- HAI
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- Abbreviation for Heated air inlet system
- Abbreviation for hot air intake
- Hairline crack
- A tiny stress crack which forms due to strains in the material or extreme temperature differences; as opposed to crazing, a single crack of this type will often occur alone
- Hair pin cotter
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Hair pin cotter
See- Hitch pin clip where one leg is straight
- Hairpin valve spring
- A valve spring formed from a wire or metal strip bent to form two levers emanating from a half-loop or coil; used on some classic cars and motorcycles
- Half dog point
- The same as a dog point but half as long; used on short screws for the same purposes as the dog point, but in a shallower hole or slot.
- Half dog point socket set screw
- A headless socket set screw threaded the entire length. It has a hexagonal drive at one end and a protruding tip with a flat surface at the other end.
- Half link
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Half link
- Half-moon key
-
Half-moon key
- Half shaft
- A rotating shaft that transmits power from the final drive unit to one side of the drive wheels, but usually refers to the two shafts that connect the road wheels to the final drive with Independent rear suspension or Front-wheel drive as opposed to the axle shafts of a live rear axle. Also called an Axleshaft
- Half-step gearing
- A Gearing system of a bicycle in which a shift between chainrings in a double chainring set is equivalent to half a gear step on the freewheel.
- Halftrack
-
Halftrack
- Hall effect
- In electrical conductors where electric current flows perpendicular to a magnetic field, a so-called Hall voltage is produced perpendicular to the direction of current flow and to the magnetic field
- Hall-effect sensor
- A Hall generator
- Hall-effect switch
- A Hall vane switch
- Hall element
- A pulse generator that makes use of the Hall effect and consists of a rotor with vanes, a conductive element with a permanent magnet and the Hall IC. Also called Hall generator. When the air gap is unobstructed, a Hall voltage is generated; when a vane stands in the air gap, the magnetic flux cannot reach the Hall IC. Hall generators used as ignition pulse generators have as many vanes and Hall windows as the engine has cylinders, dwell being determined by the width of the vanes. Hall generators used in electronic-map ignition systems to provide the engine starting signal have only one Hall window
- Hall generator
- A pulse generator that makes use of the Hall effect and consists of a rotor with vanes, a conductive element with a permanent magnet and the Hall IC. Also called Hall element.
- Hall IC
- A solid state device with the actual Hall generator and integrated circuits for voltage amplification and potential reversal, producing the pulses for the control unit
- Hall module
- A Hall IC
- Hall sensor
- A Hall generator.
- Hall vane switch
- A switch that makes use of the Hall effect. When the air gap is free, a magnetic field acts on the Hall IC and the Hall voltage reaches its maximum (high). When a rotor vane obstructs the air gap, shielding the Hall IC from the magnetic flux, the Hall voltage reaches its minimum (low). The signal produced is a square wave
- Halo car
- An automobile intended to stimulate interest in or lend prestige to an automobile line. Example: The Viper is a halo car for Dodge.
- Halogenated substances
- A volatile compound containing halogens, such as chlorine, fluorine or bromine.
- Halogen bulb
- A quartz light bulb with a tungsten filament surrounded by a trace of a halogen gas, such as iodine, bromine, fluorine, chlorine, astatine. A halogen bulb gives off a brighter light than conventional bulbs.
- Halogen headlamps
- Tungsten-halogen bulb used in sealed beam unit or as separate bulb in composite headlamp
- Halogen headlight
- High intensity reflector with inner halogen bulb, precision lens, and 3-prong attachment. Don't touch the glass of a halogen bulb with your fingers. The oil left on the glass will cause the glass to break or reduce the life of the bulb. If the glass is accidentally touched, it may be cleaned with methylated spirits or rubbing alcohol on a soft cloth
- Halogen lamp
- A type of Incandescent lamp that lasts much longer and is more efficient than the common incandescent lamp. The lamp uses a halogen gas, usually iodine or bromine, that causes the evaporating tungsten to be redeposited on the filament, thus prolonging its life.
- Hamlin switch
- A suspended-mass-type sensor used in new air bag systems; avoids the ecological problems associated with the earlier mercury-type switches
- Hammer
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- To hit with a hammer.
- To ride hard and fast.
- Someone who rides hard and fast.
- Trucker slang for the accelerator pedal as in 'When we get past this parking lot we can really hit the hammer.'
- A hand tool with a head (usually metal) and a handle. It is used to force one item against or through another. Several types of hammers are available See
- Air hammer
- Ball-pane Hammer
- Ball peen hammer
- Ball pien hammer
- Blacksmith hammer
- Body hammer
- Boilermakers Hammer
- Brass hammer
- Bricklayer hammer
- Bumping hammer
- Chipping hammer
- Claw hammer
- Club hammer
- Copper-faced hammer
- Curved pein and finishing hammer
- Fender bumping hammer
- Finish hammer
- Grooving hammer
- Machinists' hammer
- Nail hammer
- Nylon hammer
- Panel hammer
- Peen hammer
- Pein hammer
- Pick and finishing hammer
- Pick hammer
- Planishing hammer
- Prospector's pick
- Reverse curve panel hammer
- Ripping hammer
- Riveting hammer
- Rotary hammer
- Rubber mallet
- Shingler's hammer
- Shrinking hammer
- Sledge hammer
- Slide hammer
- Soft face hammer
- Tack hammer
- Tile setter hammer
- Tinner's hammer
- Two-way hammer
- Water Hammer
- Welding hammer
- Wide-nose peen hammer
- Wing bumping hammer
- Wood mallet
- Hammerform
- A shaped wooden block used in panel beating, on which a desired form is produced by hammering
- Hammer welding
- Metalworking technique that includes gas welding, preferably without the use of filler rod, followed by hammer and Dolly work on the welded joint to smooth out any remaining imperfections
- Handbrake
- A brake operated by a hand lever. It may also refer to the Parking brake.
- Handbrake turn
- 180° turn achieved by applying the handbrake (acting on the rear wheels) hard when the vehicle is starting to turn
- Handbrake warning light
- A light on the instrument panel that illuminates when the handbrake is applied; on most new cars it has been superseded by a multifunction brake warning light
- Hand crank
- Before Cadillac invented and first produced electric starters, engines were started by means of a handle which was inserted into the front of the engine and rotated manually. After 1930 it became obsolete.
- Hand cycle
-
Hand cycle
- Hand drill
-
Hand drill
- Handed
- Something that is made for a specific side of a unit. For example, left hand arm rests are not interchangeable with right hand arm rests.
- Hand file
- A flat File for shaping metal, with a rectangular cross section, constant blade width and one smooth edge
- Handivan
- A large van designed for transporting disabled people and their wheelchairs. See Invalid-carriages
- Hand lapped valves
- A process of grinding valves by hand so that there is a perfect match between the valve and its seat.
- Handle
-
- The reaction of a vehicle under a particular circumstance, especially regarding cornering, roadholding, and maneuvering.
- To deal with or to cope with (e.g., 'the tires can handle 50 psi' means the tires can withstand pressure up to 50 psi).
- A CB user's code name.
- Handlebar
- A steering device found on bicycles and motorcycles. Grips, brake levers, and shifters, etc. are attached to the handlebar.
- Handlebar bag
-
Handlebar bag
- Handling
-
- The relative ability of a vehicle to negotiate curves and respond to road conditions. It is a factor of the weight of the vehicle, the suspension, tires, air flow, etc.
- The labor involved in moving product received from the trailer into the warehouse dock and then into the storage location on the 'IN' and moving the product out of the storage location and into a staging location to then be loaded onto a trailer on the 'OUT'. The Warehouse Forklift / Clamp Operator moves product IN and OUT. If additional handling is involved such as opening on days off, pick packing etc., that are not the normal handling as defined in the warehouse contract, these would be defined as additional accessorial charges for handling.
- A single pick-up, movement and set-down of a loaded or empty pallet.
- Hands-free
- A car cell phone that allows the driver to dial and talk on the phone without handling the phone.
- Hand shield
- An eye and face protector held in the hand. It enables a person to look directly at the electric arc through a special lens without being harmed.
- Hanger
-
- A flexible ring or strap to hold a pipe, e.g., an exhaust pipe.
- A mounting bracket, e.g., a Spring hanger for a Leaf spring.
- A component of sighting point gauges, used to install the gauge at the vehicle chassis.
- Device attached to walls or other structure for support of pipe lines.
- Hanger Bolt
-
Hanger bolt
- Hangover
- A modification of custom cars with separate chassis, e.g., pick-ups, which raises the floorpan and lowers the body, to give the impression that the body has been pulled down over the chassis right down to street level
- Hard anodizing
- A special type of anodizing adapted to the production of thick, hard, abrasion-resistant films
- Hard code
- A type of trouble code that causes the ECU to disengage the ABS and not re-engage it until the problem is repaired
- Harden
-
- The action of turning from a liquid to a solid.
- To set or to cure.
- The action of making the surface a metal tougher.
See
- Hardenability
- In a ferrous alloy, the property that determines the depth and distribution of hardness induced by quenching.
- Hardened Steel Nail
- A heat treated and tempered steel pallet nail with a MIBANT angle between 8 and 28 degrees.
- Hardening
-
- The process of paint, epoxy, or glue becoming hard. The drying or hardening of paint film goes through several stages. The first stage is called dust-free; at this stage, the paint has hardened sufficiently to prevent dust from becoming embedded in the paint film. The second stage is called touch-dry; at this point, the paint film can actually be touched with light finger pressure. The third and final stage is referred to as hard-dry; at this point, the paint film is hard enough to polish.
- A method of heat treating metals by heating to a temperature within, or above, the critical range, holding at that temperature for a given time, and then cooling rapidly, usually by quenching in oil or water.
- Hardening media
- A liquid into which steel is immersed in order to harden the steel. Usually involves cold water, brine, oil, and special polymers.
- Hardness
-
- The toughness of the surface of a metal. Normally stated in terms of Rockwell or Brinell scale of measurement, hardness shows resistance of a fastener to rough marks and abrasions, can indicate yield strength and brittleness, and has a direct relationship to tensile strength in alloy steel fasteners. However, for stainless, brass, and silicon bronze, the correlation between hardness and tensile or yield is tenuous with no definite relationship. Case-hardening uses surface heat treatment on ferrous material to cause a harder outside surface than the center. Through-hardening hardens the entire fastener. Bright hardening calls for heat treatment without oxygen, so no oxides are formed on the material surface.
- Resistance to plastic deformation by indentation, penetration, scratching or bending.
- Chain hardness is typically measured in Vickers, Brinell or Rockwell.
- Hard pedal
- A loss in braking efficiency so that an excessive amount of pressure is need to actuate brakes
- Hard points
- Specific locations, usually called out on a full-sized body draft, of points that have to be adhered to when designing surfaces. Hard points include axle centerlines, seats, pedal locations, roof and sill heights, luggage-compartment dimensions, etc.
- Hard shoulder
- A part of the road that is divided by broken or continuous yellow lines from the rest of the road and should be used only by certain road users in certain situations
- Hard solder
- Uniting two pieces of metal with a material having a melting point higher than soft solder e.g., silver soldering
- Hard spots
- Shiny bluish/brown glazed areas on a brake drum or disc friction surface, caused by extreme heat. Excessive heat has changed their molecular structure. Hard spots can usually be removed by resurfacing

- Hardtop
-
- A two-door or four-door vehicle without a center door post, i.e., no B-post. It gives the impression of uninterrupted glass along the side of the car. The term is derived from hardtop convertible. Other generic names have included sports coupe, hardtop coupe, or pillarless coupe. In the face of proposed rollover standards, nearly all automakers turned away from the pillarless design to a pillared version by 1976-77.
- A removable top made from fiberglass or steel that replaces the soft-top. It is usually painted the same color as the body of the car.
- Hardtop convertible
-
- An automobile with a fixed roof that does not retract into the trunk, but gives the appearance of being a convertible because it does not have B-pillars
- A type of convertible having a removable hard top. Such designs include tops that unfasten and lift off such as early Ford Thunderbirds, Mercedes Retractable hardtop, and the retractable Fords of the late 1950's.
- Harmonic balancer
- Also called Vibration damper. It usually is a solid crankshaft Fan belt Pulley that has a weight ring bonded by rubber to the inner crankshaft-mounted ring. The outer ring absorbs and cancels out crankshaft vibrations that otherwise might cause the crankshaft to break. Formerly, two gearwheels carrying an unbalanced weight, mounted in bearings below the middle main crankshaft bearing, driven at twice engine speed and rotating in opposite directions to counterbalance the secondary vibrations in a four-cylinder reciprocating engine.
- Harmonic balance wheel
- A grooved wheel attached to the front end of the crankshaft which is connected by accessory belts to the fan, alternator, power steering pump, water pump, air conditioning compressor, and other devices so that the rotating crankshaft can drive these other parts as well. The crankshaft pulley usually has timing marks located on it, and these are necessary for checking and adjusting timing with a timing light.
- Harness
-
- A belt system used with child seats and in cars, consisting of two shoulder belts and two lap belt portions fastened by a central buckle.
- A bundle of electrical wires. For convenience in handling and for neatness, all wires going to certain part of the vehicle are bundled together into a harness. A Wiring harness.
- Harness ties
- Self-tightening nylon straps used to bundle wires into harnesses. Once tightened, they can't be removed unless they are cut
- Harvey wallbanger
- Trucker slang for a reckless driver as in 'That 4-wheeler is a real harvey wallbanger.'
- Hatchback
-
Hatchback
- Hatchback coupe
-
Hatchback coupe
- Hatch coaming
- The vertical plating bounding a hatch for the purpose of stiffening the edges of the opening and resisting water entry
- Hatch Cover
- See Pontoon Hatch Cover.
- Hazard flasher switch
- A switch (usually located on the steering column below the steering wheel) which makes all the signal lights flash simultaneously, to warn other vehicles that your car is disabled or going very slowly down the road. Also called 4-way warning light switch.
- Hazardous location
- Any area or space where combustible dust, ignitable fibers, or flammable, volatile liquids, gases, vapors or mixtures are or may be present in the air in quantities sufficient to produce explosive or ignitable mixtures.
- Hazardous materials
- Commodities classified by the Department of Transportation as hazardous, and which require special handling and documentation. Also known as hazmat.
- Hazardous material tag
- A red tag attached to delivery receipts and COSOs. The tag denotes the type and amount of hazardous material in the shipment.
- Hazardous wastes
- Automotive wastes that are on the EPA's list of hazardous materials or that have one or more hazardous characteristics
- Hazard warning switch
- A switch (usually located on the steering column below the steering wheel) which makes all the signal lights flash simultaneously, to warn other vehicles that your car is disabled or going very slowly down the road. Also called 4-way warning light switch.
- Hazmat
- Abbreviation for Hazardous materials, as classified by the U.S. Environmental Protection Agency (EPA). Transport of hazardous materials is strictly regulated by the U.S. Department of Transportation. Also spelled HazMat