Terms starting with H

Hydroxyalkylamide, the TGIC-free crosslinker used to cure carboxyl polyester powders.

Electrician or amateur who does sloppy, unsafe or out-of-code work, or the work itself. Shop talk

Field name for the portable reference electrode that CP techs carry to take potential readings. Shop talk

The time it takes for half the atoms of a radioactive isotope to decay, a fixed value for each nuclide.

A lab test that rolls a loaded steel wheel over submerged mix samples to measure rutting and moisture damage.

How a fabric feels to the touch: softness, smoothness, stiffness, drape and warmth taken together.

The manual handwheel override fitted to a pneumatic actuator so a valve can be positioned by hand. Shop talk

Laboratory-made paper sheet formed from a pulp sample under standard conditions for testing.

Small surface-mount steel utility box with rounded corners, used for exposed switches and outlets on block walls. Shop talk

In a wire drag sweep, the moment the wire catches on an obstruction, and the obstruction that caused it. Shop talk

To load parts onto hooks or racks at the start of the line. Shop talk

The work of installing every fixture on the light plot, then aiming and shaping each one for the show. Shop talk

Helium that lingers in a leak detector or system after a big hit, holding the signal high and masking small leaks. Shop talk

Shop name for dense firebrick, as opposed to lightweight insulating soft brick. Shop talk

Using HVOF carbide coatings in place of electroplated hard chrome on rods, pins and landing gear.

Shop term for case-hardened, ground gears, as opposed to through-hardened soft gears that are cut to finish. Shop talk

A bolted joint that goes from snug to final torque in very little rotation, typically under about 30 degrees.

An add-on start capacitor and relay that gives a struggling compressor extra torque to start. Shop talk

A steel's ability to form martensite to a given depth, set by its chemistry and grain size, not its hardness.

Dismissive term for unmarked, soft, zinc-plated bolts of unknown origin with no certified strength. Shop talk

Breaking an observed water level or current record into its tidal constituents to find each one's amplitude and phase.

One of the regular cosine waves, each with a period fixed by astronomy, that together make up the tide.

Voltage or current components at whole multiples of the supply frequency, produced mostly by nonlinear loads.

A residential steam boiler piping arrangement that stops a leaking return from draining the boiler below a safe level.

Hot air solder leveling: finish made by dipping a board in molten solder and blowing off the excess.

Heat-affected zone: base metal next to a weld whose structure changed from the heat but did not melt.

A fine, even mist pumped into the air so that light beams become visible on stage or on set. Shop talk

Hot-dip galvanized: coated by dipping in molten zinc, leaving a thick, rugged layer for outdoor steel.

High-density interconnect: boards built with microvias, fine lines and sequential lamination for dense parts.

High-density polyethylene: the stiff, chemically resistant polymer used for most landfill and mining geomembranes.

A split on the edge of a cold-headed bolt head, caused by metal being stretched past its ductility.

BGA defect where a solder ball rests in melted paste but never fuses with it, leaving a hidden weak joint.

The grade symbols and maker's mark stamped on a bolt head, the main clue to its strength once it leaves the box.

The amount of mix carried in front of the screed by the augers, which must stay level and constant.

The compressor discharge or condensing pressure of a refrigeration system.

Pressurized box that spreads stock in a thin, even jet across the full width of the forming wire.

The machine that cold heads fasteners, feeding wire, cutting blanks and striking them in a series of dies.

Energy delivered to a weld per unit length, calculated from amps, volts and travel speed.

A refrigeration system that can reverse its flow to move heat indoors in winter as well as outdoors in summer.

A low-pressure boiler limited to 15 psi steam, or to 160 psi and 250 degrees F for hot water.

The vertical up-and-down motion of a vessel caused by waves, measured and removed from sonar depths.

A hex head or nut wider across the flats than the regular series, used for structural and pressure bolting.

The outer, wide end (heel) and inner, narrow end (toe) of a bevel or hypoid gear tooth.

A sealant bead at the inside edge of the glass where it meets the frame, forming a continuous air and water seal.

A cylindrical gear whose teeth wrap at an angle around the blank, engaging gradually for quiet, strong running.

A coil of diamond-section wire screwed into an oversize tapped hole to repair a stripped thread or armor a soft one.

Soaking sealed parts in pressurized helium so any leak lets helium in, then measuring how much comes back out.

Mass spectrometer tuned to helium that finds and measures leaks by detecting helium drawn into the system.

Outside-in leak test: helium is sprayed on an evacuated part while a detector watches for it inside.

The angle between a helical gear's teeth and its axis, along with the hand, right or left.

How far a tooth's actual path across the face width departs from the intended helix, including crowning.

A helium-neon gas laser, usually red at 632.8 nm, the classic low-power alignment and reference laser. Shop talk

Plant slang for the heavy reinforced plastic sheeting laid on floors and over equipment in contaminated work areas. Shop talk

A gear with two opposite-hand helical tooth sets side by side, so their axial thrusts cancel.

Hexagonal steel grid welded to a shell to hold thin erosion-resistant linings, mainly in refinery cyclones.

Shop name for misalignment between two pipe or plate edges, where one sits higher than the other. Shop talk

A truck fitted with retractable flanged wheels so it can drive on the track as well as on the road. Shop talk

Short-headed hand bender for rigid conduit, and also the threaded fitting that hangs a fixture from a box stud. Shop talk

High-Intensity Discharge: lamps such as metal halide and high-pressure sodium that make light from an electric arc in a pressurized tube.

Alumina-silica brick with more than 45 percent alumina, graded in steps such as 50, 60, 70, 80 and 90 percent.

The main line, as opposed to sidings, yard tracks and branch lines. Shop talk

A safety control that shuts down the burner if pressure or temperature rises above the normal operating range.

A posted area where a person could receive more than 1 mSv (100 mrem) in an hour at 30 cm from a source.

The high-pressure half of a refrigeration system, from compressor discharge through condenser to the metering device.

Shallow coastal flooding that happens when ordinary high tides exceed a local flood threshold, often without a storm.

The range from about 10⁻³ down to 10⁻⁷ mbar, where molecules mostly hit the walls rather than each other.

A signal or radio call meaning proceed at full speed, and the verb for leaving or running fast. Shop talk

The taller of a tidal day's two high waters, the one that matters most on mixed-tide coasts.

Low-density, thick nonwoven made for bulk and trapped air rather than strength, such as fiberfill and padding.

High-potential test: applying a voltage well above working level to prove insulation will not break down. Shop talk

Hot mix asphalt: aggregate and binder mixed hot at a plant, hauled hot and compacted before it cools.

Hot modulus of rupture: the bending strength of a refractory measured at high temperature.

A gear cutter shaped like a worm with gashes across its threads, used on a hobbing machine.

Generating gear teeth with a rotating worm-shaped cutter that turns in step with the blank.

The round polishing fixture that holds a connector square to the lapping film during hand polishing. Shop talk

To remove a large volume of material fast with heavy roughing cuts, without worrying about finish. Shop talk

A locomotive engineer, the person who runs the train. Shop talk

To stay on the main track during a meet while the opposing train takes the siding. Shop talk

Of a sealed system, to keep its pressure low with the pumps valved off; failing to hold means a leak. Shop talk

Pinhole, void or bare spot in a coating that leaves the metal underneath exposed.

A gap in survey coverage where no data was collected, which must be filled before the survey is complete. Shop talk

A skip, void or pinhole in the coating where bare metal is exposed.

A gap, pinhole or thin spot in a membrane or coating where it fails to cover the substrate.

Instrument that finds coating holidays by detecting current flow or sparks through flaws to the metal.

Part of a circuit running from the first box back to the panel, or the arrow on a drawing that shows it.

A dedicated fiber run straight from the central point to one end location, with no splitter or shared path in between. Shop talk

Patches of bare, loosely bound stone with open gaps, left where paste never worked in around the coarse rock.

Shop word for the welding helmet, with the dark filter lens that protects eyes and face from the arc. Shop talk

The wire hangers that hold parts on the conveyor and carry the ground connection. Shop talk

Canadian slang for broken, ruined or beyond saving, whether a part, a machine or a plan. Shop talk

A field water test spraying a controlled stream from a calibrated nozzle at joints and windows to find leaks. Shop talk

A terminal worker who moves, fuels, sands and services locomotives inside the engine facility. Shop talk

Ungrounded, voltage-carrying conductor of a circuit, and as an adjective anything that is live. Shop talk

Shop word for live or energised, and in North America the everyday name for a phase conductor. Shop talk

Radioactive, contaminated or giving a high dose rate, in plant speech; the opposite of clean. Shop talk

Hot-air rework station, or the technique of reflowing parts with a focused stream of heated air. Shop talk

Replacing or retorquing flange bolts one at a time while the line stays in service. Shop talk

A heated, insulated hopper on a truck or trailer that keeps mix hot all day for patching. Shop talk

An overheated wheel bearing on a railcar, a defect that can burn the end off an axle if missed. Shop talk

A trackside scanner that measures bearing temperatures on a passing train and radios a warning if one runs hot.

Coating steel by dipping it in molten zinc, forming bonded zinc-iron layers that protect by barrier and sacrifice.

Surface of a refractory lining exposed to the furnace interior, as opposed to the cold face against the shell.

Spraying powder onto a part that is already hot, so the powder melts on contact and builds a thick film. Shop talk

Floor and craft name for hot melt adhesive, especially sticks fed through a handheld gun. Shop talk

A truckload of concrete that is setting faster than it should, from heat, delay or leftover concrete in the drum. Shop talk

A solid thermoplastic adhesive melted in a tank or gun, dispensed hot and set within seconds as it cools.

Waterproofing built from layers of felt mopped down with hot asphalt, or the act of applying it. Shop talk

Shop name for quench oil run at about 120 to 230 °C for marquenching and low-distortion quenching. Shop talk

A tiny, highly radioactive fragment that can deliver a large localised skin dose if it lands on someone.

The second pass on a pipe weld, run hot and fast right after the root to burn out trapped slag.

Field slang for an asphalt production plant, of either drum or batch type. Shop talk

A rubber-modified asphalt melted in a kettle and squeegeed onto decks as a thick membrane with no seams.

Localized area of active corrosion on a pipeline, or the targeted anodes installed to protect just that spot. Shop talk

A distractingly bright patch in a beam or on a lit surface, brighter than its surroundings. Shop talk

A small spot on piping or equipment with a much higher dose rate than its surroundings. Shop talk

A small region of a beam with much higher intensity than the rest, a common cause of optic damage. Shop talk

Area of a vessel or kiln shell running hotter than normal because the lining behind it is thin or gone. Shop talk

Insulated fibreglass pole used to operate, test or earth high-voltage equipment from a safe distance. Shop talk

A new branch connection made on a pipe or vessel while it stays in service, cutting through a valve.

A tool room inside the controlled area that stores and issues contaminated tools for reuse on radiological jobs. Shop talk

A high-priority train on a tight schedule that dispatchers move ahead of almost everything else. Shop talk

Heat-treat rule of thumb that a part needs about one hour at temperature per inch of its thickest section. Shop talk

The ideal cross-section of a sealant joint: thick at both bond faces and thinner in the middle.

The federal limit on how long train and engine crews may stay on duty before mandatory rest.

Shop word for a loud, droning gear noise, usually from a vehicle axle with a worn or badly set ring and pinion. Shop talk

High-range water reducer, the superplasticizer that makes concrete flow without adding water.

Heating seasonal performance factor: a heat pump's seasonal heating output in Btu divided by its electricity use in watt-hours.

High-speed steel: the tough, hand-grindable tool steel used for drills, taps, lathe bits and some endmills.

Shop name for a lockbolt: a grooved pin with a collar swaged on by a tool, giving a joint that will not vibrate loose. Shop talk

Chart pattern where points cluster unnaturally close to the centerline, usually a sign the limits are wrong. Shop talk

The weight of water vapor per weight of dry air, usually given in grains per pound.

A classification yard where cars are pushed over a small hill and roll by gravity into sorting tracks.

A TXV or control swinging back and forth, alternately overfeeding and starving the evaporator instead of settling. Shop talk

A control valve or loop swinging back and forth around setpoint instead of settling. Shop talk

A tooth combination with no common factor, so every pinion tooth eventually meets every gear tooth.

High-velocity air fuel: an HVOF-style process that burns fuel with compressed air instead of oxygen.

High-velocity oxygen fuel: burning fuel and oxygen under pressure to fire powder at supersonic speed.

Powder that cures an epoxy resin and a polyester resin together, trading some outdoor life for low cost and good flow.

The heat-releasing reaction of cement with water that turns the paste into solid binder.

Reaction of magnesia or lime in a refractory with water or humidity, causing swelling, cracking and dusting.

Flow through a strait or canal driven by the water level difference between its two ends, not by local rise and fall.

Clipped insider word for hydrography, hydrographic surveying, or the survey team itself. Shop talk

A hydrostatic pressure test: filling a valve, piping system or vessel with water and pressurizing it to prove strength. Shop talk

Full-film lubrication in which motion drags oil into a narrowing gap and builds enough pressure to float the load.

Bonding a fiber web by blasting it with rows of very fine, high-pressure water jets that tangle the fibers together.

Delayed cracking in steel welds caused by hydrogen, hard microstructure and stress acting together.

Loss of ductility when atomic hydrogen gets into steel, leading to sudden cracking under stress.

Delayed brittle cracking of hard steel fasteners caused by hydrogen absorbed from plating, cleaning or corrosion.

Loss of ductility in high-strength steel when absorbed hydrogen causes delayed cracking under stress.

A systematic measurement of depths, seabed features and shoreline, made so the results can be charted and trusted by mariners.

Shop and spec clip for hydrostatic head: the water pressure a fabric holds before water comes through. Shop talk

Pressure from standing groundwater against a wall or slab, rising with the depth of water above that point.

A spiral-bevel-like gear pair with the pinion axis offset from the gear axis, standard in vehicle drive axles.

A reading difference at the same input depending on whether that input was approached from below or above.