McGuire Glossary of Fastener Terminology

C - 289 terms

C - National Coarse thread, or when followed by a number (ex: C-35) hardness measured on the Rockwell C Scale.

C-RING - A retention method used in bit holders that has a ring which locks around corresponding grooves in an insert bit to firmly hold it is place.

CADMIUM - An element that has atomic number 48. It is often used as a plating metal because it possesses superior corrosion resistance (compared to zinc) and high lubricity which lowers the frictional coefficient of the surface. Highly toxic; restricted under the RoHS directive.

CADMIUM ELECTROPLATING - Coating of threaded fasteners with cadmium can provide the parts with excellent corrosion resistance. The appearance of the coating is bright silver or yellow if subsequently passivated. The friction values associated with this coating are also comparatively low. A chromate conversion coasting is frequently applied to the surface to improve corrosion resistance. Cadmium is not frequently used because of the environmental and worker health problems associated with the coating process and should not be used in applications above 250 C or when contact with food is possible.

CADMIUM PLATING (ASTM B766) - An electrolytically deposited, silver-gray plating which provides exceptionally good protection against corrosion, particularly in a salt atmosphere. Chromate Clear Dip is a protective film dip applied after electroplating, and gives additional corrosion protection and a bright, shiny appearance which resists staining. Cadmium is a known carcinogen, and has been banned in many countries. Commercial grades of cadmium plating are typically applied a minimum of 5 microns think (.0002"). Cadmium plating with a chromate dip must not show white corrosion products at 96 hours of salt spray testing per ASTM B117.

CADMIUM, ELECTROPLATED, (WAXED) - Bright silver-gray, dull gray, or black finish. Particularly effective corrosion protection, coloring and paint bonding. Good electrical conductivity quality. Not suggested unless absolutely necessary due to toxic content and extremely high cost.

CAGE CODE - The Commercial and Government Entity (CAGE) is a five-character ID number used extensively within the U.S. Federal government, assigned by the Department of Defense's Defense Logistics Agency (DLA). The CAGE code provides a standardized method of identifying a given facility at a specific location. CAGE code is also a part of a SAM registration.

CALIBRATION - Calibration is the set of operations which establish, under specified conditions, the relationship between values of quantities indicated by a measuring instrument or measuring system, or values represented by a material measure or a reference material and the corresponding values realized by standards.

CALIBRATION CERTIFICATE OR REPORT - The document that presents calibration results and other information relevant to a calibration.

CALIBRATION FREQUENCY - Is the time intervals at which instruments, gages and masters are calibrated. These intervals are determined by their user based on the conditions of their use to ensure their performance or size remain with acceptable limits.

CALIBRATION LIMITS - This is a tolerance applied to gages and instruments beyond which they are not considered suitable for use.

CAM OUT - When a driver bit slips out of the drive recess of a fastener during installation once proper torque has been met. Repeated cam-out can lead to stripping of the drive. Most commonly occurs on Phillips drive fasteners.

CAMA - Concrete Anchor Manufacturer's Association

CAPACITY - The maximum rated amount of weight, force, or pressure that a stamping press or sliding tool can safely exert at the end of its stroke.

CAPTIVE SCREW - A captive screw is a specialist product that cannot be wholly removed from a hole once installed. There is a 'captive' area under the head, usually at or below the minor diameter of the threaded area at the end of the screw. They are available in a range of head styles, but the key similarity surrounds each product is that they all host a reduced thread.

CARBIDE PRECIPITATION - Carbon that breaks loose form its bond with the stainless solution when material is heated between 800-1400 degrees. Under severe corrosive conditions it can result in extra oxidation and surface corrosion.

CARBON - Carbon adds strength to stainless steel, but also lowers corrosion resistance. The more carbon there is, the more chromium must be added, because carbon offsets 17 times its own weight in chromium to form carbides, thus reducing the chromium available for resisting corrosion

CARBON POTENTIAL - A measure of the ability of an environment containing active carbon to alter or maintain, under prescribed conditions, the carbon content of the steel exposed to it. In any particular environment, the carbon level attained will depend on such factors as temperature, time and steel composition.

CARBON RANGE - In steel specifications, the carbon range is the difference between the minimum and maximum amount of carbon acceptable. Carbon adds strength to stainless steel ,but also lowers corrosion resistance. The more carbon there is, the more chromium must be added, because carbon offsets 17 times its own weight in chromium to form carbides, thus reducing the chromium available for resisting corrosion.

CARBON RESTORATION - Replacing the carbon lost in the surface layer from previous processing by carburizing this layer to substantially restore the original carbon level.

CARBON STEEL - Steel which owes its properties (up to 1.2% carbon) chiefly to various percentages of carbon and is without substantial trace amounts of other alloying elements. Higher percentages of silicon and manganese may be added for composition control.

CARBONITRIDING - A case-hardening process in which a suitable ferrous material is heated above lower transformation temperature in a gaseous atmosphere of such composition as to cause simultaneous absorption of carbon and nitrogen by the surface and, by diffusion create a concentration gradient. The process is completed by cooling at a rate that produces the desired properties in the workpiece.

CARBURIATION & DECARBURIZATION - Testing for carburization and decarburization surface conditions in metals will determine the amount of carbon in a specimen. When a test is ordered for one of these conditions, both conditions will be apparent and both will be reported. Too much of either condition may adversely affect the safety and performance of the metal. This test method is not intended to address products which are intentionally carburization to achieve specific results. The testing method classifies, measures, and determines the existence of decarburization and carburization in the threaded section of hardened and tempered metals which have been heated to enable fabrication or to alter their mechanical properties.

CARBURIZING - Absorption and diffusion of carbon into solid ferrous alloys by heating, to a temperature usually above Ac3, in contact with a suitable carbonaceous material. A form of case hardening that produces a carbon gradient extending inward from the surface, enabling the surface layer to be hardened either by quenching directly from the carburizing temperature or by cooling to room temperature, then re-austenitizing and quenching.

CARBURIZING - Adding carbon to the surface of an iron alloy part by heating it to below the alloy's melting point (usually between 1,560 Degrees F and 1,740 Degrees F, then putting it in contact with carbon-rich solids, liquids, or gasses. This increases the metal's strength and makes the part's surface harder and more abrasion-resistant, but it also decreases the metal's toughness. Carburizing is usually done on finished parts

CASE - (1) The surface layer of an iron based alloy which as been made substantially harder than the interior by some form of hardening. (2) The container or holder of the inserts on either the punch or die side of the tooling.

CASE - (1) The surface layer of an iron-base alloy that has been suitably altered in composition and can be made substantially harder that the interior or core by a process of case hardening: and (2) the hardened surface layer of a piece of steel that is large enough to have a distinctly softer core or center.

CASE HARDENED - Carburizing, nitriding or cyaniding and subsequent heat treating produces a case-hardened fastener, which is a fastener of ferrous material having a surface harder than the core.

CASE HARDENING - A generic term covering several processes application to steel that change the chemical composition of the surface layer by absorption of carbon, nitrogen, or a mixture of the two and by diffusion, create a concentration gradient. The processes commonly used are carburizing and quench hardening; cyaniding; nitriding; and carbonitriding. The use of the applicable specific process name is preferred.

CASING (NAIL) - A wire nail with a slightly larger head than finish nails; often used for flooring and when concealment is desired.

CASSETTE - Also known as sub-bolster, die assembly, trim and pierce assembly. An assembly of top and bottom dies and/or tools of each forming station assembled into one unit.

CASSETTE - The individual punch holder or die holder on the large FORMAX Plus machines. A part of the tool changing system.

CAST (PROOF) - Any reproduction of a die cavity in any material, frequently lead, plaster or epoxy, used to confirm the exactness of the cavity. See Die Proof.

CAST-IN-PLACE ANCHOR - A headed bolt, stud or hooked bolt installed into formwork prior to placing concrete.

CASTELLATED - Having grooves or slots on its upper face.

CATASTROPHIC HAZARD - (1) A hazard that could result in a mishap causing fatal injury to personnel, and/or loss of one or more major elements of the flight vehicle or ground facility (2) A condition that may cause death or permanently disabling injury, major system or facility destruction on the ground, or loss of crew, major systems , or vehicle during the mission.

CATHODE - The material in a corrosive attack that attracts electrons from the anode.

CATHODE - In electrolysis, the electrode at which positive ions are discharged, negative ions are formed or other reducing reactions occur.

CATHODE EFFICIENCY - Current efficiency of a specified cathodic process.

CATHODE FILM - The think layer of solution which is in contact with the cathode and differs in composition from the bulk of a solution.

CATHODIC (DIRECT) CLEANING - Electrolytic cleaning in which the work piece is the cathode.

CATHODIC BARRIER PROTECTION - Method of fighting corrosion in which a plating metal is attached to the surface of a substrate material (e.g. fasteners). The plating metal is anodic to the substrate (thereby making the substrate cathodic) so that the plating metal will corrode first, thus protecting the substrate material. It is a method used to protect fasteners from galvanic corrosion.

CATION - A positively charged ion.

CAVITY, DIE - The machined recess in a die that gives the forging its shape.

CELLULAR MANUFACTURING - An approach in which manufacturing work centers (cells) have the total capability to produce an item or group of similar items.

CEMENTATION - The introduction of one or more elements into the outer portion of a metal object by means of diffusion at high temperature.

CEMENTATION - The process of introducing elements into the outer layer of metal objects by means of high-temperature diffusion.

CEMENTITE - This is a carbon rich steel also known as iron carbide (Fe3C). In carbon steel, it either forms from austenite while cooling or from martensite during tempering.

CENTER-LINE to EDGE DISTANCE - The minimum distance from the edge of a panel to the center of the mounting hole that a self-clinching fastener can be installed without causing a distortion or bulge in the panel.

CENTERING DISC - Used behind the punch holders on machines with punch rockers. It acts as a hardplate for the tooling and the centering block for the punch holders. Allows the punch holder to be removed from the punch rocker and re-installed back on center.

CENTRAL BURSTING - Also refers to the single internal burst that can occur at the junction of a head upset and the start of the shank.

CENTRIFUGAL CAPACITY(N) - A mathematical expression for determining the speed (in revolutions per minute, rpm) at which a retaining ring will lose cling on the groove.

CERTIFICATE OF COMPLIANCE (COC) - Certification stating that parts meet all required specifications it is being sold under.

CERTIFICATION - A procedure and action to verify in writing a process or material meets a set of applicable standards. This helps ensure consist products for both manufacturer and end users.

CETYL ALCOHOL - An organic, fatty alcohol applied to fasteners as a lubricant

CHAIN DIMENSIONING - Drafting practice which dimensions repetitive features from each other rather than a common datum

CHAMFER - (v) To bevel a sharp external edge. (n) A beveled edge.

CHAMFER - To break or remove sharp edges or corners of forging stock by means of straight angle tool or grinding wheel.

CHAMFER - The bevel on a corner that is at an angle to either side.

CHAMFER - An angle cut (typically 45 degrees) applied to an O.D. corner of a part to eliminate the sharp corner.

CHAMFER ANGLE - The angle of the chamfer measured from the normal to the axis of the fastener and generally specified in conjunction with either a length or a diameter.

CHAMFER POINT - A truncated cone point, the end of which is approximately flat and perpendicular to the fastener axis. Three points on threaded fasteners generally have point included angles of 45 to 90 degrees and a point diameter equal to or slightly less than minor diameter of the thread. This point is intended to facilitate entry of fasteners into holes at assembly.

CHARACTERISTIC DESIGN VALUE - The nominal strength for which there is 90% confidence that there is a 95% probability of the actual strength exceeding the nominal strength.

CHARPY IMPACT TEST - An impact test in which a specially V-notched specimen is broken by the impact of a falling pendulum. The energy absorbed in fracture is a measure of the impact strength or notch toughness of the sample.

CHARPY TEST - A test made to determine the notched toughness, or impact strength, or a material. The test gives the energy required to break a standard notched specimen supported at the two ends.

CHASING THREADS - Cutting screw threads by moving a tool along the axis of the work to be threaded.

CHECK - Crack in a die impression, generally due to forging pressure and/or excessive die temperature. Die blocks too hard for the depth of the die impression have a tendency to check or develop cracks in impression corners.

CHEESE HEAD - See Fillister Head

CHELATE COMPOUND - A compound in which the metal atom forms part of a ring-structure and is not readily ionized.

CHELATING AGENT - An organic compound capable of forming a chelate compound with a metal ion.

CHEMICAL ANALYSIS - Qualitative analysis consists of separating a substance into its component elements and identifying them, in quantitative analysis the proportion of all component elements are determined.

CHEMICAL ANALYSIS - Tests to identify the chemical composition of metals and alloys. Tests include Optical Emission Spectroscopy (OES), FTIR analysis, Energy Dispersive Spectroscopy (EDS), Carbon Sulfur combination determination, and trace metal analysis

CHEMICAL POLISHING - Immersion in a solution to improve the surface smoothness of a metal. (Not to be confused with bright dipping.)

CHEVRON - An internal burst defect on a forward extruded part. Usually occurs in multiples along the length of the forward extrusion, and is caused by multiple extrusion passes over the same section of the part.

CHIP - An unwanted piece of metal that is removed from a workpiece. Chips are formed when a tool cuts or grinds metal.

CHISEL POINT - Typically a horizontal knife edge added to the end of a kickout pin. The purpose is to keep the part from rotating during the kickout or insertion of a part into or from a die. Required when the formed part must be oriented between forming operations, The kickout pin is also keyed to the tooling to keep it from rotating.

CHISEL POINT - Reduces wood splitting; comprised of 2 sides; mostly used for pallet-making and manufacturing.

CHISEL POINT 45 DEGREE STUD - A full thread stud used to break the capsule of adhesives in an anchoring device to secure it in the base material.

CHOKE SLEEVE - A special kickout sleeve or punch sleeve with a restricted orifice to contain the slug after piercing.

CHOP - A die forging defect; metal sheared from a vertical surface and spread by the die over an adjoining horizontal surface.

CHROMATE - A secondary dipping process after plating increasing corrosion resistance, adding brilliance. It also can be colored. Standard clear chromate leave a bluish-white hue; other colors may be chosen, such as yellow, olive drab or black.

CHROMATE DIPS - Clear chromate dip is usually applied to all zinc plated parts unless otherwise requested. Olive Drab Dichromate - Electroplated work is dipped in solution of chrome, nitric and acetic acids and a dye. This produces additional corrosion resistance, and is thicker than standard chromate dips. Yellow Iridescent Dichromate - Electroplated are dipped in a solution of sodium dichromate, takes on surface film of basic chromium chromate which resists corrosion. Finish is yellow to brown appearance.

CHROMATING - Forming a conversion coating on a metal surface by means of a solution containing chromium compounds usually in the hexavalent form.

CHROME - A type of coating that provides corrosion resistance and aesthetically pleasing (or decorative) appearance.

CHROME - Chrome plating is applied in two methods. Hard-chrome deposits a thick layer of chrome to the fastener. This gives the part a very hard finish and superior wear resistance but does not offer much protection to corrosion. A nickel-chrome finish is achieved by applying a flash of chrome on top of nickel plating. This process offers resistance to tarnishing and corrosion.

CHROMIUM - Chromium, a blue-white metal is the most important element in providing corrosion resistance in stainless steel. By adding 12 percent chromium to ordinary steel, stainless steel is formed. Chromium offsets the corrosive effects of carbon found in steel and is the primary factor in the ability of the stainless to form a passive film on its surface providing corrosion resistance.

CHROMIUM, ELECTROPLATED - Bright blue-white, lustrous finish. Has relatively hard surface. Used for decorative purposes or to add wear resistance.

CHUCKING LUG - A lug or boss to the forging so that (on center) machining and forming can be performed with one setting or chucking; this lug is machined or cut away on the finished item.

CLAMP FORCE - The force between two components held together in a joint. Clamp force is typically imparted to a joint through threaded fasteners. Maintaining an appropriate amount of clamp force is critical to the functionality of any joint. Differs from preload in that preload is applied during assembly while clamp force may change after relaxation and elastic interactions have taken place.

CLAMP LOAD - The compression load induced in the joint by the installed fastener. The residual clamp load (or joint pre-tension) is the compressive load remaining in the joint after the fastener is installed. Higher clamp loads are experienced during fastener installation (pulling force).

CLAMP LOAD - Also called initial load or preload, is created when tension is applied on a bolt and results in equal force and measures of the compression of two parts. Typically measured in "pounds", a value of clamping force imparted by the elastic tension of the fastener in the assembled parts. It is commonly calculated as 75 percent of minimum proof load.

CLAMP MARKS - Slight indentations at the edge of one side of stock caused by pressure from turret press holding devices.

CLAMPING FORCE - The compressive force which a fastener exerts on the joint.

CLASS - Used in metric; class is a material designation equivalent to the US term Grade (ex. Class 10.9)

CLASS 1A/1B THREADS - These threads have a large tolerance and a wider allowance fit. A represents the external thread and B represents the internal thread.

CLASS 2/A/2B THREADS - The most common class of threads. They have a moderate tolerance that balances manufacturing costs and performance.

CLASS 3/A/3B THREADS - These threads are made to an extremely close tolerance and have no allowance. Used for higher-strength fasteners in safety-critical applications.

CLASS OF FIT - The Class of Fit is a measure of the degree of fit between mating internal and external threads. Three main Classes of Fit are defined for metric screw threads: FINE: This has a tolerance class 5H for internal threads and 4h for external threads. MEDIUM: This has a tolerance class of 6H for internal threads and 6g for external threads. COARSE: This has a tolerance class of 7H for internal threads and 8g for external threads. For Unified threads, a similar designation as for metric threads is used. The thread classes used are 1A, 2A, and 3A for external threads and 1B, 2B and 3B for internal threads.

CLASS OF FIT (Metric) - The Class of Fit is a measure of the degree of fit between mating internal and external threads. Three main Classes of Fit are defined for metric screw threads:

• FINE: This has a tolerance class of 5H for internal threads and 4h for external threads.
• MEDIUM: This has a tolerance class of 6H for internal threads and 6g for external threads.
• COARSE: This has a tolerance class of 7H for internal threads and 8g for external threads.

CLASS OF THREAD - Classes of threads are distinguished from each other by the amount of tolerance or tolerance and allowance specified. Classes 1A, 2A and 3A apply to external threads, and Classes 1B,2B and 3B apply to internal threads. Classes 2 and 3 apply to both external and internal threads. There is one other Class of thread, Class 5 Interference-fit for special applications.

CLEANING - The process of removing scale, oxides, or lubricant - acquired during heating for forging or heat treating - from the surface of the forging. See Blasting, Pickling, Tumbling.

CLEAR CHROMATE - Used on Zinc and Cadmium plated parts; very good to excellent corrosion resistance. Clear bright lustrous finish applied to zinc or cadmium plated surfaces for added corrosion protection.

CLEARANCE - An amount of space or distance between two objects.

CLEARANCE FIT - An internal and external thread design whose combination of allowances and tolerances allow for a free running assembly.

CLENCH - The ability of a fastener to draw together and hold together initially separated joint material components, during the installation process (i.e. 'gap closing' ability).

CLING - A value that signifies the amount of "interference fit" between a retaining ring and its groove.

CLIP MANUFACTURING - The act of utilizing various metal forming processes to create structural or decorative metal clips.

CLOCK SYSTEM - A system that identifies the strengths of nuts by dots or circle radius lines.

CLOSE ENDS - The end of the wire coil on a compression spring where it touches the next coil

CLOSE-TOLERANCE FORGING - One held to closer-than-conventional dimensional tolerance so that little or no machining is required after forging.

CLOSE-WOUND OR CLOSE-COILED (Spring Term) - Coiled with adjacent coils touching

CLOSED & GROUND ENDS (Spring Term) - (Also known as Squared & Ground) The ends of a compression spring where the pitch of the end coils is reduced to zero and the ends are ground square with the spring axis.

CLOSED & UNGROUND ENDS (Spring Term) - (Also known as Closed and Square ends, or Squared Ends) The ends of a compression spring where the pitch of the end coils is reduced to zero.

CLOSED AND GROUND ENDS - Where the end of the wire coil touches the next coil and is ground flat as to sit flat on a compression spring.

CLOSED DIE FORGING - The shaping of hot metal completely within the walls of cavities of two dies that come together to enclose the workpiece on all sides. The impression for the forging can be entirely in either die or divided between the top and bottom dies. Impression-die forging, often used interchangeably with the term closed-die forging, refers to a closed-die operation in which the dies contain a provision for controlling the flow of excess material, or flash, that is generated. By contrast,, in flashless forging, the material is deformed in a cavity that allows little or no escape of excess material. See Impression Forging.

CLOSED END - (1) the term used in the blind threaded insert industry to describe an internal threaded insert with metal enclosing the end of the thread opposite the head. (2) In self-clinching fastener industry this style of part is said to be blind or have blind thread. Closed end parts are used to prevent long screws from interfering with other components or for protecting the mating threads from corrosive environments.

CLOSED END - 1) The term used in the blind threaded insert industry to describe an internal threaded insert with metal enclosing the end of the thread opposite the head. 2) In the self-clinching fastener industry this style of part is said to be blind or have blind thread. Closed end parts are used to prevent long screws from interfering with odther components or for protecting the mating threads from corrosive environments.

CLOSING - Term applied to the operation of deforming the threads of tyep FE/LC/LK/UL nuts to provide prevailing thread lock.

CLOSING-IN - The forging operation that locally reduces diameters in hollow forgings.

CLOSURE, DIE - A term frequently used to mean variations in thickness of a forging.

CLUTCH DRIVE RECESS - There are two types of Clutch screw drives. Type A and Type G. Type A is known as the "Standard Clutch", resembles a bow tie , with a small circular "knot" at the center. Popular in the 1940 & 50a with GM cars and trucks and buses. Type G resembles a butterfly, and lacks the center "knot". This type of screw head is commonly used in the manufacture of mobile homes and RVs. The clutch head was designed to be driven with a flat-blade screwdriver as well as a clutch driver.

CLUTCH RECESS - Non-tapered recess gives skid proof straight driving without cam-out. Uses a clutch driver.

CNC LATHES (CNC) - These lathes can also CNC machine and CNC turn up to six parts at once. They, however, cannot carry as many spindles as CNC screw machine and are therefore not as versatile. They also do not work as well for mass production. Other types of screw machinery include mechanical screw machines, multi-spindles CNC screw machines, Swiss type screw machines, and roll machines.

CNC MACHINING - Computer Numerical Control machining uses computers to control and monitor the movements of a machine tool during the manufacturing process.

CNC SCREW MACHINES (CNC) - These machines can machine up to six parts at once, and they can multiple spindles at once. They are extremely useful for mass production applications. CNC screw machining and CNC turning can create more uniform, complex and precise parts.

CNF TRANSFER - An abbreviation for Cold Nut Former transfer. The transfer allows for the 180 degree rotation of parts between forming stations. With the addition of special units, the parts can be transferred straight across between stations as well. The fingers do not have cam controlled opening and closing so blanks are typically gripped on the maximum outside dimension and the forming punches passed through the fingers. Typically used for shot run nut type products.

COAP - An abbreviation for Change Over Assistance Package. This is a special die block and tool package for quick changeover. Removal of mechanical fasteners allow removal of the entire die block as a unit and the entire tool package as a unit.

COARSE THREAD - This thread type has a greater pitch and is more forgiving of thread nicks. Coarse threads have a greater resistance to thread stripping and are better for assemblies which encounter fatigue loading

COATING - The application of some material such as metal organic compound, etc. to the surface of a fastener. There are a variety of different types such as dip-spin, mechanical and hot dip galvanizing, powder coatings and spray-on coatings.

COEFFICIENT OF FRICTION - A dimensionless number representing the ratio of the friction force to normal force. Typically for threaded connections it is between 0.10 to 0.18 but can vary significantly depending upon the materials used and whether a lubricant has been used. In relation to threaded fasteners, the coefficient of friction can be further sub-divided into the coefficient of friction between the threads and the coefficient of friction under the nut face. There is in general a difference in values between the two coefficients due to typically the contact surfaces being different.

COEFFICIENT OF FRICTION - A dimensionless number representing the ratio of the friction force to normal force. Typically for threaded connections it is between 0.10 to 0.18 but can vary significantly depending upon the materials used and whether a lubricant has been used. In relation to threaded fasteners, the coefficient of friction can be further sub-divided into the coefficient of friction between the threads and the coefficient of friction under the nut face. There is in general a difference in values between the two coefficients due to typically the contact surfaces being different. For example, a zinc plated nut on a zinc plated bolts, the thread coefficient of friction would be due to zinc plating contacting zinc plating. The nut face coefficient of friction would be due to zinc plating contacting the joint surface finish.

COGGING - The reducing operation in which an ingot is worked into a billet by the use of a forging hammer or a forging press.

COIL FEEDING - A system where material is delivered to the stamping equipment from cylindrically wound sheets or strips.

COIN - To form to more exacting dimensions and shape by re-striking. The amount of forming is usually relatively small.

COIN- SLOT DRIVE - Coin-slot drives are so-called because of the curved bottom of the recess, which facilitates driving them with a suitable coin.

COINING - (1) A post-forging process-on hot or cold parts-used to attain closer tolerances or improved surfaces. (2) A closed-die squeezing operation in which all surfaces of a workpiece are confined or restrained, resulting in a well-defined imprint of the die on the work.

COINING - During this process, a technician places a piece of metal between a die and punch in a stamping machine, and then uses the tip of the punch to penetrate the material and bend it. This process is repeated to relieve internal stresses throughtout the component. When fixed, a coined material should not exhibit any spring-back effects.

COINING DIES - Dies in which the coining or sizing operation is performed.

COLD FINISHING - Changing the shape of or reducing the cross section of steel while cold- usually accomplished by rolling, drawing through a die, or turning.

COLD FLOW - Continued deformation of a material under stress.

COLD FORGING - Various forging processes conducted at or near ambient temperatures to produce metal components to close tolerances and net shape. These include bending, cold drawing, cold heading, coining, extrusion (forward or backward), punching, thread rolling and others.

COLD FORMING - The shaping of a metal at room temperature.

COLD HEADING - Forcing metal to flow cold into dies to form thicker sections and more less intricate shapes. The operation is performed in specialized machines, where the metal , in the form of a wire or bar stock, may be upset or headed in certain sections to a larger size and, if desired, may be extruded on other sections to a smaller diameter that the stock wire. Cold heading causes an increase tensile strength and hardness and a decrease in ductility. AKA, Cold Form or Cold Working.

COLD HEADING - Plastically deforming metal at ambient temperatures to increase the cross-sectional area of the stock (either solid bar or tubing) at one or more points along the longitudinal axis See Heading and Upsetting.

COLD HEADING STOCK - Stock material produced under closely controlled manufacturing and inspection methods to be suitable for heading and to be free from those defects causing fractures during heading.

COLD LAP - A flaw that results when a workpiece fails to fill the die cavity during the first forging. A seam is formed as subsequent dies force metal over this gap to leave a seam on the workpiece surface. See cold shut.

COLD SAW - Mechanical sawing machine used to produce cut pieces prior to the forging operation. Sawing is carried out on the material at ambient temperature.

COLD SHUT - Also known as lap or fold. A defect such as lap that forms whenever metal folds over itself during forging. This can occur where vertical and horizontal surfaces intersect.

COLD SHUT - A fissure or lap on a formed surface which has been closed without fusion during the forming process; the surface folds over on itself.

COLD SWAGING PROCESS - A method of reducing or forming steel or other material while cold, by drawing to a point or reducing the diameter, as may be required.

COLD SWILL - Washing in cold water.

COLD TREATMENT - Exposing to suitable subzero temperatures for the purpose of obtaining desired conditions or properties, such as dimensional or microstructural stability. When the treatment involves the transformation of retained austenite, it is usually followed by a tempering treatment.

COLD TRIMMING - Removing flash or excess metal from the forging in a trimming press when the forging is at room temperature.

COLD WORK - To deform metal stock while the metal is at ordinary room temperature. Altering the geometry of a metal component below the recrystallization temperature by plastic deformation. Processes include rolling, drawing, pressing, spinning, extruding and cold heading.

COLD WORKING - Permanent plastic deformation of a metal at a temperature below its recrystallization point - low enough to produce strain hardening. Usually, but not necessarily, conducted at room temperature. Also referred to as cold forming or cold forging. Contrast with hot working. This may change its shape, giving the metal more tensile strength and better machinability.

COLD-COINED FORGING - A forging that has been restruck cold in order to hold closer face distance tolerances, sharpen corners or outlines, reduce section thickness, flatten some particular surface, or, in non-heat-treatable alloys, increase hard-ness.

COLLAR - A raised ring or flange of material on the head or shank of a fastener.

COLLAR - A fastening component that is attached to a pin to clamp one or more pieces together and provide a permanent installation. Method of attachment may be by threading, swaging, forming or other means.

COLLAR CROPPER/SPLITTER - An installation tool attachment that removes collars from lockbolt fasteners.

COLOR PHOSPHATE COATINGS - Chemically produced color coating. Available in blue, green, red, purple, and other colors.

COLOR, CHROMATE FINISH - Olive drab, blue (used often for metric fasteners), bronze, red and other colors. A secondary dipping process after plating increasing corrosion resistance.

COLOURING OFF - Light final buffing

COLUMBIUM - A metal which may be added to chrome-nickel stainless steel to improve its welding and general heat-resistant qualities, by preventing carbide precipitation.

COLUMN (GAGING) - An air or electronic amplifier featuring a vertical bargraph display.

COMBINATION DRIVES - Some screw drives have heads designed to accommodate more than one kind of driver, sometimes referred to as combo-head or combi-head. The most common of these are a combination of a slotted/Phillips head for furniture drawers and combined slotted/Pozidriv for electrical switchgear or nicknamed "electrician's screws". The idea is that the first screwdriver out of the toolbox is used and the user does not have to waste valuable time searching for the correct driver. Their rise to popular use has been in spite of the fact that the head is weaker and neither a flat screwdriver or Pozidriv/Phillips screwdriver as appropriate is fully successful in driving these screw to the required torque.

COMBINATION PUNCH HOLDER - A special tool holder on a machine with a punch rocker. It allows for either a stationary or sliding tool. Can be used in either the cone or finish blow.

COMMERCIAL FASTENER - A fastener manufactured to published standards and stocked by manufacturers or distributors. The material, dimensions, features, and finish of commercial fasteners conform to the quality level generally recognized by manufacturers and users as the commercial quality.

COMMINGLING - A term used to describe the undesirable practice of mixing fasteners from different batches that are the same size and grade in the ssame container.

COMMON (NAIL) - A common construction wire nail with a disk-shaped head that is typically 3 to 4 times the diameter of the shank; common nails have larger shanks than box nails of the same size; for general interior and exterior construction, carpentry and wood framing

COMPARATOR - A device for inspecting screw threads and outlines by comparing them with a greatly enlarged standard chart.

COMPLETE HOLE FILL - Fasteners with this feature will expand to fill irregular, slotted, oversized, or misaligned holes.

COMPLETE THREAD - The length of completed thread is the length of that cross section of a threaded length having full form at both crest and root. Where there is a chamfer at the start of the thread not exceeding two pitches in length, it is included within the length of the complete thread. The thread length on the drawing shall be the gaging length or the length of threads having full form, i.e. the partial threads shall be outside or beyond the length specified. When designing threaded products, it is necessary to take cognizance of : (1) Such permissible length of chamfer and (2) the first two threads which by virtue of HI-LO gaging practice may exceed the product limits and which may be included within the length of complete thread. However, where the application is such as to require a minimum or maximum number, or length, of complete threads, the specifications shall so state. Similar specification is required for definite length of engagement.

COMPLEXING AGENT - A compound that will combine with metallic ions to form complex ions.

COMPOSITE MATERIAL FASTENERS - Fasteners designed for use in sandwich panel, honeycomb panel or other composite materials.

COMPOUND DIE - Tool used to pierce, form and blank a part at the same time, with one stroke of the press.

COMPRESSION FASTENER - A fastener which resists forces which tend to compress it.

COMPRESSION LOAD - The load which tends to compress or shorten the member. The value for compression strength may depend upon the degree of distortion.

COMPRESSION SPRING - A spring whose dimension, in the direction of the applied force, reduces under the action of that force.

COMPRESSION SPRING (Spring Term) - An open-coiled spring that offers resistance when compressed.

COMPRESSION STRENGTH - The max amount of stress a metal can withstand under compression without fracturing or becoming permanently deformed.

COMPUTER AIDED DESIGN (CAD) - CAD programs allow users to digitally design parts that are to be milled, 3D printed or rendered.

COMPUTER AIDED MACHING (CAM) - This is the software used to control machine tools during the manufacturing of work pieces.

CONCAVITY - A concave condition applicable to the width of any flat surface.

CONCEALED HEAD - A type of fastener which, when installed, is completely hidden when viewed from the reverse side. Installed into a blind hole.

CONCENTRIC THREAD™ - The concentric threads are most 2D shapes except a circle that is expanding in size and rotating on each layer. One of its models screws around a corner. Patent Issued

CONCENTRIC, CONCENTRICITY - Two surfaces of a fastener are concentric when they have a common center or axis. Concentricity is the term used to describe this condition.

CONCRETE BREAKOUT - Anchor failure from the deepest embedment of the anchor to the surface of the base material at an angle of about 35 degrees; referred to as the cone of concrete because the breakout will be triangular shaped or cone shaped.

CONCRETE COMPRESSIVE STRENGTH - The specified compressive load carrying capacity of concrete used in design, expressed in pounds per square inch (psi) or megapascals (MP)

CONCRETE SCREW - Tapcon® brand concrete screws that are made from carbon steel and the threads are hardened to allow them to tap base material such as concrete, brick or block. The threads are an alternating high/low design with diamond cut notches. Tapcons are plated with a Climaseal® coating for excellent rust resistance.

CONDITION A - Means that fasteners should be solution annealed

CONDITION B - Means strain hardened to meet certain minimum tensile requirements.

CONDITIONING HEAT TREATMENT - A preliminary heat treatment used to prepare a material for a desired reaction to a subsequent heat treatment. For the term to be meaningful, the treatment used must be specified.

CONE - (1) Typically the first preform upsetting operation with the top remaining the wire diameter but the base increasing in diameter creating a conical shaped section. (2) The term used to indicate the gathering of metal before forming.

CONE BLOW - The first blow struck in a single die 2 blow header. It gets its name from the shape of the first punch which is typically that of a frustum of a cone.

CONE POINT - A sharp conical point designed to perform perforating or aligning functions at assembly.

CONE PROOF LOAD - This is an axial applied force applied to a nut when it is seated on a cone shaped washer which has an included angle of 120 degrees. Failure in this test is usually due to the nut splitting. The intention of the test is to introduce a nut dilation operation which will assess the potential detrimental effects of surface discontinuities. This type of test is sometimes applied to nuts which are intended for high temperature service.

CONE PUNCH HOLDER - The tool holder for the first blow on a machine with a punch rocker

CONIC THREADS™ - The profiles of the mated conic threads are on the same plane perpendicular to their direction of travel. These are best suited for pipe threads. Patent Issued.

CONNECTION POINTS - The supporting points that connect the slide to the upper drivetrain of the stamping press.

CONSTANT PITCH - Threads which are designed for repeated assembly and disassembly. Regardless of the diameter, the pitch will always be the same for constant pitch threads. The most common version is the 8-thread series.

CONTACT PLATING - The deposition of a metal coating upon a basis metal, by immersing the latter in contact with another metal in a solution containing a compound of the metal to be deposited (Not to be confused with immersion plating)

CONTINUOS FLOW MANUFACTURING (CFM) - Descriptive of material moving one piece at a time, at a rate determined by the needs of the customer in a smooth and untierrupted sequence without WIP.

CONTINUOS-ON-DEMAD (CSD) - A mode of operation where the press is automatically run without interruption based on input from upstream or downstream processes. The press will run constantly until a signal is received to instruct it otherwise

CONTROL LENGTH - The linear amount of guide of a part in either a die or punch, It is used during the transfer finger analysis.

CONTROL METHODS - The control method should match the joint specifications and the quality assurance required. For most critical applications, microprocessor-based controllers can perform 100% inspection of the dynamic applied torque and collect statistical process-control data. Such methods can eliminate the need for secondary inspection processes.

CONTROLLED CLOSING FINGERS - Special transfer fingers with a stop to limit how far closed the fingers can go without a blank in the fingers. used when there are short cutoff blanks, short stepped parts, or where the fingers could be hit by the punch when the machine is cycled empty.

CONTROLLED COOLING - Cooling from an elevated temperature in a predetermined manner to avoid hardening, cracking, or excessive internal stresses, or to produce a desired microstructure.

CONVENTIONAL FORGING - A forging characterized by design complexity and tolerances that fall within the broad range of general forging practice.

CONVERSION COATING - A coating consisting of a compound of the surface metal produced by chemical or electrochemical treatment. Example: chromate films on zinc or cadmium or oxide films on steel. Note: (Anodizeu coatings on aluminum or magnesium while satisfying these definitions are not normally conversion coatings.)

COOLING CURVE - A curve showing the relation between time and temperature during the cooling of a material.

COOLING CURVE - A curve showing the relation between time and temperature during the cooling of a material.

COPPER - Metallic element having atomic number 29. Possesses good corrosion resistance and ductility. Copper is nonmagnetic, malleable and has excellent electrical and thermal conductivity. Comes in a variety of colors. Shortcomings include a low strength-to-weight ratio and a loss of strength at low temperatures. Brass and silicon bronze are composed mainly of copper and gain their strength from the addition of other metals such as silicon.

COPPER STEEL - When any minimum copper content is specified, the steel is classed as copper steel. The copper is added to enhance corrosion resistance of the steel.

COPPER, ELECTROPLATED - Used for nickel and chromium plate undercoat. Can be blackened and relieved to obtain antique, statuary and Venetian finishes.

CORE - (1) The interior portion of an iron-base alloy that after case hardening is substantially softer that the surface layer or case; and (2) the relatively soft central portion of certain hardened tool steels.

CORE BOLT - The externally threaded, central part of a blind fastener.

CORNER - Three surfaces meeting at one point

CORNER RADIUS - Outside Radius

CORROSION - Gradual chemical or electro-chemical attack on a metal by atmosphere, moisture, or other agents. The wearing away or alteration of a metal by an electro-chemical reaction or by a direct chemical attack within its envirnoment.

CORROSION CRACKING, STRESS - A condition where cracks are induced and propagated in a fastener under combined effects of stress and corrosive environments.

CORROSION RESISTANCE - This describes the ability of a fastener to resist corrosion under specified conditions.

CORROSION, CONCENTRATION-CELL - Corrosion that begins in small cracks and crevices when two or more areas of a metal surface are in contact with different concentrations of the same solution. It only needs one metal and one electrolyte.

CORROSION, ELECTROCHEMICAL - Occurs when an electrical current flow from the metal of higher potential toward the lower. Exclusive to metals. Examples include galvanic corrosion and pitting corrosion.

CORROSION, GALVANIC - Corrosion involving two dissimilar metals in the presence of an electrolyte. The more active (anodic) of the two metals sacrifices its ions to the less active, thereby causing breakdown in the active metal.

CORROSION, PITTING - Localized corrosion in which a small bubble of air gets trapped on the surface of the metal. This bubble deprives the metal's surface of fresh oxygen supply, causing that area to become anodic. The change in the reactivity of the metal causes the formation of small, sometimes deep, pits. Also called Cavitation Corrosion.

COUNTER BALANCE - A system that counteracts the mass of the slide, slide attachments, and drive members. The counterbalancing force - provided by pneumatic cylinders - helps to eliminate force reversal and shock loading at the end of the press stroke.

COUNTERBLOW FORGING - One made by equipment incorporating two opposed rams, which simultaneously strike repeated blows on the workpiece.

COUNTERBLOW FORGING EQUIPMENT - A category of forging equipment in which two opposed rams are activated simultaneously, striking repeated blows on the workpiece at a midway point. Action is vertical or horizontal.

COUNTERBORE - (v) To enlarge a hole to a given depth. (n) (1) The cylindrical enlargement of the end of a drilled or bored hole. (2) A cutting tool for counterboring, having a piloted end the size of the drilled hole.

COUNTERBORING - The process of enlarging for part of its depth a hole previously formed and providing a shoulder at the bottom of the enlarged hole. Special tools called counterbores are generally used for this operation.

COUNTERBORING - Machining or coining operation to generate a cylindrical flat-bottomed hole.

COUNTERSINKING - The process of beveling or flaring (typically 30 to 60 degrees) the end of a hole. Holes in which countersunk head type fasteners are to be used must be countersunk to provide a mating bearing surface.

COUNTERSINKING - Machining or coining operation to generate a conical angle on a hole.

COUNTERSUNK - An internal chamfer. Also refers to a head style that is reduced to a flat head so the screw or bolt can be placed flush in the material.

COUNTERSUNK HEAD - A head, the underside of which is beveled to fit a flaring hole, such as a flat head or an oval head. The bearing surface of other types of heads is generally perpendicular to the body axis.

COUNTERSUNK HEAD - A style of blind threaded insert with an angle, typically 100 degrees included, on the shank side of the head. If a proper size countersunk is applied to the mounting hole, this style of part will be flush in the panel in the head side after installation.

COVERING POWER - The ability of an electroplating solution under a given set of conditions to deposit metal on the surfaces or recesses or deep holes. (To be distinguished from throwing power). Critical current density (in electroplating): current density above or below which new and sometimes undesirable reactions occur.

CPM - An event oriented, project planning technique meaning critical path method.

CPVC (PLASTICS) - Chlorinating PVC results in a polymer that has all of PVC's good qualities, plus improved fire retardance, weatherability, a higher maxiumum working temperature and light-fastness.

CRACK - A clean, crystalline fracture which passes through or across the grain boundaries without inclusion of foreign elements.

CREEP - Plastic deformation or flow of metals held for long periods of time at stresses lower than normal yield strength. Especially important if temperatures of stressing are near recrystallization temperature of the metal. Permanent deformation of the material is caused by time, temperature, and pressure.

CREEP - Creep is deformation with time when a part is subjected to constant stress. Metals creep can occur at elevated temperature however with gasket materials it can occur at normal ambient temperatures. Creep resistance is an important property of gasket materials. Gasket materials are designed to flow under stress to fill any irregularities in the flange surface. The amount of creep sustained tends to increase with temperature. However once the tightening is completed it is important that no further flow occurs since such deformation will lead to a reduction in bolt extension and subsequently the stress acting on the gasket. If this stress is reduced to below a certain minimum, which depends upon the type and construction of the gasket and the opening temperature, a high rate of leakage can be anticipated to occur.

CREEP - The change in length of a spring when subjected to a constant force.

CREEP RANGE - Range of tension and temperature in which a material starts to experience creep,

CREEP STRENGTH - The maximum stress which can be applied to steel at a specified temperature without causing more than a specified percentage increase in length in a specified time.

CRES - Corrosion resistant steel (usually refer to 18-8 or 316 stainless steel)

CREST - That surface of the thread which joins the flanks of the thread and is farthest from the cylinder or cone from which the thread projects. For external threads, the crest is at the major diameter. For internal threads, the crest is at the minor diameter.

CREST -TO- CREST - A term used to identify a Flat Wave Compression spring in a "Series" configuration, having a sinusoidal waveform. The wave contour in each 360 degree turn provides a peak to valley relationship that decreases spring rate proportionally to the number of turns.

CREST CLEARANCE - As in a thread assembly, the distance, measured perpendicular to the axis, between the crest of a thread and the root of its mating thread.

CREST TRUNCATION - The crest truncation of a thread is the distance measured perpendicular to the axis, between the sharp crest (or crest apex) and the cylinder or cone bounds the crest.

CREVICE CORROSION - Refers to joints and crevices in a fastener assembly where lack of oxygen caused by limited space of by surface grease prevents the passive film on stainless from forming.

CRIMP LOCKING FEATURE - A squeezed portion of an internally threaded fastener that is used to prevent a mating screw from backing out due to vibration.

CRIMPING - The process of joining two pieces of metal together by deforming one of them such that it clamps or grips the other.

CRITICAL EDGE DISTANCE - The required distance from an unsupported edge of concrete to meet the maximum holding values.

CRITICAL HAZARD - A condition that may cause severe injury or occupational illness, or major property damage to facilities systems, or flight hardware.

CRITICAL SPACING - The required distance between anchors to meet the maximum holding values.

CRITICAL TEMPERATURE RANGE - Synonymous with Transformation Range which is preferred.

CROSS DRILLED - A fastener having one or more holes on the head or shank at right angles to, and normally intersecting, the axis of the fastener.

CROSS FORGING - Preliminary working of forging stock in alternate planes, usually on flat dies, to develop mechanical properties, particularly in the center portions of heavy sections.

CROSS SLOT - General term used to describe the head impression for driving a screw. Varieties include flat blade, Phillips, etc.

CROSS SLOTTED - Multiple slots are decorative and provide functional driving surfaces for many product styles and types.

CROWFOOT NUTRUNNER TOOL - Crowfoot nutrunners use special tool geometries to access hard-to-reah applications where more conventional tools won't fit. Gear-driven heads provide high levels of torque control. Special head designs can solve most demanding assembly problems.

CROWN - A spherical protrusion at the top of a fastener head

CROWN (STAPLE ANATOMY) - Crown - Spans the width of the staple

CRUCIFORM DRIVES - A cross shape drive recess for example the Phillips Drive or Pozidriv Drive recess.

CRYOGENIC TREATMENT (Cold treatment) - Treatment carried out after quenching to transform retained austenite into martensite, involving cooling and holding at a temperature below ambient.

CRYPGENIC (COLD TREATMENT) - Treatment carried out after quenching to transform retained austenite into martensite, involving cooling and holding at a temperature below ambient.

CTP POINT® - CTP Point is designed to prevent cross threading.

CTQ TREE - A tool to translate initial customer requirements into numerical or quantified needs for a product service.

CTS (GAGING) - Refers to air tooling designed to measure Close-To-Shoulder. As an example, an air plug used to measure counterbores. Removal of front center post on air plugs below 2.510" becomes a blind hole design.

CUMULATIVE TOLERANCE - Progressive accumulation of tolerances resulting from multiple operations or assembly of multiple parts.

CUP POINT - A point in the form of a cone, commonly having an included angle of 90 degrees, with a conical depression in the end commonly having an included angle of 118 degrees. The contact area is a circular ridge which has considerable holding power with slight penetration; applied to set screw generally.

CURE TIME - The elapsed time required for an adhesive anchor to develop its ultimate carrying capacity.

CURLING - The process of forming the edges of sheet metal into a circular cross-section by bending it around a shell or tube.

CURLING - Curling is a technique wherein a hollow and circular roll is introduced to the component. The curl is stronger than the rest of the component and safer to handle.

CURRENT DENSITY - Current expressed in amperes per unit area.

CURRENT EFFICIENCY - The proportion, usually expressed as a percentage, of the current that is effective in carrying out a given process in accordance with Faraday's law.

CUSTOM ASSEMBLIES - Components put together based on a customer's unique specifications using standard or non-standard parts and techniques.

CUSTOM METAL STAMPING DIE - A stamping die specially created for the production of customized, non-standard metal parts and components.

CUSTOM METAL STAMPINGS - Non-standard metal parts or components produced to customer-specific requirements by the action of a press operation or series of operations.

CUT POINT - The Type 17 or "gash" point helps drive the screw through the toughest woods without pre-drilling.

CUT THREAD - A thread produced by removing material from the surface with a form cutting tool.

CUTOFF - A blank is cut of from a coil. The diameter and length of the cut-off relates to the product diameter, finished bolt length and head size. The raw material is carbon alloy steel meeting the requirements of SAE and ASTM specifications for Hex Head Cap Screws and Bolts. The raw material has been pickled, annealed and coated prior to the manufacturing process. Also see Blank

CUTTER - The moving tooling component of the cutoff mechanism. It most often contains a hardened insert to extend the life of the cutting edge.

CUTTING TOOL - A device made of hard, tough material that is used to remove metal by creating chips.

CVD - An abbreviation for Chemical Vapor Deposition. This process is used to add a wear resistant coating to some tooling components, Commonly referred to as HOT process.

CYANIDING - A process of case hardening of an iron-base alloy be the simultaneous absorption of carbon and nitrogen by heating in a cyanide salt. Cyaniding is usually followed by quenching to produce a hard case.

CYCLE TIME - The normal time to complete a product or service operation. This is not the same as Takt Time.

CYLINDER - A solid, three dimensional shape with circular ends and straight sides.