DICTIONARY OF AUTOMOTIVE TERMS-"Bu"

Bubble
  1. A small blister in the finish of paint.
  2. The bubble of air and spirit vapor within a Level tube loosely, the level tube itself.
Bubble car
A type of small car which was popular in the 1950s. It had a bulbous-shaped glass front to provide maximum interior room in spite of its small size. The door opened to the front of the driver. Examples are the BMW Isetta and Heinkel Trojan.
Bubble film
Duplex polymer film with regular array of bubbles thermoformed into one side, used for crush-proof packaging.
Bubble pack
See
Bubble stabilization
Tendency of polymer bubble blown after extrusion in manufacture of film to maintain a constant shape without breaking or collapsing. Depends on tension stiffening behavior of molten polymer.
Bubble Wrap
Sheet of plastic with a series of small air bubbles used as packing material.
Bucciali
A vehicle brand of which the TAV 8, TAV 30, TAV 12 and Double Huit models with required application are classic cars.
Buchholz relay
A protective relay for use with transformers or other oil-immersed apparatus; it embodies a float which becomes displaced and operates the relay contacts if gas bubbles are generated by a fault within the equipment being protected.
Buchmann-Meyer effect
The special type of reflection of light from the sound-track on a disk record whereby the lateral velocity of the track can be determined.
Buck
In the design process of creating a vehicle, a buck is an accurate representation of only the vehicle's interior which includes the seats, pedals, instruments, steering wheel, doors, and floor in order to evaluate style, ergonomics, comfort, function, etc.
Also see
Bucket
See
Bucket conveyor
A conveyor or elevator consisting of a pair of endless chains running over toothed wheels, and carrying a series of buckets which, on turning over, discharge their contents at the delivery end.
Bucket seat
Bucket Seat

Bucket Seat

An individual seat which is found in pairs in the front of a vehicle. Named because the curvature of the backrest and cushion resembles a cut-out bucket.
Bucket tappet
Bucket tappet

Bucket Tappet

Valve lifters that are hollow, cylindrical, and closed at one end and used with some overhead camshafts. The flat, closed end of the tappet (bottom of the bucket) rests against the Camshaft lobe with part of the Valve spring and Valve stem enclosed by the Cylinder. Called bucket tappets because they are shaped like upside-down buckets.
Bucket valve
A non-return (delivery) valve fitted in the bucket or piston of some types of reciprocating pump
Bucket coil
A winding on an electromagnet to oppose the magnetic field of the main winding. Such a device is sometimes used in electromagnetic loudspeakers to smooth out voltage pulsations in the power supply. Also called hum-bucking coil.
Buckland
See
Buckle
  1. A locking clasp usually found on seat belts and tie-down straps.
  2. A metal strap
  3. In foundry work, a swelling on the surface of a sand mold due to steam generated below the surface.
  4. To crumple up, especially when metal bends in a vehicle accident. To twist or bend out of shape such as when plates of metal or a structural member deforms under compressive load.
Buckled plates
Battery plates that have been bent or warped out of a flat plane.
Buckler
A portable cover secured over the deck opening of the hawsepipes and the chain pipes to restrict the flow of water through the openings.
Buckle up
To put your seat belt on. British term is belt up
Buckley gauge
A sensitive ionization gauge for measuring very low gas pressures.
Buckling
  1. A distortion of accumulator plates caused by uneven expansion, usually as a result of heavy discharges or other maltreatment.
  2. Mode of deformation in which an elastic instability occurs in a plate or a structural member under compressive load, resulting in a twisting or bending out of shape. Usually leads to plastic deformation and eventual collapse.
  3. A term in reactor diffusion theory giving a measure of curvature of the deutron density distribution. The geometric buckling depends only on the shape and dimensions of the assembly while the material buckling provides a measure of the multiplying properties of an assembly as a function of the materials and their disposition.
Buck transformer
Transformer with secondary in mains circuit to regulate voltage according to a controlling circuit feeding the primary. Also called boost transformer
BUDC
Acronym for Before upper dead center". Same as BTDC.
Budd mounting
See
Budd wheel
A ten-hole, stud-piloted disc truck wheel originally designed by the Budd Corporation.
Buff
  1. To Polish.
  2. A revolving disk composed of layers of cloth charged with abrasive powder; used for polishing metals.
  3. An expert in a field or a person greatly interested in the field as in Jim is a car buff.
    Also see
Buff contour
The specked shape of a buffed retread tire.
Buffed crumb
Flakes of rubber produced by abrading treads of worn tires for retreading; of limited use as recycled material for new tire compounds.
Buffer
  1. A machine used to Rasp the old tread from the tire.
  2. An electronic amplifier, often with unity gain, which is designed to decouple input from output. Normally designed to have high input impedance so that it does not load the driving stage and low output impedance such that it can provide current drive.
  3. A spring-loaded pad attached to the framework of railway rolling-stock to minimize the shock of collision; any resilient pad used for a resilient purpose. May be hydraulically controlled or dampened.
  4. A substance added to an electrolyte solution which prevents rapid changes in the concentration of a given ion. Also called buffer reagent
Also see
Buffer battery
A battery of accumulators arranged in parallel with a DC generator to equalize the load on the generator by supplying current at heavy-load periods and taking a charge during light-load periods
Buffer capacitor
See
Buffer circuit
The resistance-capacitor unit which determines the rate of rise or fall of the envelope of the waveform of emitted sounds which has been generated in electrostatic circuits in electronic organs.
Buffered radius
A dimension that ensures the proper contour of the buffed surface according to tire size and type and matrix dimensions.
Buffer reagent
A substance added to an electrolyte solution which prevents rapid changes in the concentration of a given ion. Also called buffer.
Buffer spring
The part lending resiliency to railway buffing gear.
Also see
Buffer tank
A closed tank that cushions the explosive expulsion of liquid from a system connected to it by controlling the gas pressure in the tank.
Buffet boundary
The limiting values of the speed of sound and altitude at which an aircraft can be flown without experiencing buffet in unaccelerated flight.
Buffeting
  1. Severe, pulsating force of wind. When you drive in a convertible with the top down, you will often experience this buffeting action of the wind. It is also noticeable when a vehicle is driven quickly with the windows down.
  2. An irregular oscillation of any part of an aircraft, caused and maintained by an eddying wake from some other part; commonly, tail buffeting in the downwash of the main plane, which gives warning of the approach of the Stall.
Buffing
  1. Smoothing and polishing a surface by using a Buffing wheel and polishing paste or liquid.
  2. Grinding or Rasping off remaining tread rubber to give the Casing proper texture to accept new retread stock and proper dimensions to fit the matrix.
Buffing template
A machined device of a specific shape used to obtain the required Buffed contour.
Buffing wheel
A disc which is covered in soft cloth or lambswool. It is powered by a tool like a drill which spins the disc to give a high gloss shine to the surface of a vehicle.
Buff line
The dividing line in the cross section of a tire between the buffed surface of the original tire and the new retread rubber.
BUG
Acronym for Bicycle user group or bus user group to represent cyclists or bus travelers.
Bug and tar remover
A solution which will dissolve bugs and tar residue. After application, it needs to be washed off or it will also remove the paint.
Bugatti
Bugatti

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Bugatti

A vehicle brand of which all pre-1948 models (except types 52 and 68) are classic cars. The 1951 Type 101 model is a milestone car.
Bug deflector
Honda Accord

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Bug Deflector

A length of clear plastic which is attached to the front of the hood to prevent bugs from hitting the Windshield. Also called a bug shield.
Bug out
Trucker slang for leaving a CB radio channel as in "I better bug out and get some shut eye."
Bug shield
See
Buick
Buick

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Buick

A vehicle manufacturer which began in 1906 and is now part of General Motors . The 1931-32 series 90 and Limited with required application are classic cars. The Riviera for 1949 and 1963-70 are milestone cars. The 1953-54 Skylark are also milestone cars. Models include the following:
Build
  1. A change from the standard process assembly of a vehicle specified by the VIN
  2. The thickness of the paint film deposited on the body during spraying (measured in mils).
Also see
Build date code
A code which tells you what day, month, and year the engine was made. Expressed alpha-numerically and stamped somewhere on the block.
Builder
In retreading a tire, a machine used to apply tread rubber to a Casing.
Also see
Builders and Repairers Association
See
Building basin
A structure in which one or more ships may be built and floated by flooding the basin.
Building Materials cargo
Truck cargo containing bricks, blocks, cement in bags, insulation, drywall, paint, hardware, etc.
Building Slip
A place where a ship is built
Also see
Build outs
Curbs which extend from the side of the road into the lane to reduce traffic speed.
Build quality
The quality of workmanship and material composition in the construction of a vehicle.
Build up
  1. To increase the surface level of metal by welding more material on it (and later grinding it to shape) or by adding filler to it.
  2. To assemble or put something together.
  3. To add material to something.
Also see
Buildup
  1. The amount a weld face is extended above the surface of the metals being joined.
  2. An excess of some material as in, "There was a buildup of carbon on the top of the piston."
    Also see
Built-up crankshaft
A crankshaft which is not cast or forged as one piece, but made of several different parts.
Build-up sequence
The order in which successive welding runs or beads are applied in joining thick plates to achieve maximum strength with acceptable stress from heat distortion.
Bulb
  1. A round area for vehicle turnaround typically located at the end of a cul-de-sac street.
  2. An electronic device which gives off light by the heating of an element contained with a glass enclosure. The metal base which conducts the electricity may be a barrel with locating pins, or it may have small Filament wires protruding from the base. In some cases it is a tube with contacts at either end. When replacing bulbs, especially high intensity bulbs like halogen, be sure to avoid touching the glass. The oil from your fingers will cause the bulb to overheat and burn out quickly. If you do touch the glass, you need to clean it with alcohol and air dry it.
Also see
Bulb bar
A rolled, or extruded, bar of strip form in which the section is thickened along one edge.
Bulb blackening
The blackening of a light bulb; gradual blackening of conventional, i.e., non-halogen light bulbs, occurs as a result of metal vapor deposition on the glass envelope which reduces light emission; severe blackening indicates imminent bulb failure
Bulb holder
See
Bulb Hygrometer
See
Bulb Plate
A narrow plate which is reinforced on one long edge.
Bulb Temperature
See
Bulk
Also see
Bulk cargo
Loose and unpackaged goods such as oil, coal, ore, woodchips, etc. sometimes referred to as aggregate cargo.
Also see
Bulk carrier
A ship designed to carry unpackaged cargo such as grain, woodchips, ore, coal, etc.
Bulk charging
Using large containers of refrigerant to charge the system. Commonly employed with charging stations to perform complete system charges.
Bulk freight
Loose goods (like woodchips, grain, petroleum, ore, and coal) that are not packaged in a box, bottle, etc.
Bulkhead
  1. A structural partition that separates compartments. This is generally a metal wall that extends from one side of a vehicle to the other. In the engine compartment, you would find a radiator bulkhead near the front and a firewall bulhead near the back of the engine bay. Another bulkhead separates the passengers from the trunk. The dashpanel is also a bulkhead.
    Also see
  2. In a public service vehicle (i.e., taxi, limo), the partition which separates the driver from the passengers.
  3. Vertical partition walls which separates the interior of a ship into compartments or rooms.
  4. In an airplane fuselage, the major structural transverse dividing wall providing access between several internal sections, or a strengthened and sealed wall at the front and rear designed to withstand the differential pressure required for pressurization.
  5. In a power plant nacelle, the structure serving as a firewall.
  6. A masonry or timber partition to hold back soil found in a tunnel or along a waterfront.
  7. A wall-like structure used at the front of a flatbed or back of the power unit to protect against damage from shifting cargo, or a wall inside any trailer that partitions the load.
Also see
Bulkhead connector
An OEM device used to connect wiring inside the vehicle body with wiring outside the body. Usually located at the bulkhead or firewall.
Bulkhead deck
The uppermost deck to which the transverse watertight bulkheads are carried.
Bulking factor
Ratio between the volume of loosely placed material and the same weight of material when compacted to a given specification.
Bulk refrigerant drum
A large (e.g., 10 lbs, 25 lbs, 30 lbs) container of refrigerant generally used in professional air conditioning service shops which employ charging stations to perform complete system charges.
Bulk sales
Wholesale sales of gasoline in individual transactions which exceed the size of a truckload.
Bulk station
A facility used primarily for the storage and/or marketing of petroleum products, which has a total bulk storage capacity of less than 50,000 barrels and receives its petroleum products by tank car or truck.
Bulk Storage
  1. The storage of product in a shipping container
  2. The storage of loose, unpackaged product
Bulk terminal
A facility used primarily for the storage and/or marketing of petroleum products, which has a total bulk storage capacity of 50,000 barrels or more and/or receives petroleum products by tanker, barge, or pipeline.
Bulk test
Test for materials having a high attenuation for use as a radiation shield.
Bulk Trailer
A truck trailer that carries bulk cargo like woodchips, grain, petroleum, ore, and coal
Bulk Truck
A straight truck that carries bulk cargo like woodchips, grain, petroleum, ore, and coal
Bull bar
The upward extension of a bumper to protect lights and the grille.
Also see
Bulldog
Trucker slang for a Mack truck as in "Who we got in that eastbound bulldog."
Bulldozer
A power-operated machine, provided with a blade for spreading and leveling materials.
Also see
Bullet-point pick hammer
See
Bull-headed rail
A rail section once used widely in the UK, having the shape roughly of a short dumb-bell in outline, but with unequal heads, the larger being the upper part in use.
Bull horn
A warning horn that sounds like the bellow of a bull or the moo of a cow.
Bullhorn handlebar
bullhorn

Bullhorn bar

A bicycle handlebar that proceeds laterally through the center attaching bracket and then rises upward at each end.
Bullion
  1. Gold or silver in bulk, i.e., as produced at the refineries, not in the form of coin.
  2. The gold-silver alloy produced before the metals are separated.
Bullion content
In parcel of metal of minerals being sold, where the main value is that of the base metal which forms the bulk of the parcel, the contained gold or other precious metal of minor value included in the sale.
Bull low
The lowest gear in a Transmission. Some older transmissions listed their gears as bull low (used for getting out of a stuck condition or climbing a very steep hill), low or first (used for starting out from a stop or for climbing a moderate hill), second (used for town driving or slight hills), third (used for highway cruising).
Bullnose
The upright radiator shape of 1913-30 Morris Oxford and Morris Cowley cars and vans which resembled a bull's nose. Also called Flatnose or Snubnose
Bull-ring
A metal ring used in the construction of overhead contact wire systems for electric schemes; it forms the junction of three or more straining wires.
Bull Riveting
To drive in rivets with a high powered air or hydraulic machine.
Bultaco
Bultaco

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Bultaco

A motorcycle manufacturer
Bulwark
  1. Fore-and-aft vertical plating immediately above the upper edge of the sheer strake.
  2. A sea-wall built to withstand the force of the waves; in some cases the reinforcement of the natural Breakwater.
Bump
Bump

Bump Sign

  1. A slight rising of the pavement possibly caused by a frost heave and if severe enough will be indicated by a sign
  2. The upward movement of the wheels and Suspension. Also called Jounce.
  3. The action of a vehicle dealer who increases the sale price of the vehicle, interest rate, monthly payments, etc.
Also see

Bump and rebound
The two stages of suspension movement requiring damping.
Also see
Bumper
On early vehicles, a bumper was a separate metal bar or blade at each end of a vehicle to prevent damaging the main part of the vehicle from hitting an obstruction or being hit by another vehicle. In modern vehicles the bumpers are integrated with the body panels and is secured by hydraulic rams.
Also see
Bumper bar
A tubular bar or series of bars which are designed to protect the front of a vehicle.
Bumper blade
A flat bar which is designed to protect the front or rear of a vehicle.
Bumper bracket
A device to which the bumper is attached to the frame, body, or chassis.
Bumper filler
A small panel usually made of plastic which fits between the bumper and the body of the vehicle.
Bumper horn
A short bumper extension which is mounted vertically (i.e., perpendicular to the main bumper), usually one on each side of the bumper. The British term is overrider
Bumper insert
A rubber or plastic strip fitted to the width of a bumper to prevent scoring of the bumper.
Bumper iron
A Bumper bracket
Bumper jack
Bumper jack

Bumper jack

A device for lifting one corner of a vehicle to change a tire. Older cars used a long bar which fitted into a base. A device on the long bar had a hook which was placed in a strategic place on the vehicle. A Lug wrench was inserted into the other end of the device and used to move the moveable part up the long bar thus lifting the vehicle.
Bumper Pan
Sheetmetal below the bumper to keep dirt and debris from entering the engine bay. Also called "modesty panel" or "modesty skirt."
Bumper panels
See
Bumpers
See
Bumper skirt
See
Bumper Spring
See
Bumper sticker
  1. A piece of rectangular paper with a sticky back which can be attached to the back of a vehicle to promote something
  2. Trucker slang for a car following too closely as in "Hey Charlie better watch out you got a bumper sticker on your backdoor."
Bumper system
An energy-absorbing system with some type of deformable material including Hydraulic Cylinders which enable the bumpers to protect the vehicle from damage in low-speed impacts.
Bumper to bumper
  1. A traffic condition in which a line of vehicles are stopped one after the other or are moving very slowly.
  2. A way of expressing the entire vehicle from one bumper to the other.
Bumping
The action of correcting damaged panels by pounding out the dent.
Bumping blade
An autobody tool used for slapping out slight dents (sometimes without a supporting dolly). It has slight serrations which hold the metal to avoid stretching. Also called a bumping file.
Bumping file
An autobody tool used for slapping out slight dents (sometimes without a supporting dolly). It has slight serrations which hold the metal to avoid stretching. Also called a bumping blade.
Bumping hammer
An autobody hammer used with a dolly for restoring a panel's shape.
Also see
Bumping out
An autobody term in which a damaged panel is hit with a hammer until it is nearly the correct shape.
Bumping spoon
See
Bump rubber
See
Bump start
  1. A method of starting a manual transmission (not for automatics) vehicle by pushing it (especially down a hill) and letting in the clutch while in second gear and the ignition set to the on position.
  2. To start a car using a bump start.
Bump steer
When an uneven road surface causes a vehicle to steer or lose Directional stability, this is called bump steer. At the front, bump steer is associated with the tie-rod and linkage-arm relationship. It is caused by the method of locating the Rear suspension, the type of rear suspension, and the geometry of the various Linkages. In race cars, bump steer is designed out of the Suspension so that the handling is as precise as possible. In most cars it is present to some degree. In fact, it can be useful to allow engineers to design a small amount of Understeer or Oversteer into the Chassis.
Bump stop
Bump stop

Bump stop

A cushioning device, usually rubber, that limits the upward movement of the wheels and Suspension to prevent metal-to-metal contact that could lead to Suspension damage or failure. Also called Jounce bumpers.
Bunched conductors
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Buncher
Arrangement which velocity-modules and thereby forms bunches of electrons in the electron beam current passing through it. Bunching would be ideal if the bunches contained electrons all having the same beam velocity. Also called input gap.
Also see
Buncher gap
See
Bunching
The process of forming a steady electron beam into a succession of electron groups, or bunches. The result of interaction between an alternating electric field at the mouth of a cavity and an electron beam passing close by.
Bunching angle
Transit delay or phase angle between modulation and extraction of energy in a bunched beam of electrons.
Bundle conductor
Two or more overhead line conductors, suitably spaced to avoid Brush discharge loss, forming a phase, replaces a single large conductor.
Bundled out
Trucker slang for Trailer is fully loaded as in "As bundled out as I am those hills will really slow me down."
Bungee cord
A rubber tie down strap of various lengths (usually 10 mm diameter) with a metal hook on each end. Most are covered with fabric. The hooks are often plastic coated to minimize scratching. Some have an extra hook attached in the middle. Others are linked with a second cord to produce an X-shape. They are used to secure objects to a luggage rack.
Also see
Bungee net
A specialized bungee cord shaped in the pattern of 25 squares with plastic covered hooks on two opposite sides of the net. It is used to secure objects to a luggage rack.
Also see
Bunk
  1. A set of vertical metal cradle brackets or posts mounted on a log truck or trailer to hold logs in place. Also called bolsters.
  2. A sleeper on a truck
  3. A built-in bed on a ship.
Bunker
  1. Space where ice or cooling element is placed in commercial installations.
  2. A storage space for coal or oil fuel.
Bunker capacity
The capacity of a space in a ship used for carrying fuel. It is calculated at a fixed rate of stowage per unit volume, according to fuel, and allowances for obstructions are made in percentage.
Bunker Fuel Oil
Heavy, residual fuel oil used in ships.
Bunker fuels
Fuel supplied to ships and aircraft, both domestic and foreign, consisting primarily of residual and distillate fuel oil for ships and kerosene-based jet fuel for aircraft. The term international bunker fuels is used to denote the consumption of fuel for international transport activities. Note: For the purposes of greenhouse gas emissions inventories, data on emissions from combustion of international bunker fuels are subtracted from national emissions totals. Historically, bunker fuels have meant only ship fuel.
Bunkers
Fuel consumed by the engines of a ship.
Bunsen Burner
See
Bunt
A maneuver in which an aircraft performs half an inverted loop, i.e., the pilot is on the outside where he experiences Negative g
Buoy
See
Buoyancy
  1. The ability of an object to float
  2. The lifting power demonstrated when an object is immersed.
  3. The apparent loss in weight of a body when wholly or partly immersed in a fluid, due to the upthrust exerted by the fluid.
Also see
Buoy-to-buoy
See
Buran
Soviet space shuttle which undertook a successful unmanned flight in November 1988, later missions were cancelled due to funding problems
Burden
The load on an instrument transformer. It is usually expressed as the normal rated load in volt-amperes, or as the impedance of the circuit fed by the secondary winding.
Bureau
A credit report on a customer who is about to purchase a vehicle.
Bureau of land management
(BLM) The United States government agency within the U.S. Department of the Interior which has divided trails into four classes
  • Type I is at least 213cm wide (enough for a family vehicle), paved, easy to traverse.
  • Type II is also at least 213cm wide, not paved, but is usually improved. However it may be rough or rutted and contain Washboards. It is best traveled by high-clearance 4WD vehicles.
  • Type III is a narrow unimproved dirt road, often with rocks, steep hills, and mud over which only 4WD should use.
  • Type IV trails are for Mountain bikes, dirt bikes, and ATVs. 2WD or 4WD vehicles are not allowed.
Bureau of Transportation Statistics
(BTS) An organization which compiles, analyzes, and publishes statistics relevant to the US nation's transportation system. Created to improve the knowledge base for public decision-making and to improve public awareness of the nation's transportation system, BTS collects information on transportation and other areas as needed. The Bureau's largest data collection programs are the Commodity Flow Survey and the American Travel Survey, conducted jointly with the Bureau of the Census to identify where freight and people go by all modes of transportation.
Burglar
See
Burial site
Place for the deposition, usually in suitable containers, of radioisotopes after use, contaminated material or radioactive products of the operation of nuclear reactors. Also called graveyard.
Burn
Controlled firing of rocket engine for adjusting course and re-entry initiation.
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Burned metal
A term occasionally applied to the metal which has been combined with oxygen to the end that some of the carbon has been changed into carbon dioxide and some of the iron into iron oxide.
Burnable poison
Neutron absorber introduced into a reactor system to reduce initial reactivity but becoming progressively less effective as burn-up proceeds. This helps to counteract the fall in reactivity as the fuel is used up. Boron-10, which is transmuted into helium by neutron capture, has been used in the form of borosilicate glass placed in empty control-rod guides.
Burned valves
Valves that have become pitted so that they do not close properly.
Burner
  1. A device which tends to consume a lot of material.
  2. Device in which burning of fuel takes place.
  3. A device for the final conveyance of the gas, or a mixture of gas and air, to the combustion zone.
Also see
Burner firing block
Unit made from refractory material that fits into a furnace wall at the burner position, having a nozzle-protecting recess at back and a tunnel on the firing side. It is called quarl in oil-firing practice.
Burner head
That portion of a burner beyond the outlet end of the mixer tube that contains the ports.
Burner loading
Potential heat that can be liberated efficiently from a burner. Expressed in kilowatts or Btu h-1
Burner turndown factor
Minimum gas rate at which a burner is capable of stable flame propagation without the flame flashing back to the air-gas mixing point or blowing off from the burner nozzle or head.
Burner valve
A manually or mechanically operated valve which permits control of the flow of fuel.
Burning
  1. The violent combination of oxygen with any substance to produce heat.
  2. The action of consuming something to produce heat, i.e., Combustion.
  3. The heating of an alloy to too high a temperature, causing local fusion or excessive penetration of oxide, and rendering the alloy weak and brittle.
    Also see
  4. The action of erosion or eating away. Electrical contacts are burning when they wear away; exhaust valves are burning when they pit and don't close properly.
  5. Flame cutting.
Also see
Burnish
  1. To bring a surface to a high shine by rubbing with a hard, smooth object.
  2. The process of breaking-in new brake pads or shoes so the linings conform to the disc or drum friction surfaces.
  3. The initial seating process in which the brake shoes or pads wear to conform to the exact contours of the brake drum or disc.
Burn mark
Molding defect found on polymer surfaces caused by adiabatic compression of gas trapped in mold cavity by advancing melt front
Burnout
Sudden failure of any device, caused by excessive current, leading in turn to overheating; may also be due to failure of artificial cooling in any electronic assembly or sub-assembly.
Also see
Burnout velocity
The maximum velocity achieved by a rocket when all the propellant has been consumed.
Burn rate
See
Burn rubber
The action of rapid acceleration where the wheels make rapid rotation, but there is only very little Momentum. As a result, the driving wheels leave some rubber behind on the pavement.
Also see
Burnt metal
Metal which has become oxidized by overheating, and so is rendered useless for engineering purposes.
Burnt valves
See
Burn-up
  1. In nuclear fuel, amount of fissile material burned up as a percentage of total fissile material originally present.
  2. Of fuel element performance, the amount of heat released from a given amount of fuel, expressed as megawatt or gigawatt-days per tonne.
Burr
  1. A roughness left on a cut or punched metal. A rough edge or Ridge.
  2. A rotary tool with cutting teeth like a file.
Burred wheel
A wheel which has metal slivers or roughness around the edge of the rim.
Burr walnut
A wood veneer used for dashboards and door trim on some cars.
Also see
Burst
  1. To explode and suddenly lose all the air in a tire.
  2. A defect, often very small, in fuel cladding or sheeting which allows fission products to escape.
  3. Unusually large pulse arising in an ionization chamber caused by a cosmic ray shower.
  4. Short period of intense activity on an otherwise quiet data channel.
  5. Sudden increase in strength of received radio signals caused by sudden changes in the ionosphere.
    Also see
Burst-can detector
An instrument for the early detection of ruptures of the sheaths of fuel elements inside a reactor. Also called burst-cartridge detector or leak detector.
Burst cartridge
Fuel element with a small leak, emitting fission products. Also called burst slug.
Burst-cartridge detector
See
Burst slug
See
Bury the needle
Going beyond the displayed maximum speed. For example, an analog speedometer may show speeds from zero to 137 kph on its display. When the needle reaches the maximum displayed point, it does not rest there as the vehicle accelerates further. The needle is attached to a spring allowing the needle to keep winding up. The bezel around the speedometer may hide the needle so that it goes beyond the line of sight and is considered buried.
Bus
  1. A large public or private passenger vehicle used for transporting many (at least 10) passengers.
    Also see
  2. The part of the payload of a space exploration vehicle which contains the atmospheric (re-)entry probes, or a universal platform for diverse space experiments and applications.
  3. A Bus-bar which is a heavy electrical Conductor used to carry or make a mutual connection between several circuits.
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Bus-bar
  1. A heavy Conductor used to carry or make a mutual connection between several circuits. Also called a bus.
  2. Length of constant-voltage conductor in a power circuit. Normally of rigid copper construction and located in a power station or substation.
  3. Supply rail maintained in a constant potential (including zero or ground) in electronic equipment.
Bus Boarder
Infrastructure to assist people to board a bus.
Bus-coupler switch
A switch or circuit breaker serving to connect two sets of duplicate bus-bars.
Bush
  1. British term for Bushing.
  2. A hardened cylindrical inset in a drilling jig to position a drill or reamer accurately.
Also see
Bush-hammering
The operation of dressing the surface of stone or concrete with a special hammer having rows of projecting points on its striking face for decoration or to improve bonding to the next placement of further concrete.
Bushing
  1. A protective Liner or sleeve that cushions noise, Friction, or movement. Suspension bushings are often made from two pipes (one inside the other) with a sleeve of rubber in the space between the two pipes.
  2. Rubber bushings on the Suspension system should be lubricated regularly.
  3. A bearing for a shaft, spring Shackle, Piston pin, etc., of one piece construction which may be removed from the part.
  4. An insulator which enables a live conductor to pass through a grounded wall or tank (e.g., the wall of a switch house or the tank of a transformer.)
Also see
Business coupe
A basic low-end, two-door coupe. Often with only a front bench seat and no back seat. Favored by salesmen because the back could be loaded with samples.
Business Route
(Bus Rte) An alternate road which leads through the center of a municipality where most of the "downtown" business establishments are located.
Bus-line
A cable, extending the whole length of an electric train, which connects all the collector shoes of like polarity. Also called power line
Bus-line couplers
Plug-and-socket connectors to join the bus-line of one coach of an electric train to that of the next.
BUS N
Acronym for Bus Negative -- the negative terminal.
Bus Operators Charter
Document setting out standards of service provision.
Bus Operators Forum
Meeting group of local bus operators.
BUS P
Acronym for Bus Positive -- the positive terminal.
Bus Rte
Abbreviation for Business Route
Buster
See
Bustleback
Bustleback

Bustleback

A car body with an attached luggage compartment or the appearance of one such as seen on the 1982 Cadillac Seville.
Bustle pipe
Main air pipe surrounding blast furnace, which delivers low pressure compressed air to tuyères.
Bus-wire coupler
A flexible connection between the coaches of an electric train for maintaining the continuity of bus-wires which run throughout the train-length.
Busying
See
Busy intersection
A road junction where there is a lot of traffic and may be controlled by signal lights or not. Usually a place where accidents are more likely to occur.
Butane
A petroleum gas easily liquefied under pressure, recovered from natural gas. Used as a low-volatility component of motor gasoline, processed further for a high-octane gasoline component, used in LPG for domestic and industrial applications and used as a raw material for petrochemical synthesis. Often used as engine fuel in trucks.
Also see
Butex®
Trade name for diethylene glycol dibutyl ether, used for separating uranium and plutonium from fission products.
Buthocrome
Particular groups of atoms in organic compounds which have the effect of lowering frequency of the radiation absorbed by these compounds.
Butt
  1. The joint between two plates or other members which meet edge to edge.
  2. The square ends of a piston ring.
Butt connector
A solderless wire connector used to permanently join two wire ends together.
Butted tubing
Tubing whose outside diameter remains constant but whose thickness is reduced in midsection where less strength is needed.
Butterfly
Term used in metal extrusion where an open U shape is first made and the sides then folded closer to make a vertically sided U. This enables the die to be much stronger because the narrow section to form the inside of the U can have a wider base.
Also see
Butterfly curve
The strain versus applied field curve of ferroelectrics.
Butterfly valve
A nut with wings to be turned by thumb and finger. Sometimes called a Wing nut.
Butterfly valve
  1. A small metal Disc located in the Carburetor that controls the flow of air into the Carburetor. It is so named due to its resemblance to the insect of the same name.
  2. A disk turning on a diametral axis inside a pipe; used as a throttle valve in a gasoline engine.
  3. A valve consisting of a pair of semicircular plates hinged to a common diametral spindle in a pipe; by hinging axially, the plates permit flow in only one direction.
Buttermilk
Trucker slang for beer as in "When I get home I'm gonna get me some buttermilk."
Butt joint
  1. A piston ring gap in which the two ends of the ring are squared off.
  2. A weld where the two panels are not overlapped but fit against each other end to end.
Butt-jointed
See
Butt-nosed
A colloquial term for a Cab-Over-Engine truck
Buttock
  1. The distance away from the centerline
  2. An intersection of a molded surface with a vertical longitudinal plane.
Buttock planes
Longitudinal sectional planes drawn through a ship's form; used for laying-off in the molding loft, and for calculation of volumes, etc.
Button
A small disk or knob which activates something electrical when it is pressed such as a starter button.
Also see
Button Die
Small adjustable dies for screw machines and similar work, supported in a ring holder.
Button head
A bolt with a Round head
Button-headed screws
Screws having hemispherical heads, slotted for a screwdriver. Also called half-round screws
Button microphone
Small microphone which can be fitted in the buttonhole.
Buttons
See
Button Socket Head Cap Screw
Button Socket Head Cap Screw

Button Socket Head Cap Screw

A socket cap screw with a wider dome-shaped head and lower profile than a socket cap screw. Used when a wider bearing surface or a smoother, more finished appearance is desired. Button head cap screws do not afford the strength of socket head cap screws and are designed for light fastening applications.
Butt Rally
See
Buttress
  1. A thick rubber reinforcement in the shoulder of a tire. It provides support at the edge of the tread, limits shoulder area flexing, and protects the shoulder of off-road tires.
  2. A supporting pier built on the exterior of a wall to enable it to resist outward thrust.
Also see
Buttress screw-thread
A screw-thread designed to withstand heavy axial thrust in one direction. The back of the thread slopes at 45°, while the front or thrust face is perpendicular to the axis.
Buttressed thread
A screw thread with one vertical and one inclined flank.
Butt strap
A plate that overlaps two pieces that are pressed up against each other edge to edge (i.e., butted) in order to secure them. The two butted pieces may be welded to each other or the butt strap could be welded to the pieces or simply bolted to them.
Butt-welded tube
Tube made by drawing mild steel strip through a bell-shaped die, so that the strip is coiled into a tube, the edges being then pressed together and welded.
Butt-welding
The joining of two plates or surfaces by placing them together, edge to edge, and welding along the seam thus formed.
Also see
Butyl
A non-porous synthetic rubber used in making inner tubes and tubeless tire liners and as a base for one type of adhesive. It has poor resistance to petroleum oils and gasoline but excellent resistance to vegetable and mineral oils, and to such solvents as acetone, alcohol, phenol, and ethylene glycol. Also has excellent resistance to water and gas adsorption and sunlight.
Also see
Butyl Alcohol
Alcohol derived from Butane that is used in organic synthesis and as a solvent.
Also see
Butylene
(C4H8) An Olefinic hydrocarbon recovered from refinery processes.
Butyl Ether
See
Butyl rubber
A synthetic rubber used as a base for one type of adhesive. It has poor resistance to petroleum oils and gasoline but excellent resistance to vegetable and mineral oils; to such solvents as acetone, alcohol, phenol, and ethylene glycol; and excellent resistance to water and gas adsorption and sunlight.
Butyl tube
The typical material for tubes. Inexpensive, easy to repair.
Buxton certification
The certification of the suitability of electrical equipment for use in an atmosphere in which fire or explosion hazards are present.
Buy at end-of term interest rate
The effective net interest rate for the lease if, at the end of the lease, the car is purchased at the end-of-lease purchase price.
Buying decisions
The act of determining whether or not a product purchase or repair, will be made, and/or which product or service will be purchased.
Buy rate
The interest rate that banks or financing institutions will charge on all vehicle contracts being financed. It is a secret number between the bank and the dealer which is the real amount of the interest rate that the loan starts out at before the dealer increases it for its own extra profit.
Buzz
  1. Severe vibration of a control surface in transonic or supersonic flight caused by separation of the airflow due to compressibility effects.
  2. To interfere with an aircraft in flight by flying very close to it.

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