Technical Resources

ABRASIVE: A material that penetrates and cuts a material that is softer than itself. It may be natural (  emery, corundum and diamonds) or man – made (silicon corundum , aluminum oxide).

ABSOLUTE ACCURACY: Accuracy as measured from a specified reference zero.

ABSOLUTE ZERO: - 273.16 deg. Centigrade (- 459.69 deg. Fahrenheit).

ACCURATE: Made within the tolerances allowed.

ACME THREAD: Similar in form to the square thread in that the top and bottom of the thread is flat; however, the sides have a 29 deg. Included angle. The Acme thread is used for feed and adjusting screws on machine tools.

ACUTE ANGLE: An angle of less than 90 deg.

ADDENDUM: That portions of the gear tooth that project above or outside of the pitch circle.

ADDRESS: Means of identifying information or a location in a control system.

ALIGN: Adjusting to given points.

ALLOWANCE: The limits permitted for satisfactory performance of the machined parts.

ALLOY: A mixture of two or more metals fused or melted together to from a new metal.

AMPLIFIER: A device or system which provides an output that is different in magnitude from the control output.

ANALOG: The presentation of a variable by physical quantity in a defined relationship; for example, a dial indication of pressure.

ANGLE PLATE: A precisely made tool of cast iron, steel or granite that is used to hold work in a vertical position for layout or machining. Faces are at right angles (90 deg.) and may have slotted openings for easier mounting of the work or clamping to the machine tool table.

ANNEALING: The process of heating metal to a given temperature (the exact temperature and the period the temperature is held depends upon the composition of the metal being annealed) and cooling it slowly to remove stresses and induce softness.

ANODIZING: A  process for applying an oxide coating to aluminum. It is done electrolytic ally in an acid solution with equipment similar to that used for electroplating. The technique can be varied to produce a light colored, porous coating that can be dyed in a variety of colors to a harder and nonporous coating for protection against corrosion.

APRON: A covering plate or casting that encloses and protects a mechanism. The portion of the lathe carriage that contains the gears, clutches and levers for moving the carriage by hand and power feed.

ARBOR:  A  shaft or spindle for holding cutting tools.

ASSEMBLY: A unit fitted together from manufactured ports. A machine tool may comprise several assemblies.

AUTOMATION: An industrial technique whereby mechanical labor and mechanical control are substituted for human labor and human control. Basically an extension and a refinement of mass production.

AXIS: The center line, real or imaginary, passing through an object abut which it could rotate. A point of reference.

BACK GEARS: Gears fitted to belt driven machine tools to increase the number of spindle speeds. Used to slow the spindle speed of the lathe for cutting threads, knurling and for making heavy roughing cuts.

BACKLASH: Lost motion (play) in moving parts, such as thread in a nut or in the teeth of meshing gears.

BED: One of the principal parts of a machine tool It contains ways or bearing surfaces that support and guide the work or cutting tool.

BERYLLIUM: A metal that weighs almost 80 percent less than steel, yet offers virtually equal strength characteristics. It is easy to machine but is brittle. Used in missiles and aircraft where weight is critical and in nuclear reactors. One of the “exotic” metals.

BEVEL: The angle formed by a line or a surface that is not at right angles to another  line or surface.

BINARY CODE: A code in which each allowable position has one of two possible states. A common symbolism for binary states is 0 and 1.

BISTABLE: Elements which have two output possibilities, and which will hold a given condition until switched.

BIT: An abbreviation of “binary digit.” A single character of a language employing exactly two distinct kinds of characters.

BLANKING: A stamping operation in which a die is used to shear or cut a desired shape from flat sheets or strips of metal.

BLOCK: A word or group of words considered as a unit and separated from other such units by an END OF BLOCK character.

BLOWHOLE: A hole produced in a casting when gases are entrapped during the pouring operation.

BRAZING: Joining metals by the fusion of non-ferrous alloys that have melting temperatures above 800 deg. F. but lower than the metals being joined.

BRITTLENESS: In some respects the opposite of toughness. The characteristics that cause metal to break easily

BUFFING: The process of bringing out the luster of metals. Buffing is accomplished by using cloth wheels, usually cotton or muslin discs sewed together , and  Tripoli compound. Proper wheel speed depends on the size of the wheel.

BURNISHING: The process of finishing a metals surface by compressing its surface. Often done by tumbling the work with steel balls.

BURR: The sharp edge remaining on the metals after cutting , stamping or machining. The burr can be dangerous if not removed.

BUSHING: A bearing for a revolving shaft. A hardened steel tube used on jigs to guide the drills and reamers.

CAM:  A rotating or sliding element that, because of the curvature if its driving surface, imparts complicated motions to the followers or driven elements of the machine tool.

CARBURIZING: A process that introduces carbon to the surface of steel by heating the metal below its melting temperature in contact with carbonaceous solids, liquids, or gases and holding at that temperature for a predetermined time after which the piece is quenched.

CASE HARDENING: A process of surface hardening iron base alloys so that the surface layer or case is made substantially harder than the interior or core. Typical case hardening processes are carburizing, cyaniding and nitriding.

CASTING: An object made by pouring molten metal into a mold

CAT HEAD: A sleeve or collar which fits over out-of –round, or irregular shaped work permitting it to be supported in a steady rest. The work is centered in the act headed by using the adjusting screws located around its circumference.

CENTER, DEAD: A stationary center

CENTER LINE: A line used to indicate an axis of a symmetrical part. The center line consists of a series of long and short dashes.

CENTRE LIVE: A rotating center.

CENTRIFUGAL CASTING: A casting technique in which the mold is rotated during pouring and solidification of the metal. It produces a casting with certain desirable characteristics.

CERMENTS:  A combination of ceramics and metals that is finding increased use of high temperature applications. Resistance to high temperatures and wear indicates great promise as a super high-speed cutting tool.

 CHAD: The pieces of material that are removed when punching holes in tape.

CHARACTER: One of a set of elementary marks or events which may be combined to express information.

CHASER: A thread cutting tool that fits into a die head used on a turret lathe or screw machine. Usually a hardened steel plate with several teeth of the correct pitch cut into it. Three or four chasers are used in a die head.

CHASING THREADS: Cutting threads on a machine tool.

CHATTER: Vibrations caused by the cutting tool springing away from the work. It produces small ridges on the machined surface,

CHEMICAL MILLING: Controlled removal of metal by chemicals rather than by conventional machining methods.

CHIP BREAKER: A small groove ground on the top of the cutting tool, near the cutting edge, to break the chips into small sections.

CHUCK: A device to hold work or cutting tools on a machine tool.

CIRCULAR PITCH: The distance  from the center of one gear tooth to the center of the next tooth measured on the pitch circle.

CLEARANCE: The distance by which one object clears another object.

CLIMB MILLING: Feeding work into the milling cutter in the same direction it rotates.

CLOCKWISE: From left to right in a circular motion. The direction clock hands move.

CODE: A system of signals or characters and rules for their interpretation. For punched or magnetic tape or cards; a predetermined arrangement of possible locations of holes or magnetized areas and rules for interpreting the various possible patterns.

COINING: The process that impresses the image or characters on the die and punch onto a plain metal surface.

COLD HEADING: An operation in which metal is worked cold.

COLOR HARDEN: A hardening technique usually done for appearance only.

COLOR TEMPER: Using the color range steel passes through when heated to determine the proper degree of hardness.

CONCAVE SURFACE: A  curved depression in the surface of an object.

CONCENTRIC: Having a common center.

CONE PULLEY: A one- piece pulley having two or more diameters.

CONTINUOUS CASTING: A casting technique in which the ingot is continuously solidified while it is being poured. The length of the casting is not determined by mild dimensions.

CONTOUR: The outline of an object.

CONTOUR CONTROL SYSTEM: A system in which the cutting path can result from the coordinated, simultaneous motion of two or more axes.

CONTROL: A signal received at system input, used as intelligence to produce to produce a modification in output.

CONVENTIONAL: Not original, customary , or traditional.

CONVEX SURFACE: A rounded surface on an object.

COOLANT: A fluid or gas used to cool cutting edge of a tool to prevent it from burning up during the machining operation.

CORE: A body of sand or other material that is formed to a desired shape and placed in a mold to produce a cavity or opening in a casting.

COUNTER BORE: Enlarging a hole to a given depth and diameter.

COUNTERCLOCKWISE: From right to left in a circular motion.

COUNTERSINK: Chamfering a hole to receive a flat head screw.

CRYOGENICS: The study and development of extremely low temperature processes, techniques and equipment.

CUTTING FLUID: A liquid used to cool and lubricate the cutting tool to improve the quality of the surface finish.

CYANIDING: A process of case hardening a ferrous alloy by heating in molten cyanide causing the metal to absorb carbon.

DEAD BAND: The range through which an input can be varied without initiating response.

DECARBURIZING: The process of removing carbon from metals.

DEDENDUM: The portion of the gear tooth between the pitch circle and the root circle, and is equal to the addendum plus the clearance.

DEMAGNETIZING: The removal of magnetism from a piece held in a magnet chuck.

DIE: A tool used to cut external threads. Also , a tool used to impart a desired shape to a piece of metal.

DIE CASTING: A  method of casting metal under pressure by injecting it into the metal dies of a die casting machine.

DIE CAVITY: A  hollow space inside a die where metal solidifies to from a casting.

DIE CHASERS: See CHASER.

DIE STOCK: The handle for holding a threading die.

DIVIDING  HEAD: A machine tool attachment for accurate spacing of holes, slots, gear teeth and flutes. When geared to the table lead screw, it can be used to machine spirals.

DOG: A projecting piece on the side of machine tool  worktable to trip the automatic feed mechanism off or for reverse travel.

DOG, LATHE: A device for clamping work so that it can be machined between centers.

DRAFT: The clearance on a pattern that allows easy withdrawal of the patter from the mold.

DRIFT: A tapered piece of flat steel used to separate tapered shank tools from sleeves, sockets or machine tool spindles.

DRILLING: Cutting round holes by use of a cutting tool sharpened on its point.

DRILL ROD: A carbon steel rod accurately and smoothly ground to size. Available in a large range of sizes.

DRIVE FIT: Using force or pressure to fit two pieces together. One of several classes of fits.

DROP FORGING: A forming operation, usually done under impact, that compresses the metal in dies designed to produce the desired shape.

DUCTILITY: The property of a metal that permits permanent deformation by hammering, rolling and drawing without breaking or fracturing.

ECCENTRIC: Not on a common  center. A device that converts rotary motion into a reciprocating (back and forth) motion.

ELECTROPLATING: A plating process accomplished by passing an electric current from an anode (usually made of the plating material) to the work, through an electrolyte containing salts of the plating metal in solution.

EMERY : A natural abrasive.

END OF BLOCK SIGNAL : A symbol or indicator that defines the end of one block of data.

EXPANSION FIT: The reverse of shrink fit. The piece to be fitted is placed in liquid nitrogen or dry ice until it shrinks enough to fit into the mating piece. Interference develops between the fitted pieces as the cooled piece expands.

EZY-OUT: A tool for removing broken bolts and studs from a hole. It is made in several sizes.

FACE: To make a flat surface by machining.

FACEPLATE: A circular plate that fits to the head stock spindle and drives or carries work to be machined.

FATIGUE: The tendency for metal to break or fracture under repeated or fluctuating stresses.

FERROUS: Denotes family of metals in which iron is the major ingredient.

FILLET: The curved surface that connects two surfaces that from an angle.

FIT: The clearance or interference between two matting parts. There are several classes of fits.

FIXTURE: A device for holding work in a machine tool. IT DOES NOT GUIDE THE CUTTING TOOL.

FLAME  HARDEN: A metal of surface hardening steel by rapidly heating the surface with the flame of an oxyacetylene torch, and quenching.

FLASH: A thin fin of metal formed at the parting line of a forging or casting where a small portion of metal is forced out between the edges of the die.

FLASK: A wooden or metal from consisting of a cope (the top portion) and a drag (the bottom portion) used to hold the sand that forms the mold.

FLIP-FLOP: A  bitable subsystem which will alternate from one output to another upon receipt of correctly phased input signals.

FLOTURN  PROCESS: Another term for shear spinning.

FLOW: A quantity passing a point per unit of time . in pneumatics, is commonly represented by C F M, or cubic feet per minute.

FLUIDICS: Control systems wherein a liquid or gas flows through intricate and precise channels, with in a solid component or circuit, to perform logic, computation and control functions for hydraulic and pneumatic equipment.

FLUORESCENT PENETRANT INSPECTION: A nondestructive testing technique. An oil base penetrant is sprayed on the work and is drawn into every crack and flaw. The surface is rinsed with solvent to remove excess penetrant. After developing, the surface is viewed under a “black light”. Defects glow with fluorescent brilliance.

FLUTE: A groove machined in a cutting tool to facilitate easy chip removal and to permit cutting fluid to reach the cutting point.

FLUX: The fusible material used in brazing and welding to dissolve and facilitate removal of oxides and other undesirable substances.

FLY CUTTER: A single point tool fitted in an arbor. Inexpensive to make, but is relatively inefficient  because only one point does the cutting.

FORCE FIT: The interference between the two mating parts is sufficient to require force to press the pieces together. The parts are considered permanently assembled.

FORGE: To from metal with heat and / or pressure.

FORMING: The operations or steps necessary to shape metal to a desired form.  The change does not intentionally change the thickness of the metal. .

FREE FIT: Used when tolerances are liberal . Clearance is sufficient to permit a shaft to run freely without binding or overheating when properly lubricated.

GAGE: A tool used for checking metal parts to determine whether they are made within specified limits.

GANG MILLING: Using two or more milling cutters to machine several surfaces at one time.

GATE: The point where molten metal enters the mold cavity .Also (FLUIDICS), a device or circuit which allows passage of a signal only if certain control requirement have been satisfied.

GEARS :Toothed wheels that transmit rotary motion from one shaft to another shaft without slippage.

GIB: A wedge-shaped strip that can be adjusted to maintain a proper fit of movable surface of a machine tool.

GRADUATE :To divide into equal parts by engraving or cutting lines or graduations into metal.

GRADUATIONS :The lines that indicate points of measurement on measuring tools and machine dials.

GUERIN PROCESS: A method of forming metal sheet in which the metal is forced to conform to the shape of a male die by the application of force to a confined rubber pad.

HALF NUTS: The mechanism that locks lathe carriage to the lead screw for the purpose of cutting threads.

HARDENING: The heating and quenching of certain iron- base alloys for the purpose of producing a hardness superior to that of the untreated material.

HARDNESS TESTING: Techniques used to determine the degree of hardness of heat- treated material.

HEAT TREATMENT: The careful application of a combination of heating and cooling cycles to a metal or alloy in the solid state to bring about certain desirable conditions, such as hardness and toughness.

HELICAL GEARS: Gears with the teeth cut at some angle, other than at right angles, to the gear face permitting two or more teeth to be engaged at all times. Their operation is smoother and not as noisy as the operation of spur gears.

HELIX: The path a point generates as it moves at a fixed rate of advance on the surface of a cylinder, such as screw threads or the flutes on a twist drill.

HIGH ENERGY RATE FORMING: A metal forming technique involving the release of a high energy such as explosives, electrical or pneumatic mechanical.

HOB: A special type gear cutter designed to cut gear teeth on a continuous basis.

HOBBING: Cutting gear teeth with a hob. The gear blank and hob rotate together as in mesh during the cutting operation.

HONING: A process used to produce an extremely fine surface finish on an object after the grinding operation. Honing permits a closer fit on critical parts. Abrasive blocks are forced against the work surface under very light spring pressure in a rotary motion and at the same time moved back and forth. The area is flooded with cutting fluid. Honing is an expensive operation.

HYDRO FORM: A method of forming parts in rubber under accurately controlled fluid pressure. The metal is formed over a movable male die in a flexible diaphragm.

HYDRO SPIN: Another name for shear spinning.

I D: Abbreviation for inside diameter.

IDLER GEAR: A gear or gears placed between two other gears to transfer motion from one to the other without changing the direction of rotation or the ratio between them.

IMPEDANCE: A total opposition to circuit flow, represented by resistance, capacitance, and inductance, combined to a resultant.

INDEPENDENT CHUCK: A chuck in which each jaw can be moved independently of the other jaws.

INDEXING: The term used to describe the correct spacing of holes, slots, etc., on the periphery of a cylindrical piece using a dividing or indexing head.

INDICATOR: A sensitive instrument capable of measuring slight variations when testing the trueness of  work, machines or machine attachments.

INSERTED TOOTH CUTTER: A milling cutter with teeth that can be replaced when they become damaged or worn rather than replacing the entire cutter.

INSPECTION: The measuring and checking of finished parts to determine whether they have been made to specifications.

INTERCHANGEABLE: Refers to a part that has been made to specific dimensions and tolerances and is capable of being fitted in a mechanism in place of a similarly made part.

INVESTMENT CASTING: A process that involves making a wax, plastic, or even a frozen  mercury pattern, surrounding it with a wet refractory material, melting or burning the pattern after the investment material has dried and set, and finally pouring metal (usually under air or centrifugal pressure) into the cavity.

JARNO TAPER: A standard taper of 0.600 in. per foot. Used on machine tools.

JIG: A device that holds the work in position and positions and guides the cutting tool.

JO – BLOCK: Precisely made steel blocks used by industry as a standard of measurement. They are made in a range of sizes and with a dimensional accuracy of  ±0.000002 (two millionths) inch, with  a flatness and parallelism of ±0.000003 (three millionths) inch.

KEY: A small piece of metal imbedded partially in the shaft and partially in the hub to prevent rotation of the gear or pulley on the shaft.

KEY WAY: The slot or recess in the shaft that holds the key.

KNEE: The unit that supports the saddle and table of a column and knee- type milling machine.

KNURLING: The operation that presses grooved, hardened steel wheels (knurls) into the surface of cylindrical work, rotating in the lathe, to produce rows of uniformly spaced serrations which provide a better grip, or for decorative purposes.

LAND: Metal left between flutes or grooves in drills, reamers, taps and other cutting tools.

LAPPING: The process of finishing surfaces with a very fine abrasive, like diamond dust or abrasive flours.

LARD OIL: A cutting oil made from animal fats. It is often mixed with mineral oils that improve the lubricating qualities.

LAY OUT: To locate and scribe points for machining and forming operations.

LEAD: The distance a nut will advance on a screw in one revolution.

LEAD SCREW: The long precision screw on the front of the lathe bed that is geared to the spindle to transmit motion to the carriage for thread cutting.

LONGITUDINAL MOVEMENT: Lengthwise movement.

MACHINABILITY: The characteristic of a material that describes the ease or difficulty of machining it.

MACHINABILITY INDEX: The table that indicates the degree of ease or difficulty of machining a material. It is based on the machining characteristics of a common steel (AISI B1112= 100). Magnesium alloy (Mach inability index = 500 to 2000) is relatively easy to machine. Tool steel (Mach inability index = 34) is difficult to machine.

MACHINE  TOOL: The name given to that class of machines which, taken as a group, can reproduce themselves.

MACHINIST: A person who is skilled in the use of machine tools and is capable of making complex machine setups.

MAGNAFLUX: A nondestructive inspection technique that makes use of a magnetic field and magnetic particles to locate flaws in materials.

MAGNAGLO: See FLUORESCENT PENETRANT IN SECTION. For use on magnetic materials only.

MAGNETIC CHUCK: A work – holding device that uses magnetic fields to hold work for machining (grinding).

MAJOR DIAMETER: The largest diameter of a thread measured perpendicular to the axis.

MALLEABILITY: The property of metal that determines its ease in ease in being shaped when subjected to mechanical working (forging, rolling, etc.).

MANDREL: A slight tapered, hardened steel shaft that supports work that cannot be held by any other method for machining between centers.

MARFORM: A drawing process that forms metal sheet by using a movable steel punch and a rubber headed ram.

MATH PLATE: Production type of pattern equipment usually made of metal. Consists of a plate on each side of which is mounted the matching halves of the pattern.

MESH: To engage gears to a working contact.

MILL: To remove metal with a rotating cutter on a milling machine.

MILLING MACHINE: A machine that removes metals from the work by means of a rotary cutter.

MINOR DIAMETER: The smallest diameter of a screw thread measured across the roots and perpendicular to the axis. Also known as the “root diameter.”

MITER GEARS: Right angle bevel gears having the same number of teeth. Used to transmit power through shafts at right angles to each other.

MORSE TAPER: A standard taper of approximately 5/8 in. per foot. Used on lathe centers, drill shanks, etc.

MUSIC WIRE: A carbon steel wire used to manufacture springs.

NC: Abbreviation for the National Coarse series of screw threads.

NECKING: Machining a groove around a cylindrical shaft.

NF: Abbreviation for the National Fine series of screw threads.

NITRIDING: A case hardening technique in which a ferrous alloy is heated in an atmosphere of ammonia or in contact with a nitrogenous material to produce surface hardness by the absorption of nitrogen. Quenching is not necessary.

NONFERROUS: Metal containing no iron.

NORMALIZING: A process in which ferrous alloys are heated to approximately 100 deg. F. above the critical temperature range and cooled slowly in still air at room temperature to relieve stresses that may have developed during machining, welding or forming operations.

NUMERICAL CONTROL SYSTEM: A system in which actions are controlled by the direct insertion of NUMERICAL DATA at some point. The system must automatically interpret this data.

NUMERICAL DATA: Data in which information is expressed by a set of number or symbols.

OBTUSE ANGLE: An angle of more than 90 deg.

OD: Abbreviation for outside diameter.

OFF – CENTER: Eccentric, not accurate.

OIL HARDENING: Using a mineral oil as a quenching medium in the heat treatment of certain alloys.

OPEN LOOP SYSTEM : A control system that has no means for comparing the output with the input for control purposes.

OUT- OF – TRUE: Not on center, eccentric, out of alignment.

PENNING: An operation that involves the mechanical working of metal by means of hammer-like blows.

PERMANENT MOLD: A mold ordinarily made of metal that is used for the repeated production of similar casting.

PICKLING: A technique employed in the removal of stains and oxide scales from metal surfaces by impression in acid baths.

PINION: The smaller of two mating gears.

PITCH: The distance from a point on one thread to a corresponding point on one thread to a corresponding point on the next thread.

PITCH DIAMETER: The diameter of an imaginary cylinder that would pass through the threads at such points as to make the width of the thread and width of the space equal at the point where they are cut by the cylinder. It is equal to the major diameter of the thread minus the depth of one thread. In gearing – the diameter of the pitch circle which is an imaging circle located at about midpoint on the teeth, where the teeth of both gears contact each other.

PLASTER MOLD CASTING: A casting process which uses plaster molds in place of sand molds. The castings produced in a plaster mold have a much better surface finish than those cast in sand. Used primarily with aluminum.