Overview of Machine Tools 121

abrasive grains

A small, hard particle embedded in a cutting or grinding surface to remove material. Abrasive grains can cut or shape hard metals efficiently.

accuracy

The degree to which a machined dimension matches its intended value. Accuracy determines whether a part meets its required measurements.

additive manufacturing

AM. A process that builds parts by adding material layer by layer rather than removing it. Additive manufacturing supports rapid prototyping and produces complex shapes that machining alone cannot achieve.

automation

The use of systems the can perform tasks with minimal human intervention. Automation improves consistency and efficiency in manufacturing environments.

band saws

A saw that uses a continuous loop of metal teeth to cut material. Band saws often cut straight lines or gentle curves in bars, tubes, or plates.

bar feeders

An automated device attached to a lathe that feeds long bars of raw material into the spindle during machining. A bar feeder allows continuous production by supplying material consistently and reducing manual loading time.

bar stock

Raw material supplied in long, cylindrical, or rectangular sections. Bar stock is commonly used as workpieces for turning, cutting, or milling operations.

bed

The main supporting structure of a lathe that connects the headstock and tailstock. The bed provides a rigid, stable foundation for precise machining.

bed-type mills

A milling machine with a large, rigid bed that supports the worktable. Bed-type mills are ideal for machining large, flat parts with minimal table movement.

boring

The process of enlarging or finishing an existing hole with a single-point cutting tool. Boring achieves accurate diameters and precise internal surfaces.

brittle

A material property describing the tendency to fracture with little or no plastic deformation when stressed. Brittle materials are hard and wear-resistant but require rigid, low-vibration conditions to avoid sudden failure.

broach

A multi-point cutting tool with teeth that increase in size and fineness along its length. A broach shapes and finishes surfaces quickly and consistently in one pass.

broaching

A cutting process in which a multi-point tool removes material in a single continuous stroke. Broaching performs roughing and finishing in one cut.

broaching machines

A powered device that pushes or pulls a toothed broach across or through a workpiece to remove material. Broaching machines create accurate internal or external shapes in a single stroke.

carbide

A very hard tool material made by bonding tungsten carbide particles with a metal binder. Carbide offers excellent heat resistance and allows tools to cut at high speeds.

carriage

The part of a lathe that carries the cross slide and tool turret or cutting tool along the ways. The carriage provides controlled linear motion.

center

A pointed device that supports a workpiece at one or both ends during rotation. The center ensures accurate alignment and prevent bending or wobbling.

chips

A small piece of material separated from a solid surface during machining. Chips form as a tool shears material away.

chuck

A round device with multiple jaws that holds a workpiece or cutting tool securely during machining. A chuck provides stable workholding on lathes and can hold cutting tools on drill presses, mills, and other machine tools.

circular saws

A saw that uses a rotating disk with teeth or abrasive edges to remove material. Circular saws provide fast cutting for large cross-sections and thick stock.

CNC

Computer numerical control. The use of programmed computer instructions to control machine motion and operations. CNC improves accuracy, repeatability, and enables complex shapes in metal cutting.

collet

A split cylindrical device that clamps around a workpiece or tool. A collet provides precise, uniform workholding for small or delicate parts on lathes, and toolholding for cylindrical cutting tools on mills and other machine tools.

column

The vertical backbone of a mill that supports the spindle and other components. The column holds the spindle or cutting tool over the workpiece and often moves the tool along the workpiece.

column-and-knee mills

A manual milling machine with a spindle mounted in a vertical column and a worktable supported by an adjustable knee. Column-and-knee mills are the most common, basic type of manual mill.

computer numerical control

CNC. The use of programmed computer instructions to control machine motion and operations. Computer numerical control improves accuracy, repeatability, and enables complex shapes in metal cutting.

contours

A curved, non-linear shape on a workpiece. Contours are complex surfaces and features that generally require advanced CNC machines.

counterbores

A cutting tool used to create a flat-bottomed recess at the entrance of a hole. Counterbores are used to accommodate bolt or screw heads, so they fit flush with the workpiece surface.

countersinks

A cutting tool used to create a conical recess at the entrance of a hole. Countersinks allow screw or other fastener heads to sit flush with or below the surface of a workpiece.

cross slide

A movable component of a lathe that supports the cutting tool and moves it perpendicular to the spindle axis. The cross slide controls tool depth and is used to machine outer diameters, face parts, and perform precision cuts.

cutting

The process of using a tool to remove material from a workpiece. Cutting refers to material removal operations in which a cutting edge shears material to form chips.

cutting tool

A device with one or more edges designed to remove material from a solid surface. Cutting tools create the shape, size, and finish required on a workpiece.

data

Information collected from machines, processes, or products that can be analyzed to support decision-making. Data in manufacturing includes measurements from sensors, production logs, and quality records used to optimize performance.

downtime

A period when a machine or production system is not operating due to maintenance, setup, or malfunction. Downtime reduces productivity and can increase costs in manufacturing operations.

drill bits

A multi-point cutting tool used to create round holes in a workpiece. Drill bits can be made of high-speed steel or carbide and are mounted in chucks for drilling operations.

drill presses

A machine tool that uses a rotating drill bit to create or refine round holes. Drill presses provide stable alignment and controlled feed for accurate holemaking.

drilling

A machining operation that creates a round hole by advancing a rotating cutting tool into a workpiece. Drilling uses a drill bit to remove material and produce an initial hole.

end mills

A tall, thin cutting tool with spiral cutting edges on its sides and bottom. End mills are used to cut shoulders, slots, pockets, and complex shapes.

engine lathe

A manually operated lathe used for general-purpose turning, facing, drilling, and threading operations. Engine lathes are the most common type of manual lathe and are controlled directly by an operator.

external gears

A gear with teeth cut on the outer surface of a cylinder or cone. An external gear can be created using pot broaching, where multiple broaches in a cylindrical toolholder cut all teeth simultaneously.

face mills

A cutting tool designed to remove material from large, flat surfaces. Face mills create smooth finishes and efficiently machine broad areas.

facing

A machining operation that cuts a flat surface at the end of a cylindrical workpiece. Facing produces square ends and smooth surfaces for assembly or finishing.

feed handle

A lever used to move a spindle, workpiece, or cutting tool. The feed handle on a drill press move the spindle and cutting tool down towards the workpiece.

finishing

A machining process that produces a smooth, precise surface and final dimensions on a workpiece. Finishing is the final stage of broaching, performed by fine teeth on a broach to achieve tight tolerances.

finishing teeth

The largest, finest teeth on a broach that complete the cut. Finishing teeth provide a smooth surface and precise dimensions.

finishing tools

A cutting tool designed to produce smooth surfaces and precise dimensions. Finishing tools follow roughing operations to achieve the final tolerances and appearance.

form mills

A custom-shaped cutter that matches a specific profile or contour. Form mills machine complex shapes and part features.

friction sawing

Cutting with a saw blade that generates heat to soften the material in front of the blade. Friction sawing is effective for cutting thick or hard metals quickly.

hacksaws

A saw with a straight blade that moves back and forth in a reciprocating motion. Hacksaws are used for small cuts, tight spaces, and low-volume production.

hardness

The ability of a material to resist indentation, wear, or deformation. Hardness helps cutting tools maintain sharp edges under high temperatures and heavy loads.

head

The top portion of a vertical manual mill that holds the spindle and motor. The head positions the cutting tool over the workpiece for precise material removal.

headstock

The end of a lathe that holds the spindle. A headstock provides power and rotational motion to the workpiece.

heat resistance

The ability of a material to retain its hardness and strength at elevated temperatures. Heat resistance refers to a cutting tool’s capacity to maintain performance when exposed to the heat generated during machining.

holemaking

A group of manufacturing operations used to create or enlarge holes in a workpiece. Holemaking includes processes like drilling, boring, and reaming performed on machine tools.

horizontal axis

An imaginary straight line parallel to the ground around which a workpiece or tool rotates. Horizontal axes are common for lathe and turning center spindles.

horizontal mill

A milling machine with a spindle parallel to the ground. Horizontal mills are suited for heavy material removal and machining wide or long surfaces.

hybrid manufacturing

A manufacturing approach that combines additive manufacturing and CNC machining in a single workflow. Hybrid manufacturing leverages the advantages of both methods to produce complex parts with high precision and efficiency.

ID

Internal diameter. The inside surface of a round or cylindrical part feature, such as a hole or bore. ID work refers to machining or finishing operations performed on the internal surface of a cylindrical opening.

index

The process of repositioning a cutting tool or insert to use a fresh cutting edge. To index means to rotate or flip an indexable insert, so a new edge engages the workpiece, extending tool life.

indexable insert

A replaceable piece of cutting material that clamps into a toolholder and provides multiple cutting edges. An indexable insert can be rotated or flipped to expose a new edge, reducing tool costs and downtime.

inner diameter

ID. The inside surface of a round or cylindrical part feature, such as a hole or bore. Inner diameter work refers to machining or finishing operations performed on the internal surface of a cylindrical opening.

internal broaching

A broaching operation in which the tool passes through a hole in the workpiece. Internal broaching creates keyways, splines, internal gear teeth, or other shapes.

internal gears

A gear with teeth cut on the inside surface of a cylindrical or conical bore. An internal gear is typically produced by internal broaching, allowing it to mate with an external gear in a compact assembly.

keyways

A rectangular slot machined along the length of a hole. A keyway allows a key to fit and transfer torque between a shaft and a rotating component.

knee

The adjustable support on a manual milling machine that holds the worktable. The knee allows vertical movement of the table for precise cutting depth.

lathes

A machine tool that rotates a workpiece while a cutting tool shapes its surface. Lathes perform operations like turning, facing, boring, and threading.

machine tool

A powered device that holds a cutting tool and moves it or the workpiece to create a part. Machine tools provide the motion and stability needed for metal cutting.

machining

A manufacturing process that removes material from a workpiece using cutting tools to achieve a desired shape, size, or surface finish. Machining includes operations such as turning, milling, drilling, and grinding performed on machine tools.

manual machines

A machine tool that a person operates directly using handwheels, levers, or switches. Manual machines are less precise and stable than CNC machines.

metal powders

A finely ground metallic material used to create parts in certain additive manufacturing processes. Metal powder melts or fuses to form dense, functional parts.

mills

A machine tool that rotates a multi-point cutter to remove material from a stationary or guided workpiece. Mills produce flat surfaces, pockets, slots, and complex contours.

monitoring systems

Equipment and software that work together to collect and analyze data from machines during operation. Monitoring systems identify problems early and support consistent quality.

multi-axis CNC machines

A CNC machine that uses four or more linear and rotational axes. Multi-axis CNC machines, or multitasking machines, combine the functions of a mill and lathe.

multiple-spindle drills

A drilling machine with two or more spindles that operate simultaneously. Multiple-spindle drills increase production efficiency by performing several holes at once.

multi-point tools

A cutting device with two or more cutting edges. Multi-point tools perform operations like milling or drilling where multiple edges share the cutting load.

OD

Outer diameter. The outside surface of a round or cylindrical workpiece. OD work refers to machining or finishing operations performed on the exterior surface of a cylindrical part.

outer diameter

OD. The outside surface of a round or cylindrical workpiece. Outer diameter work refers to machining or finishing operations performed on the exterior surface of a cylindrical part.

planer-type mills

A very large milling machine with a flat, stationary base and multiple milling heads. Planer-type mills are designed to efficiently machine very large workpieces.

plate stock

Flat, rectangular raw material supplied in large sheets. Plate stock is commonly used for milling, sawing, or forming flat components.

pockets

An interior recess or cavity cut into the surface of a workpiece. Pockets are generally round or square and wider than they are deep.

polymers

A long-chain molecule made of repeating structural units. Polymers form the base material for many plastics and serve as a raw material in some additive manufacturing processes.

pot broaching

A broaching process that uses a cylindrical toolholder filled with multiple broaches to cut external features. Pot broaching is commonly used to produce external gears efficiently and with uniform accuracy.

predictive maintenance

PdM. A maintenance strategy that uses data and analytics to forecast equipment issues before they occur. Predictive maintenance aims to prevent unexpected failures and reduce unplanned downtime.

prototypes

An early version of a part created to test design, function, or manufacturability. Prototypes allow designers and technicians to verify performance before full production.

radial drills

A drill with a movable arm that positions the spindle over large or awkward workpieces. Radial drills support flexible holemaking for parts that cannot easily be moved.

rapid prototyping

A process that quickly creates a physical model of a part or product directly from a digital design. Rapid prototyping often uses additive manufacturing to produce prototypes efficiently for testing and evaluation.

reamers

A cutting tool used to enlarge or finish an existing hole to a precise diameter with a smooth surface. Reamers are commonly used after drilling to improve accuracy and surface finish in holemaking operations.

reciprocates

To move a tool or component back and forth in a straight line. In machining, a blade or cutting tool that reciprocates alternates its motion forward and backward to perform cutting or shaping operations.

repeatability

The ability of a machine to produce the same motion or result consistently over multiple cycles. Repeatability ensures that identical parts match one another during production.

robotics

A programmable mechanical system that performs tasks like loading, unloading, or material handling. Robotics increase speed and safety in manufacturing facilities.

roughing

A machining process that removes large amounts of material quickly, leaving a rough surface. Roughing is the first stage of broaching, performed by coarse teeth on a broach to rapidly shape the workpiece.

roughing teeth

The smallest, coarsest teeth on a broach that make the initial cuts in a workpiece. Roughing teeth remove large amounts of material to prepare the surface for subsequent cuts.

roughing tools

A cutting tool designed to remove large amounts of material quickly. Roughing tools prioritize speed over surface finish and are used in the initial machining stages.

runs

A continuous period of production in which a set of parts is manufactured without interruption. A run refers to the quantity of parts produced under the same setup, tooling, and machine conditions.

saws

A cutting device that uses a toothed or abrasive blade to separate material. Saws divide stock into workable sizes or shapes.

semi-finishing teeth

The teeth on a broach that follow the roughing teeth and precede the finishing teeth. Semi-finishing teeth remove moderate amounts of material to refine the workpiece shape.

sensors

A device that detects physical conditions such as temperature, vibration, or position. Sensors detect and transmit data on machines and processes.

setup

The process of preparing a workpiece, tools, and machine parameters to prepare for a manufacturing operation. Setup ensures the machine is ready to accurately and efficiently produce parts according to specifications.

shell mills

A large milling cutter mounted on an arbor for heavy material removal. Shell mills efficiently machine wide surfaces while maintaining accuracy.

single-point cutting tools

A device with only one cutting edge. Single-point cutting tools perform operations where a single edge shapes the workpiece.

slab broach

A flat broach designed to cut external workpiece surfaces. A slab broach performs surface broaching operations.

smart manufacturing

A production approach that digitally connects machines, tools, and processes to optimize operations. Smart manufacturing uses sensors, monitoring systems, and data analytics to improve accuracy, efficiency, and decision-making.

spindle

The rotating component of a machine that holds either a cutting tool or a workpiece. A spindle provides motion and power for metal cutting operations.

splines

A series of evenly spaced ridges or teeth on a shaft or inside a hole. Splines transmit torque while maintaining alignment between components.

surface broaching

A broaching operation that removes material from the exterior of a workpiece. Surface broaching is commonly used to create flat or contoured surfaces.

tailstock

The end of a lathe opposite the spindle that can supports the workpiece with a center or hold a tool. A tailstock can provide stability and reduce deflection for long workpieces.

tapers

A gradual change in diameter along the length of a cylindrical or conical surface. Taper describes a feature where the diameter increases or decreases uniformly from one end to the other.

tapping

The process of cutting internal threads into a hole. Tapping prepares a hole to accept screws or bolts.

throughput

The amount of work or number of parts a machine or production system can complete in a given period of time. Throughput measures productivity and efficiency in a manufacturing environment.

tolerances

The allowable deviation from a desired dimension. Tolerance ensures parts fit together and function correctly even with minor variations.

tool geometry

The shape and angles of a cutting tool’s surfaces and edges. Tool geometry influences chip formation, cutting forces, surface finish, and tool life.

tool life

The duration a cutting tool remains effective before it must be replaced or re-sharpened. Tool life affects productivity, cost, and surface quality of machined parts.

toolholder

A device that secures a cutting tool in place on a machine. A toolholder ensures rigidity and accurate positioning during machining operations.

tooling

The collective set of tools, fixtures, holders, and related equipment used to manufacture or assemble parts. Tooling includes cutting tools, workholding devices, and accessories required to perform specific production operations.

T-slot cutters

A cutter designed to machine T-shaped channels in a workpiece. T-slot cutters create slots for securing parts, fixtures, or fasteners.

tube stock

Hollow raw material supplied in long sections. Tube stock is used when parts require lightweight structures, passages, or hollow shafts.

turning

A machining operation in which a single-point cutting tool removes material along the outer surface of a rotating workpiece. Turning reduces diameters and creates smooth finishes on cylindrical parts.

turret

A rotating component on a lathe that holds multiple cutting tools. Turrets increase efficiency by allowing quick indexing to different tools.

turret lathes

A manual lathe with a multi-sided turret that holds several cutting tools. Turret lathes allow rapid tool changes and multiple operations in a single setup.

vertical axis

An imaginary straight line perpendicular to the ground around which a workpiece or tool rotates. Vertical axesare common for mill and machining center spindles.

vertical mill

A milling machine with a spindle perpendicular to the ground. Vertical mills are more common and can generally create more intricate parts than horizontal mills.

waste

Any material, time, or effort that does not add value to a finished part. Waste reduction improves efficiency and lowers production cost.

ways

Two precisely measured, parallel tracks on a machine tool. Ways guide the movement of components like a lathe carriage or mill column.

wear resistance

The ability of a material to withstand gradual loss of material due to friction, abrasion, or cutting forces. Wear resistance describes how well a cutting tool or insert maintains its shape and sharpness during machining.

workholding

The method or devices used to secure a workpiece during machining. Workholding ensures stability, accuracy, and safety during cutting operations.

workholding device

Any equipment used to locate, support, and secure a workpiece during a manufacturing operation. Workholding devices include chucks, vises, fixtures, and clamps that maintain part position and stability.

workpiece

A raw material or in-process component that undergoes one or more manufacturing operations. A workpiece is any material shaped or modified to produce a finished part.

worktable

The flat surface that supports the workpiece and workholding devices on a mill. The worktable has slots used to secure workholding devices and often moves or adjusts to position the workpiece.