameter ratio, then the part's length is 4 times the measurement of the diameter. |
| linear axes |
The axes that describe movement along a straight line. |
| live tool |
A cutting tool mounted in its own powered spindle on a CNC lathe. Live tooling allows tools to cut off center, perform milling operations, or create holes on the part's outer diameter while the part is held in the spindle. |
| machine control unit |
A small, powerful computer that controls and operates a CNC machine. |
| milling |
A machining operation that uses a multi-point horizontal or vertical cutter to remove metal from the surface of a workpiece. |
| multi-point cutting tool |
A machining tool that has two or more cutting edges. |
| OD chamfering |
An operation performed on a lathe that feeds a tool to create an angled edge on the workpiece. |
| OD threading |
An operation performed on a lathe that creates a long, spiraling ridge down the outer surface of a workpiece. |
| off center |
Any location on a part that deviates from the part's centerline. |
| on center |
The location on a part that is aligned with the part's centerline. |
| operator |
The person responsible for running the CNC machine on the shop floor. |
| opposite tool post |
A toolholding station that is located opposite the fixed bushing on a CNC Swiss-type lathe. |
| outer-diameter operation |
Cutting operations that take place on the outer surface of a workpiece on a lathe. |
| part program |
A series of numerical instructions used by a CNC machine to perform the necessary sequence of operations to machine a specific workpiece. |
| part programmer |
The person responsible for the creation of a part program. The part programmer translates the workpiece design into program instructions for the CNC machine. |
| precision |
The degree to which an instrument will repeat the same measurement over a period of time. |
| primary operation |
One of the main machining operations that contributes to the completion of a part. |
| radial approach |
A tool approach that runs perpendicular to the axis of a cylindrical workpiece. Also called the perpendicular orientation. |
| reaming |
The process of using a multi-point tool to smooth the interior surface of a hole. |
| rigidity |
The quality of a workpiece characterized by being stiff and inflexible. A setup with good rigidity reduces vibration or wobble. |
| rotational axes |
An axis that describes turning or rotational movement around a linear axis. |
| screw machine |
An automated turning machine that continuously creates a number of finished parts from bar stock. Bar stock advances through the spindle and is held by a collet. It is also commonly called a bar machine. |
| secondary operation |
An additional operation required to finish a part that is performed on a separate machine from the machine that made the primary cuts. |
| sliding headstock |
The end of a Swiss-type lathe that contains the spindle and the drive that rotates the workpiece. The headstock also provides feed for the workpiece as well. |
| slotting |
A milling operation that cuts a long groove in the surface of a workpiece. |
| speed |
The rate of rotational movement of a workpiece. Speeds are measured in revolutions per minute or surface feet per minute. |
| spindle |
The component of a machine that spins. On a lathe, the spindle is located in the headstock and houses the workholder. |
| sub spindle |
The source of workpiece rotation that is found opposite the main spindle and fixed bushing. The sub spindle is also called the pick off or back spindle. |
| Swiss-type screw machine |
A modified automated turret lathe distinguished by a sliding headstock and fixed bushing. Swiss-type machines are capable of creating very small parts with excellent tolerances. |
| tailstock |
The component located at the end of a lathe opposite the headstock that supports the end of longer workpieces. |
| taper turning |
An operation performed on a lathe that feeds a tool at an angle to the length of the workpiece in order to create a conical shape. |
| tapping |
The process of cutting internal threads in a workpiece with a multi-point tool. |
| tolerance |
An unwanted but acceptable deviation from a given dimension. Tolerances indicate the allowable difference between a physical feature and its intended design. |
| turret |
The component of a lathe that holds a number of cutting tools. The turret rotates to place tools in the cutting position. |
| turret lathe |
A lathe with a mounted device that holds multiple cutting tools. The turret rotates to position one specific cutting tool in place after another. |
| workholder |
A device used to position and hold a workpiece in place. |
| workpiece |
A part that is being worked on. It may be subject to grinding, cutting, welding, forming, or other operations. |
| X-axis |
The linear axis on a lathe perpendicular to the Z-axis that indicates distances from the part's centerline. |
| Y-axis |
The linear axis that is always perpendicular to both the X- and Z-axis. Unlike most lathes, CNC Swiss-type lathes may have component motions along a Y-axis. |
| Z-axis |
The linear axis that is always parallel to a lathe's main spindle. |