Cnc glossary 4

anandengg's version from 2018-03-23 08:47


Question Answer
Idler – A gear or gears placed between two other gears to transfer motion from one gear to the other gear without changing their speed or ratio.
Independent Chuck – A chuck in which each jaw may be moved independently of the others.
Indexing– The process of positioning a workpiece for machining it into equal spaces. dimensions. or angles using an. index or dividing head.
Indexing Fixture– A complete indexing unit composed of a dividing head and rootstock. (See dividing head.)
Index Plate– A metal disk or plate punched with many holes arranged in a series of rings. one outside the other each ring containing a different number of holes.
Indicator – A precision instrument which shows variations of thousandths of an inch or less when testing the trueness or alignment of a workpiece, fixture, or machine.
Inserted-Tooth cutter– A milling cutter designed with replaceable cutting tooth inserts to save the expense of a new cutter whenever the teeth become damaged or worn. Generally, they are made 6 inches or more in diameter.
Intermediate Gear– See idler
Jack, Leveling– Small jacks (usually screw jacks) for leveling and holding work on planner beds and similar places.
Jacobs Chuck– Common term for the drill chuck used in either the headstock spindle or in the tailstock for holding straight-shank drills, taps, reamers, or small diameter workpieces.
Jarno– A standard taper having 0.600-inch taper per foot used on some machine tools.
Jig– A production work holding device that locates the workpiece and guides the cutting tool (see fixture).
Johannson Blocks (Jo blocks)– Common term for the precision gage blocks used and accepted as dimensional standards by machinists, toolmakers. and inspectors.


Question Answer
Kerf– The width of cut made by a Saw.
Key– One of the several types of small metal objects designed to fit mating slots in a shaft and the hub of a gear or pulley to provide a positive drive between them: also. the name of the T-handle wrench used on chucks.
Key Seat– A recessed groove (slot) machined into a shaft or a part going on the shaft (usually a wheel or gear).
Knee– That part of a column of a knee-type milling machine which carries the saddle and the table and provides the machine with vertical feed adjustments. Also, the name of a precision angle plate called a “toolmaker’s knee”.
Knurl– A decorative gripping surface of straight-line or diagonal design made by uniformly serrated rolls called knurls.
Knurling– The process of finishing a part by scoring (pressing) patterns on the surface of the work.


Question Answer
Land– That surface on the periphery of a rotary cutting tool, such as a milling cutter. drill tap, or reamer, which joins the face of the flute or tooth to make up the basic cutting edge.
Lap– A tool made of soft metal and charged With fine abrasives for precision finishing of metal surfaces. Also, to perform the operation using a lap
Lard Oil– A cutting oil made from animal fats usually mixed with mineral oils to reduce its cost and improve its qualities.
Layout– To locate and scribe on blank stock the shape and size dimensions required to machine or form the part.
Lead– The distance a thread will advance along its axis in one complete revolution. Also, a heavy, soft’, malleable metal having a low melting point. It has a bright. silvery color when freshly cut or poured and turns to a dull gray with aging.
Lead Screw– The long, precision screw located in front of the lathe bed geared to the spindle, and used for cutting threads. Also, the table screw on the universal milling machine when geared to the indexing head for helical milling.
limits– The smallest and largest dimension which are tolerable (allowed).
Lip of a Drill– The sharp cutting edge on the end of a twist drill.
Loading– A condition caused by grinding the wrong material with a grinding wheel or using too heavy a grinding action.


Question Answer
Machinability– The degree of difficulty with which a metal may be machined; may be found in appropriate handbooks.
Machine Tool– A power-driven machine designed to bore, cut, drill, or grind metal or other materials.
Machining, Finish– Machining a surface to give it the desired finish.
Machinist– A person who is skilled in the operation of machine tools. He must be able to plan his own procedures and have a knowledge of heat-treating principles.
Machining, rough (rough finishing)– Removing excess stock (material) with a machine tool thus shaping it in preparation for finish machining.
Magnesium– A lightweight, ductile metal similar to but lighter than aluminum.
Magnetic Chuck– A flat’. smooth-surfaced work holding device which operates by magnetism to hold ferrous metal workpieces for grinding.
Malleable– Capable of being extended or shaped by hammering or rolling.
Mandrel– A precision-made tapered shaft to support work for machining between centers.
Mesh– To engage. as the teeth between two gears.
Mic; Mike– A term used for micrometer, or to measure with a micrometer.
Micrometer,Depth– A micrometer in which the spindle projects through a flat, accurately machined bar.. used to measure the depth of holes or recesses.
Micrometer, Thread – A micrometer in which the spindle is ground to a point having a conical angle of 60 degrees. The anvil, instead of being flat. has a 60 degree V-Shaped groove which fits the thread.
Mild Steel– A term used for low-carbon machine steel.
Mill– A milling machine; also, the act of performing an operation on the milling machine.
Milling, Climb– See climb milling. milling, face-See face milling.
Milling Cuffer– A cutting tool, generally cylindrical in shape. used on a milling machine and operated essentially like a circular saw.
Minor Diameter – The smallest diameter of a screw thread. Also known as the “root diameter.”
Morse taper– A self-holding standard taper largely used on small cutting tools such as drills, end mills, and reamers, and, on some machines, spindles in which these tools are used.
Multiple-Thread Screw– A screw made of two or more threads to provide an increased lead with a specified pitch.
Music Wire– A high-quality steel wire used for making springs. Also called piano wire.
Necking– Machining a groove or undercut in a shaft to permit mating parts to be screwed tightly against a shoulder or to provide clearance for the edge of a grinding wheel.
Nickel– An alloying element which increases the strength, toughness, and wear and corrosion resistance of steels.
Nitrating– A case hardening process in which ammonia or some other form of nitrogen is introduced to the surface of certain alloys.
Nonferrous– Metal containing no iron, such as brass and aluminum.
Normalizing– Process of heating a ferrous metal or alloy to above its critical temperature and cooling in still air to room temperature to relieve Internal stresses.
Off Center –Not centered; offset, eccentric, or inaccurate.
oil hardening– The process of quenching in oil when heat treating alloy steel to bring out certain qualities.
Oilstones –Molded abrasives in various shapes used to hand-sharpen cutting tools.
Overarm – The support for the end of a milling cutter which is on the opposite side of the cutter from the spindle and column.


Question Answer
Pack Hardening– A heat-treating process in which the workpiece is packed into a metal box together with charcoal, charred leather. or other carbonaceous material to case-harden the part.
Parallels– Hardened steel bars accurately ground to size and ordinarily made in pairs in many different sizes to support work in precision setups.
Parting –The operation of cutting off a piece from a part held in the chuck of a lathe.
Pawl– A pivoted lever or sliding bolt that secures as an automatic directional table control on a grinder.
Peen– To draw, bend. or flatten, also, the formed side of a hammer opposite the face.
Pilot– A guide at the end of a counterbore which keeps it aligned with the hole.
Pilot Hole– A starting hole for large drills to serve as a guide, reduce the resistance, and aid in maintaining the accuracy of the larger hole. Also called a lead hole.
Pinning– A term used to describe the condition of a file clogged with metal filings causing it to scratch the work.
Pitch– The distance from any point on a thread to the corresponding point on the adjacent thread. measured parallel to the axis. Also applied to spur gears-. see diametral pitch.
Pitch Circle– The line (circle) of contact between two meshing gears.
Pitch Diameter– The diameter of a thread at an imaginary point where the width of the groove and the with of the thread are equal.
Pitch Line– An imaginary line which passes through threads at such points that the length of the part of the line between adjacent threads is equal to the length of the line within a thread.
Plain Cutter– A milling cutter with cutting teeth on the periphery (circumference) only.
Play– The looseness of fit (slack) between two pieces press fit-See force fit.
Punch, Prick– A solid punch with a sharp point, used to mark centers or other locations on metal.
Pyrometer– A device for measuring the high temperatures in a heat-treating furnace.


Question Answer
Quench– To rapidly cool heated metal in water, oil brine, or air in the process of heat treating.
Quick Return– A mechanism on some machine tools that provides rapid movement of the ram or table on the return or anointing stroke of the machine.
Rack– An array of gears spaced on a straight bar.
Radial– In a direction directly outward from the center of a circle or sphere or from the axis of a cylinder. The spokes of a wheel, for example, are radial.
Radius – The distance from the center of a circle to its circumference (outside).
Rake– That surface of a cutting tool against which the chips bear while being severed. If this surface is less than 90″ from the surface being cut, the rake is positive-, if more, the rake is negative.
Ram – That part of a shaper which moves back and forth and carries the tool head assembly.
Rapid Traverse– A lever-controlled, power-operated feature of some machines that permits the rapid movement of the worktable from one position to another.
Reaming, Line– The process of reaming two or more holes to bring them into very accurate alignment.
Recalescence– An increase of temperature that occurs while cooling metal through a range of temperatures in which changes in metal occur.
Recess– An internal groove. See undercut.
Relief– A term for clearance or clearance angle.
Roughing– The fast removal of stock to reduce a workpiece to approximate dimensions’. leaving only enough material to finish the part to specifications.
Rule, Hook– A rule with a hook on the end for measuring through pulley holes and in similar places.
Running Fit– A class of fit intended for use on machinery with moderate speeds, where accurate location and minimum play are desired.