8
DIVIDERS – These are essentially scribers for marking arcs, and circles, hence their points are hard and sharp. They are used for dividing distances into a number of equal parts. Also used for transferring dimensions from a rule to the work.
DRILL GAUGE – Tool for measuring the size of drills.
DRILL GRINDING GAUGE – A tool for checking the angle and length of the cutting lips on a twist drill while grinding it. Also it may be called a drill point gauge or a drill angle gauge.
ENGINEERS TAPERS – are intended for measuring hole sizes, slot widths, caliper settings and so on.
FEELER GAUGES – Consist of a number of thin metal blades, each of a different thickness and in the desired number of dimensional steps.
They are used for checking clearances.
FIRTHS HARDOMETER – Instrument for measuring the hardness of materials, particularly metals.
GAUGE – A tool or instrument for checking or measuring the sizes of metal parts to determine whether the dimensions are within the specified limits.
GAUGE BLOCKS – are used mostly for reference in setting gauges and for accurate measurement in tool, gauge, and die manufacture.
HEIGHT GAUGE – Marking out or measuring tool designed on the lines of a scribing block, but capable of more accurate duty.
HERMOPHRODITE CALIPER – A caliper having one leg similar to that of an inside caliper, while the other leg is pointed like a divider leg.
HOOK RULE – A steel rule with a projecting piece or hook at one end at right angles to the edge of the rule.
INDICATING INSTRUMENTS – The instruments that provide visual observation of readings, such as pressure gauges, draft gauges, fuel oil meters and thermometers for fuel, feed water and flue gas temperatures etc.
INDICATOR – A sensitive instrument which shows slight variations when testing the trueness, or alignment of a workpiece, fixture or machine part such as a milling vice. Dial indicators may be graduated to read small linear variations.
Instruments and Gauges 111
INSIDE VERNIER CALIPER – is intended mainly for checking internal dimensions, such as the diameter of bores, and so on. Vernier protractor is used for measuring angles accurately.
JO BLOCKS – These refer to Johansson precision gauge blocks.
KNIFE EDGE VERNIER CALIPER – has jaws which are reduced to a very narrow edge. These are useful for measuring in restricted places or on curved surfaces.
LEVEL, HYDROSTATIC – U tube device employed during the levelling and setting of work too long for the use of a spirit level.
LEVEL, SPIRIT – Instrument consisting essentially of a small sealed glass tube containing spirit (alcohol or ether) so mounted that the enclosed bubble of air occupies a central position only when the instrument is placed horizontally.
LIMIT GAUGE – A gauge that represents a limiting (maximum and minimum) size within which the work will be acceptable.
MICROMETER – A precision, screw adjusted measuring instrument with which dimensions can be read in thousandths and ten thousandths of an inch.
MICROMETER COLLAR – A dial on the screw of a machine to indicate the extent of the movement of the screw or parts attached to the screw and usually graduated to read thousandths of an inch.
MICROMETER DEPTH GAUGE – The ordinary depth gauge has been elaborated by the addition of a micrometer head.
MINNIMETER – Delicate form of indicator showing the movement of a projecting plunger usually placed at one end.
ODD LEG – Caliper having one leg bent inwards at its ends, like the two legs on a pair of inside calipers, the other leg being pointed or having a separate hardened point attached to it.
OPTICAL FLAT – Plate generally made of glass or quartz and used as a standard of reference as a flat surface.
OPTICAL PROTRACTOR – Angle measuring instrument fitted with a scale read by an optical magnifying device.
PARALLEL BLOCK – Steel or cast iron block used when setting up work for machining, marking out or measuring.
PIN GAUGES – End measuring pins for determining bore diameters.
PLUG GAUGE – A gauge on which the outside measuring surfaces are designed to test the specified dimensions of holes. May be straight or tapered, plain or threaded, and of any cross-sectional shape.
PLUMB BOB – Weight hung on the end of a cord so that when the latter is supported at its top end the cord will hang vertical.
PNEUMATIC MICROMETER – An instrument designed to measure, among other things, the errors in the size, shape and alignment of bores, with compressed air.
PROTRACTOR – Instrument graduated so as to enable the measurement of angles to be made in degrees.
PYROMETER – Specified type of thermometer used to measure high temperatures in the production and heat treatment of metals and alloys.
RADIUS GAUGE – Tool used for checking the radius of small fillets or rounded corners.
RECORDING INSTRUMENTS – Instruments which provide a permanent record of readings such as steam pressure, steam flow, air flow, flue gas temperature, feed water temperature, fuel flow and fuel temperature.
RING GAUGE – A gauge in which the inside measuring surfaces are circular in form. A ring gauge may be cylindrical or conical, plain or threaded.
SCLEROSCOPE – Instrument for measuring hardness.
SCREW GAUGE – Type of gauge for checking the accuracy of a screw thread.
SCREW PITCH GAUGE – A small tool with a number of blades, each having the same number of notches per inch as the thread it represents. It is used to find the pitch and number of threads per inch on a screw, tap or die.
SCREW THREAD MICROMETER – Type of micrometer with measuring points specially shaped to enable the measurement of pitch diameter and thickness of thread.
SCRIBER – Used for making lines on the work when marking off.
SINE BAR – Tool used for the accurate setting out of angles by arranging to convert angular measurements to linear ones.
SLIP GAUGE – Form of gauge made of hardened steel with two parallel faces worked to high precision and at a known distance apart.
Instruments and Gauges 113
SNAP GAUGE – A type of fixed gauge, plain or adjustable, arranged with inside measuring surfaces for checking diameters, lengths, thicknesses or widths of workpieces.
SPRING CALIPERS – Inside or outside calipers for measuring workpieces in which the tension against the nut is maintained by a circular spring at the end.
STEEL RULE – A thin flat measuring tool graduated in either fractional or decimal part of an inch or cm and made in many styles and lengths.
STRAIGHT EDGE – Strip of metal, usually steel, with one edge straight, used to determine the flatness of a surface.
SURFACE GAUGE – Tool used for marking out and setting up work in conjunction with a surface plate, used also for levelling workpieces when fixing them to the worktables of machine tools e.g., planers, shapers, millers etc.
TAPER PLUG GAUGE – A solid internal gauge in the form of a frustrum of a cone having diameter, taper and length suitable for measuring the dimensions of an internal taper of specified size.
TAPER RING GAUGE – An external gauge, the internal diameter of which confirms to the frustrum of a cone having diameter, taper and length suitable for measuring the dimensions of an external taper of specified size.
TEMPLATE – A flat pattern or guide plate usually made from sheet metal and used as a gauge or guide when laying out, drilling, forming in a machine or filing irregular shapes on metal workpieces.
TELESCOPING GAUGES – Adjustable gauges which consists of a handle attached to a fixed contact within which a plunger contact expands or telescopes under spring tension when the gauge is inserted into the hole that is to be measured.
THREAD GAUGE – Tool for checking the form and pitch of screw threads.
TOOL MAKERS MICROSCOPE – Instrument used in accurate inspection of thread forms, form tools and complex contours.
TORQUE METER – Torsion measuring device fitted to a rotating shaft or component to measure the torque developed at any given moment under actual running conditions.
TORSIOGRAPH – Instrument used to measure and record the amplitude and frequency of torsional vibrations in a rotating shaft or other part.
TRAMMELS – are generally used for laying off and checking dimensions of several feet, they are generally used in conjunction with a large steel rule, which may be from 3 to 10 ft long.
TRANSFER CALIPER – A caliper designed to take measurement in recesses or over a projection. One leg can be separated or opened to remove the caliper and then returned to the measured size.
TRY SQUARE – Instrument used for setting and checking a line, an edge or a face which is required to be at right angles to some other plane which should be regarded as a datum or reference plane.
VACUUM GAUGE – Gauge used to measure the amount of vacuum in any vessel in which a pressure lower than atmospheric pressure is produced by evacuation of air, vapour and gas.
VERNIER – Small-scale, for making accurate measurement, carrying a certain number of graduations equalling in their combined length a different number of graduations, usually one more or one less, on the main scale of the instrument to which the vernier is attached.
VERNIER CALIPER – Precision measuring instrument consisting of a beam or rule having a fixed jaw at one end, and a straight jaw to which is attached a vernier scale.
WATER GAUGE – A gauge that shows the proper water level which must be maintained in a boiler to avoid overheating damage.
WIRE GAUGE – Sizes of standard wire and sheet metal are normally expressed not by a dimension in cm, but by a number or gauge size.
WHITWORTH GAUGE – Type of plug, and caliper gauge introduced by Joseph Whitworth.
WICKMAN GAUGE – Special form of adjustable snap or horse shoe type of gap gauge.
AERATOR – A device for fluffing (or decreasing the density of ) and cooling the sand by the admixture of air.
AIR GATE – A vertical channel for the removal of gases from the mould;
checking of the filling of the mould cavity with metal and feeding up the casting with metal during solidification.
AIR HOLE – Hole in a casting caused by air or gas trapped in the metal during solidification.
AIRLESS BLAST CLEANING – A process whereby the abrasive material is applied to the object being cleaned by centrifugal force generated by a rotating vane type wheel.
ANTIPIPING (material) – Usually refers to an insulating material placed on the top of a sprue or riser that keeps the metal in liquid or semiliquid form for a long period of time and minimizes the formation of the usual conical pipe or shrink in the top of a sprue or riser.
ARBOR – A metal barrel, frame, or plate to support or carry part of a mould or core.
ATMOSPHERIC RISER – Blind riser which employs atmospheric pressure to aid feeding.
BACK DRAFT – Taper or draft which prevents removal of pattern from the mould.
BACKING SAND – Sand between the facing sand and the flask.
BAKED CORE – The core which has been subjected to heating or baking until it is thoroughly dry, as opposed to green sand core which is used in the moist state.
9
CHAPTER CHAPTER
CASTING
9
BASIN – A cavity on top of the cope into which molten metal is poured before it enters the sprue.
BEDDED IN MOULD – is the mould, the bottom half of which is made in the sand in the floor of the foundry. It may be covered with a cope, or cast open, according to the type of work.
BINDER – Material used to hold the grains of sand together in moulds or cores. May be cereal, oil, clay, resin, pitch etc.
BINDER, PLASTIC (resin) – Synthetic resin material used to hold grains of sand together in moulds or cores, may be phenol formaldehyde or urea formaldehyde thermosetting types.
BLACKING – Carbonaceous material for coating mould or core surfaces.
BLACK LEAD – Graphite for facing moulds and cores.
BLAST CLEANING – Removal of sand or oxide scale from castings by the impinging action of sand, metal shot or grit projected under air, water or centrifugal pressure.
BLEED – Molten metal oozing out of a casting stripped or removed from the mould before solidification.
BLENDED SAND – Mixture of sands of different grain sizes, clay content etc. to produce one, possessing characteristics more suitable for foundry use.
BLIND RISER – An internal riser which does not reach to the exterior of the mould.
BLISTER – Defect on the surface of a casting appearing as a shallow blow with a thin film of metal over it.
BLOWN CASTINGS – Castings in which bubbles, or blowholes, have been caused through gases, steam etc., generated when the mould is cast, finding their way into the metal.
BOND CLAY – Any clay suitable for use as a bonding material in the moulding sand.
BORIC ACID – Inhibitor used in facing sand for magnesium base and aluminium base alloys high in magnesium to prevent reaction with moisture in the sand.
BORON TRICHLORIDE – A product used for degasification of aluminium alloys.
Casting 117
BOSSES – Bosses are often located on a wall of a casting and should be so designed that a heavy section of metal leads to the riser.
BOT – Clay wedge used in a cupola to stop the hole through which the metal is run.
BUCKLE – Defect in a casting surface appearing as an indentation resulting from an expansion scab.
BURN ON – Adhesion of sand to the casting, usually due to the metal penetrating into the sand.
BURN OUT – Usually refers to the removal of the disposable wax or plastic pattern in the investment moulding process by heating the mould gradually to a sufficiently high temperature to consume any carbonaceous residues.
BUTT RAMMAR – The flat end of the molders rammer.
CALCIUM BORIDE – An alloy of calcium and boron corresponding (when pure) to the formula CaB6 containing about 61% boron and 39%
calcium, and used in deoxidation and degasification of nonferrous metals and alloys.
CALCIUM MANGANESE SILICON – An alloy containing 17 to 19%
calcium, 8 to 10% manganese, 55 to 60% silicon and 10 to 14% iron used as a scavenger for oxides, gases and nonmetallic impurities in steel.
CALCIUM SILICON – An alloy of calcium, silicon and iron containing 28 to 30% calcium, 60-65% silicon and 6% max iron, used as a deoxidizer and degasifier for steel and cast iron.
CASTING – Metal poured into a mould to form an object. Act of pouring molten metal into a mould.
CASTING STRAINS – Strains resulting from internal stresses created during cooling of a casting.
CAVITY, MOULD or DIE – Impression or impressions in a mould or die that give the casting its shape.
CENTRIFUGAL CASTING – Process of filling moulds by pouring the metal into a sand or metal mould revolving about either its horizontal or vertical axis and continue pouring the metal into the mould that is being revolved before solidification of metal is complete. Molten metal is moved from the center to the periphery by centrifugal action.
CERAMIC MOULD – Mould in which the refractory and binder are such that when fired at high temperature, a rigid structure is formed. The mould can be made in a flask or in the form of a shell.
CEREAL – Substance derived from corn flour, which is added to core and moulding sands to improve their properties for casting production.
CHALK TEST – Method of crack detection which consists of applying a penetrating liquid to the excess from the surface which is then coated with whiting or chalk. After a short time, the penetrant seeps out of the cracks into the whiting, causing an appreciable difference in whiteness.
CHAMOTTE – Coarsely graded refractory material prepared from calcined clay and ground firebrick mulled with raw clay, used in steel foundries.
CHAPLET – A metallic insert or support to hold the core in position in the mould.
CHEEK – Intermediate sections of a flask inserted between cope and drag.
CHILL – A metal object placed on the outside or inside a mould cavity to induce more rapid cooling at that point and thereby produce hard zone i.e., hard, unmachinable surface.
CHILL TEST – Method of determining the suitability of a gray iron for specific castings through its chilling tendency, as measured from the tip of a wedge shaped test bar.
CHILLED IRON – Cast iron poured against a chill to produce a hard unmachinable surface.
CHOKE – Restriction in a gating system to control the flow of metal beyond that point.
CHVORINOV’S RULE – Solidification time is proportional to the square of the volume of the metal and inversely proportional to the square of the surface area.
CLEANING – Process of removing sand, surface blemishes etc. from the exterior and interior surfaces of a casting. Includes degating, tumbling, or abrasive blasting, grinding off gate stubs.
COD – A sand projection left behind in the mould by some patterns. Strictly speaking it is a core.
COLD SHUT – Where two streams of metal do not unite thoroughly in a casting.
Casting 119
COMBINATION DIE – A die casting die having two or more cavities of dissimilar parts.
CONTRACTION – Act or process of a casting becoming smaller in volume and/or dimensions during the solidification of the metal or alloy which composes the casting.
COPE – The upper or top most section of a flask, mould or pattern.
COPE (false) – A temporary cope which is used only to establish the parting line.
CORE – Separable part of the mould, usually made of sand and generally baked, to create openings and various shaped cavities in the castings.
Also used to designate the interior portion of an iron base alloy which after case hardening is substantially softer than the surface layer or case.
CORE BINDER – Any material used to hold the grains of core sand together.
CORE BOX – Box with an opening in which the core is formed.
CORE PRINT – An extension of the pattern for locating the core or an extension of the mould cavity for locating the core.
CORE (ram up) – Core attached to the pattern and rammed up in the mould, where it remains when the pattern is withdrawn.
CORE SHIFT – Defect resulting from movement of the core from its proper position in the mould cavity.
CORE VENTS – A wax product, round or oval in form, used to form the vent passage in the core.
CRUSH – Casting defect appearing as an indentation in the surface due to displacement of sand in the mould, usually at the joint surfaces.
CUTS – Defects in castings resulting from erosion of the sand by the molten metal pouring over the mould or core surface.
DEGASSIFIER – A material employed for removing gases from metals and alloys.
DEOXIDIZER – A material used to remove oxygen or oxides from metals and alloys.
DESULPHURIZER – A material used to remove sulphur from molten metals and alloys.
DIE CASTING – Pouring molten metal under pressure into metal moulds.
DIRECTIONAL SOLIDIFICATION – It refers to the solidification which proceeds along a cast member in the direction of the hotter metal.
DIRT – Any extraneous material entering a mould cavity and usually forming a blemish on the casting surface.
DRAFT – Taper allowed on the vertical faces of a pattern to permit removal of it from the sand mould without excessive rapping or tearing of the mould walls.
DRAG – The lower or bottom section of a mould or pattern.
DRY SAND MOULD – A mould made of prepared moulding sand dried thoroughly before being filled with metal.
EROSION SCAB – Casting defect occurring where the metal has been
EROSION SCAB – Casting defect occurring where the metal has been