Precision Machining Glossary

CNC Swiss Machining Terminology


5S Methodology: A systematic form of visual management that maximizes efficiency and minimizes waste. Originating in Japan, 5S stands for: Sort, Set in Order, Shine, Standardize, and Sustain.


Acid Bath: A type of passivation that immerses parts in citric or nitric acid to increase performance and durability of the parts.
Alloy: Metal formed by mixing 2 or more different metals. To learn more about alloy steel, and the different types of steel used to turn precision components, see our blog post “Classes of Steel Commonly Used in Precision Machining.”
Annealing: The controlled heating and cooling of metal to remove stresses and make it easier to work with (machine).
Anodizing: To coat a metal with a protective oxide layer. The finish can be decorative, durable, and corrosion resistant, and provides a better surface for paint and adhesion. Aluminum is the most common metal used for anodizing, but titanium and magnesium can also be treated this way. The process is actually an electrolytic passivation process used to increase the thickness of the natural oxide layer on the surface of the metal. Anodizing is available in a number of colors. More about anodizing CNC Swiss precision machined parts can be found in our blog post “Anodizing Precision Machined Components.”
AS9100: An aerospace standard based on the ISO 9001 quality system requirements. AS9100 takes the ISO 9001 requirements and supplements them with additional quality system requirements, which are established by the aerospace industry in order to satisfy DOD (Department of Defense), NASA (National Aeronautics and Space Administration) and FAA (Federal Aviation Administration) quality requirements. Pioneer Service is certified for AS9100; see our certification here. To learn more about the differences between AS9100D and ISO 9001, see our blog post “AS9100D vs ISO 9001 – What the Difference and Why Do We Have Both.”
ASME (American Society of Mechanical Engineers): Develops and publishes voluntary consensus technical standards for a wide range of materials, products, systems, and services.
ASTM (American Society for Testing and Materials): Is an international standards organization that develops and publishes voluntary consensus technical standards for a wide range of materials, products, systems, and services.  ASTM Standards are widely used in the manufacturing industry in general.


Bar Feeder: An automated machine that is typically paired with a Swiss screw machine. The bar feeder delivers material to the lathe tool in the machine as needed, which in turn minimizes operator supervision.
Bar Stock: Metal bars of various lengths. It can be purchased in a variety of shapes (hexagon, flat, octagon, round and square), but for CNC Swiss machining and turning, round bar stock is almost always specified.
Barrel Plating: Used for small, light weight machined components. Parts are put in a barrel with the plating solution and then rotated around (tumbled) while the electric current plates the parts with the required material.
Black Oxide: A conversion coating that is produced through a chemical reaction when component parts are dipped in an alkaline salt solution. Learn more about black oxide. To learn more about other types of surface finishing that adds to or alters the component surface of precision machined components, see our blog post ” Finishing Services that Add To or Alter the Component Surface.”
Bolt: A bar that slides into a socket to fasten one piece to another. Blots requiring tight tolerances, and fine surface finishes, are commonly made with precision machining on CNS Swiss and CNC Turning machines.
Bore: A hole milled through material.
Boring: Process that is used to enlarge a hole with the use of single point tool.
Brass: Nonferrous metal consisting mostly of copper and zinc.
Broach: A toothed cutting tool that is used to remove metal or plastic. In Swiss CNC machining a broach is used to cut an asymmetric shape in the metal or plastic. It is commonly used for odd shapes like non-circular holes, keyways, flat surfaces or splines.
Burnishing: The process of finishing a metal through contact with another harder metal. Can make it smooth or glossy as if polished. To learn more about other types of surface finishing for precision machined components, see our blog post “Finishing Services that Add To or Alter the Component Surface.”
Burr: A rough edge or ridge left on a metal or plastic part that has been machined.


Caliper: A device to measure inside and outside dimensions on a component.
Carburizing: A heat treatment process that adds carbon to steel or iron components to harden the surface.
Case Hardening: The process of adding carbon to the outer surface of steel by heat treating it. This makes the surface of the steel (the case) substantially harder than the core. The process is often used to improve wear resistance. To learn more about case hardening, and the other types of finishing treatments for precision turned components, see our blog post “Finishing Services that Add To or Alter the Component Surface.”
Centerless Grinding: Used for long thin parts, the component rests on a knife edge support, and is ground down while rotated by feeder wheel. To learn more about Centerless Grinding capabilities at Pioneer Service, visit our Centerless Grinding Capabilities page. To learn more about centerless grinding in general, visit our blog post “Centerless Grinding of Precision Machined Components“.
Chamfer: A beveled or angular surface cut on the edge or corner of a machined part.
Chatter: A harmonic vibration or natural resonance that derives from the machine tool under certain conditions. Chatter can interfere with proper cutting, can produce cutting errors, and/or a bad surface finish.
Chip: In a machine shop, chips are the small pieces of excess material that are removed from the component (plastic or metal) that is being machined.
Chrome Plating: The process of depositing a thin layer of chromium onto a metal component. Chrome plating can be decorative, provide corrosion resistance, ease cleaning procedures, or increase surface hardness depending on the environment and use of the final product.
Chuck: A type of clamp that holds round components. Used in CNC Swiss machining a chuck holds the round bar stock as it is fed through the machine. Capable of OD and ID clamping.
CMM (Coordinate Measuring Machine): CNC controlled machine used for measuring shapes and dimensions on components, commonly used in precision CNC Swiss machine shops.
CNC (Computer Numerically Controlled): Using the aid of a computer to control and monitor the movements of a machine that was previously run by hand. The machine can several axes of movements, in either a linear or rotary axis.
CNC Machining: Computer run machining process that removes metal or plastic from bar stock to create a desired shape. It can be used to create a variety of complex shapes with tight tolerances. To learn about the 5 most common types of CNC Machining, see our blog post, “The 5 Most Common Types of Preicision CNC Machining“.
CNC Milling: Milling machine that is run by a computer program. Milling machines use rotary cutters to remove material. Learn more about the difference between milling and turning on our blog post, “Turning vs Milling: What’s the Difference for precision machining?”
CNC Turning: Similar to a lathe, a computer-controlled machining center that removes metal or plastic from round bar stock. Typically, does turning, boring, drilling and threading. Learn more about CNC Turning.
Cobot: A computer-controlled robotic device designed to assist a person. Also know as a collaborative robot.
Cold Rolled Steel: Refers to hot rolled steel material that has gone through an additional finishing process. The additional steps are done after the hot rolled steel has cooled, and can include drawing, turning, grinding and polishing to produce a superior surface finish (as well as tighter tolerances,superior concentricity and superior straightness) when compared to hot rolled steel.Most steel bar stock for precision machining uses cold rolled steel. Cold rolled steel is also known as cold form steel, and cold drawn steel.
Collet: A type of chuck that creates a tight collar around a round object to hold it firmly in place. Using in precision machining, a collet is used to hold the round bar stock in place while the components are turned or milled.
Computer Aided Design (CAD): Computer software to aid engineers in the drafting, modification, and optimization of a part.
Concentric: Accurately centered or having a common center.
Continuous Improvement Plan (CIP): The ongoing effort to improve products, services and processes over time to gain efficiencies and improve quality, safety, flexibility and delivery. There is an emphasis on small incremental changes at all levels of the organization that make positive impacts.
Corrosion: Oxidation (rusting) of a metal part
Cutting Oil: A type of coolant and lubricant used to keep the machine at a stable temperature, maximize the life of the machine, and prevent rust on machine parts.
Cycle Time: The total time it takes to produce one part on a machine.


Deburring: The process of removing small ragged edges/pieces of material creating during the machining process (burrs). Deburring can be done by hand, with compressed air, and in a machine depending on the shape, weight and type of material.
Depth Gage: Device used to measure hole or recess depth.
Depth of Cut (DOC): A measurement of how much material is being removed along one axis.
Diameter: The measurement through the center of a circle or sphere.
Die: A metal block used to form materials such as sheet metal and plastic.
Dowel Pin: A smaller piece of a dowel rod. Used to align parts that need to be assembled.


Eccentric: A circle that does not have a geometric center. Also called off-center.
EDM: Electrical Discharge Machine: Can be used to create additional holes in a machined component using electrical discharges (sparks). To learn more about EDM and the other most common types of precision CNC machining processes, see our blog post “The 5 Most Common Types of Precision CNC Machining.”
Electroless Nickel Plating: A layer of nickel-phosphorus or nickel-boron alloy is deposited on the surface of a machined component (metal or plastic). This reduces corrosion or wear to the component. To learn more about Electroless Plating for precision machined components, as well as other surface finishing treatment, see our blog post “Finishing Services that Add To or Alter the Component Surface.”
ERP (Enterprise Resource Planning): Is software used to manage a company’s business processes for optimum efficiencies.


Feed Rate: The rate at which the cutting tools and the machined component move in relation to each other.
Feed: The act of moving the material relative to the machine cutter. In precision CNC Swiss machine shopes, feeding is usually accomplished using automotice bar loading equipment to achieve high effeciencies.
Ferrous: Metal alloy that has iron as its major ingredient.
First Article Inspection (FAI): A formal reporting process that provides documentation that all measurements from a component design have been verified after production. To learn more about the FAI (First Article Inspection) process and reports, please see our blog post, “FAI (First Article Inspection) Reports for Precision Machining.”


G-Code: The coding program a CNC swiss operator used to tell the machine what movements to make, speeds at which to move, and many other functions for precision machining components.
Gauge: A device for measuring or checking dimensions on a component.
Grinding: Removing material with a powered wheel. To learn more about the different types of finishing processes that remove or reshape a precision machined component surface, see our blog post ” Finishing Services that Remove or Reshape the Component Surface.”


Hardening: Heat treating steel which increases the hardness and tensile strength.
Hardness: The resistance of a material measured by one of the following hardness tests: Brinell, Knoop, Mohs, Rockwell, or Vickers. Directly related to tensile strength.
Heat Treating: Is a metal working process to change the characteristics of the metal. There are several types of heat treatment techniques include annealing, case hardening, precipitation strengthening, tempering, carburizing, normalizing and quenching. To learn more about heat treating of CNC Swiss components, see our blog post “Heat Treatment of Precision Turned Parts“.
Honing: The process of finishing a ground surface to a high degree of smoothness and accuracy. Uses abrasive blocks with controlled pressure and rotary or reciprocating motion. To learn more about the difference between honing and lapping, see our blog post, “Honing and Lapping Precision Turned Components.”


IIoT (Industrial Internet of Things): An evolution of devices that are interconnected with computers’ applications. This integration allows for data collection, exchange, and analysis, and potential improvements in overall process. To learn more about the IIoT (Industrial Internet of Things), see our blog post “The Industrial Internet of Things and What it Means to Precision Machining.”
Insert: A component that is used to join two objects together.
ISO 9001:2015 (International Organization of Standards): A standard that sets out the requirements for a quality management system. It is designed to improve quality and effeciency and in return generate improved customer satisfaction. A current version of the standard, ISO 9001:2015 replaced the previous version (ISO 9001:2008). Pioneer Service is certified for ISO 9001:2015; see our certification here. To learn more about the difference between AS9100D and ISO 9001, see our blog post “AS9100D vs ISO9001 – What’s the Difference and Why Do We Have Both?


Just-In-Time Manufacturing (JIT): A methodology which aims to reduce time within the production system, response times from suppliers, and response time to customers to create the most efficient manufacturing operation.


Kanban: Developed by industrial engineer, Taiichi Ohnom, Kanban is a proven effective scheduling system used with the lean manufacturing process and just-in-time manufacturing (JIT).
Knurl: The gripping surface of a component (usually a knob) make by creating uniformly cut diagonal lines in the metal or plastic (sometimes called scoring). The knurls make it easier to grip the knob for turning. To learn more about other types of surface finishing treatments for CNC Swiss and CNC Turned components, see our blog post, “Finishing Services that Add To or Alter the Component Surface.”


Lapping: The process of using a soft metal tool and fine abrasive to create a precision finish on a part. To learn more about honing and lapping of CNC Swiss precision machined parts, see our blog post “Honing and Lapping Precision Turned Components.”
Lathe: A machine for shaping metal or plastic material by rotating bar stock, and using machine cutting tools to create small components. Components made on lathes are also called turned components.  CNC Lathes are one of the five most common types of precision machining. More about lathes and the other types of precision machining, can be found in our blog post, “The 5 Most Common Types of Precision Machining.
Lead In/Lead Out: How a CNC program approaches and/or leaves the part before cutting. Typically, this is programmed through CAM software.


Machine Vision Inspection System: A programmable and automatic highly accurate machine to check the accuarcy of internal and external features on a component. Pioneer Services utilizes the Keyence Vision Measurement System.=
Milling: Using a rotary cutter to remove material, this common type of precision machining is commonly used for square or rectangular components.  To learn more about milling and the other 4 most common types of precision machining, see our blog post, ” The 5 Most Common Types of Precision CNC Machining.” To learn more about the difference between milling and turning, see our blog post, “Turning vs Milling: What’s the Difference for Precision Machining“.


Non-Ferrous: Metal that contains no iron (such as brass or aluminum).


Operator: Or machinist, implements the plans created by a CNC programmer to run a computer-numeric controlled machine. This also included changing out tools as indicated by the program and overseeing cycle time.


Passivation: Treatment to the surface (adding a micro-coating) of a component that reduces the likelihood of corrosion. Components are submerged in an acid bath (citric or nitric) for a set amount time at a set temperature. To learn more about passivating, and other surface treatments for precision turned components, see our blog post “Finishing Services that Add To or Alter the Component Surface.”
Pilot Hole: A small hole drilled as a guide for a larger hole. In machining this is often used when a broach is required. The pilot hole is drilled deeper than the broad which allows room for the excess metal to accumulate while the larger hole is being cut.
Pitch: The axial distance between threads, which will be equal to the lead in a single start screw.
Plating: Plating is the process where a thin layer of metal is deposited onto a surface. It offers corrosion resistance, improves solderability, provides hardening, improves paint adhesion, alters conductivity, offers decorative finishing, improves wearability, reduces friction, and a number of other benefits. Most plating for precision machined components is electroplated. Depending on the size, weight, complexity and shape of the part, the components may be barrel plated, or rack plated. A wide variety of plating is available with nickel, zinc, and chrome plating the most commonly used for machined parts. To learn more about plating, and other types of surface finishing treatments for precision machined components, see our blog post “Finishing Services that Add To or Alter the Component Surface.
Polishing: Making the surface of a material or part smooth and shiny by rubbing it repeatedly.
Porosity: Is the quality of being porous, or full of tiny holes.
Precision Machining: The process of machining tight tolerance, complex shapes from metal and plastic bar stock. Pioneer Service is a leading contract manufacturer of precision machined metal and plastic components in the US.
Print: The blueprints or drawings that define what dimensions the part should be.
Production Part Approval Process (PPAP): A quality documentation process widely used by the automotive and aerospace industries to verify that specified dimensions are within required tolerances after a production process. There are 5 different levels of a PPAP that can be specified, which outline what data is required along with the the Part Submission Warrant (PSW) form. To learn more abou the PPAP (Production Part Approval Process), see our blog post “PPAP (Production Part Approval Process for Precision Turned Parts.”
Profilometer: A piece of testing equipment that measures the roughness of the surface of a component. This type of equipment is commonly found in the quality department of CNC Swiss precision machine shops.


Quenching: A rapid cooling process that is often used in the heat treatment process to bring the temperature of a material down quickly.


Rack Plating: Used for large, heavy, delicate, more complex parts when barrel plating is not appropriate. The parts are affixed to a rack with wires, springs or screws. The racks are then submerged in the plating tanks. There will be marks on the parts from the attachment method to the rack and some consideration should be given to this when the parts are designed.
Resistance: A material’s toughness against fracture when stressed.
Resolution: How accurately a CNC machine or component can discern a position.
Rockwell Scale: A hardness scale based on indentation hardness of a material. This differential-depth method eliminates errors associated with mechanical imperfections in the system.
RoHS (Restriction of Hazardous Substances): A directive adopted by the European Union in 2003 to restrict the use of hazardous substances in the electrical products industry. It is intended to reduce the use of 10 different materials in the production of products, but has been widely called the “lead free directive”.  To learn more about RoHS compliancy and how it affects CNC Swiss shops like Pioneer Service, see our blog post “RoHS Compliancy in a Precision Machine Shop“.


Screw Machine: An automatic lathe that will run production parts with minimal human intervention throughout the production run. Screw machines can be single or mutli-spindle and will run small and medium size parts in medium and high volumes. A screw machine is used to make bolts, shafts, screws, and pins, as well as a wide variety of other types of fasteners and components.
SolidWorks: A commonly used computer-aided design (CAD) program that runs on Microsoft Windows.
Spindle: The rotating axis of the machine, which often has a shaft at its center. Some machines have only one spindle, which others are multispindle machines.
Standoff: A component that prevents two other parts from coming into contact with each other.
Surface Finish: The measure of the overall texture of a surface that is characterized by the lay, surface roughness, and waviness of the surface. To learn more about measuring surface finishes on CNC Swiss precision machined parts, see our blog post “Measuring Surface Finishes on Precision Machined CNC Swiss Turned Components.”
Surface Speed: A measure of how fast the tool is moving over the material as it cuts. Measured in SFM (Surface Feet Per Minute), this can also be called Cutting Speed.
Swiss Screw Machining: (Also known as swiss lathes, or swiss automatic lathe). The holding mechanism (collet) for the bar stock is recessed behind the guide bushing. This offers additional support to the material as it is being machined providing better tolerances for the finishing operations. These are also particularly effective at turning small diameter parts. The name Swiss Screw machine comes from the fact that the first types of these machines were created in Switzerland. Adding CNC to the Swiss screw machines came about in the 1990s. Click here to learn more about Swiss Machining.


Tapping: The process of cutting screw threads inside of a hole.
Tensile Strength: The property of a metal which resists force applied to pull it apart.
Thread Gauge: Device used to measure the threads on a machined component.
Thread Relief: For a turned (machined) part, an undercut is also known as a “thread neck”, “thread relief” or “relief groove”. They are often used at the end of the threaded portion of a shaft or screw to provide clearance for the cutting tool.
Thru-Feed: A type of centerless grinding used only for parts with a single-size diameter. Parts are fed through grinding wheels to remove unwanted material.
Tolerance: The allowable amount that the finished component can differ from the original specified dimensions. Usually expressed at +/- a certain number of thousandths.
Torque: The rotational force (or turning force) a spindle drive motor generates.
Torx: A type of screw head characterized by a 6-point star-shaped pattern. This type of screw head can be made with swiss CNC machining equipment.


Workholding: Any implement that is used to hold a workpiece in place while it’s being machined.

“Wow, that is great news! You guys are heroes.
(You were already but now super heroes!)”

Eric – Electric Vehicle Company


Learn More


Learn More


Learn More


Learn More