Same word, different worlds
Bump
Bump turns up in 6 fields: machine shop, electrotechnology, boilers, lighting, asphalt, railroad. Here is what it means to the people in each one.
- 12MsMachine Shop SlangBump in Machine Shop Slang
To make a small adjustment to an offset or position, usually a thou or less, to bring a size in. Changing a wear offset or nudging an axis by a tiny amount, as in bump the offset a half thou. In CNC work it is how operators hold size as tools wear without editing the program. On manual machines it means tapping the handwheel or jog by the smallest increment.
On the job: Diameter's drifting up as the insert wears, bump the X wear offset minus three tenths and keep running.
- 13EtElectrotechnologyBump in Electrotechnology
To energise a motor for a split second to check its direction of rotation before running it properly. Bumping a motor means pressing start and stop almost together so the shaft turns only a few degrees, enough to see which way it spins. It is standard after new terminations or any change to the supply, because a pump, compressor or conveyor driven backwards can be damaged. If the direction is wrong, any two of the three phases are swapped at the motor or the starter.
On the job: Bump the cooling tower fan before you let it run, we just moved the feed onto the new cable.
- 16BoBoilers & BurnersBump in Boilers & Burners
To energize a motor, pump or burner for a second or two to check rotation or operation. Before running a new or rewired pump or burner fan, techs bump it to see which way it spins, since a three-phase motor wired backwards turns the wrong way. Bumping also checks that a feed pump will pick up water or that a damper moves. The word implies a deliberately brief start, not a run.
On the job: Bump the feed pump and watch the coupling, if it's spinning backwards swap two legs at the starter.
- 18LxLighting & Color ScienceBump in Lighting & Color Science
To flash a channel or group to full instantly, usually with a console button, to identify it or for effect. Console operators bump a channel to find which fixture it controls or check that it works, and bump buttons on submasters let them flash groups for musical accents. A bump cue is a zero-time cue that snaps lights on or off. The opposite of a fade, a bump hits hard and is often used at the end of a song or a scene.
On the job: Bump 214 for me, I can't tell which of the two boom units is out.
- 24AsAsphalt PavingBump in Asphalt Paving
To push excess mix off the old side of a joint back onto the hot mat with a lute so the rollers can pinch it in. What a raker does along a longitudinal joint after the paver overlaps the cold edge: pushes the overlapped mix back off the cold side so it sits as a small ridge on the hot side, right at the joint line. The roller then compresses that extra material into the joint, raising density there. Bumping too much leaves a hole at the joint, and broadcasting the excess across the mat leaves loose coarse rock on the surface.
On the job: Just bump it back to the line, don't rake it across the mat, the rock's going to show.
- 30RrRailroadingBump in Railroading
To use seniority to take a job held by someone junior, who is then displaced. When a job is abolished or a senior employee wants a better assignment, that employee can bump a junior one off a job, and the displaced person may bump someone below them, setting off a chain of displacements down the seniority roster. Bumps decide who works days, who works holidays and who lands on the extra board. Being bumped is normal, and nobody takes it personally, at least not out loud.
On the job: They abolished the day goat, so the old head is bumping me off the hump job and I'm back on the extra board.