Machine Shop Slang

Start here: ten words every newcomer needs

Overheard on the job

Real-sounding lines from the floor, translated into plain English.

• Tram the head and indicate the vise in first, I want that bore dead nuts, not close enough for government work.

  TranslationSquare the mill spindle to the table and align the vise with an indicator before cutting, because the hole must be exactly on size, not merely acceptable.

• It's chattering and rubbing at the same time, choke up on the endmill and bump the chip load.

  TranslationThe cutter is vibrating and not taking a proper chip, so shorten how far it sticks out of the holder and increase the feed per tooth.

• Prove it out on single block with your finger on feed hold, the last guy crashed the spindle on that program.

  TranslationRun the new CNC program one line at a time, ready to stop motion instantly, because a previous run drove the tool into something.

• Old Bridgeport's clapped-out but it's skookum, just give it some Kentucky windage for the backlash.

  TranslationThe worn manual mill is sturdy and usable, as long as the operator compensates by feel for the play in its screws.

• Hog it out, leave ten thou, then sneak up on it, take a spring pass and mic it every time.

  TranslationRough away most of the material quickly, leave 0.010 in for finishing, then approach final size in light cuts, repeat the last cut to clear tool deflection, and measure after each.

• Somebody fabricobbled that guard with zap straps and a grinder and paint, this is how you get ants.

  TranslationA safety guard was improvised from scrap, cable ties and cosmetic cleanup, and it is going to cause trouble later.

• Ask the crusty on the four-jaw, the keener has been dialing that part in for an hour.

  TranslationGet help from the experienced veteran, because the eager apprentice has been struggling for a long time to center the part in the independent chuck.

Thous, tenths, gauges and the jokes machinists make about measuring by eye.

• Close enough for government workalso good enough for government work
  Ironic shop saying that a result is good enough to pass, even if it would not satisfy a careful craftsman. Shop talk
• Dead nutsalso dead nuts on, dead on
  Shop slang for exactly on size or perfectly aligned, with no measurable error left. Shop talk
• Dykemalso layout fluid, layout dye
  Shop name, from a trade name, for blue layout fluid painted on metal so scribed lines show up bright. Shop talk
• Eyecrometeralso eyeball, calibrated eyeball
  Joking name for measuring by eye, the calibrated eyeball used when no real gauge is handy. Shop talk
• Gnat's whiskeralso gnat's eyelash, hair
  Clean shop term for a tiny, unmeasured amount, smaller than anyone bothers to put a number on. Shop talk
• Go/no-go gaugealso go/no-go, limit gauge
  A fixed gauge with one end that must fit and one that must not, for fast pass or fail checks.
• Gozintaalso goes-into, gazinta
  Shop slang for the part that goes into another part, from the phrase goes into. Shop talk
• Jo blocksalso gauge blocks, Johansson blocks
  Shop name for gauge blocks: lapped steel or ceramic blocks, accurate to millionths, stacked to make any length. Shop talk
• Kentucky windagealso windage
  Adjusting by experience and feel rather than by the numbers, borrowed from riflemen aiming off for wind. Shop talk
• Micalso mike, micrometer
  Short for micrometer, pronounced mike, and the verb for measuring a part with one. Shop talk
• Nominalalso basic size, nominal size
  The stated target size of a feature before any tolerance is applied.
• Surface platealso granite plate, granite
  A thick slab of granite or cast iron, lapped flat, that every height check and layout line is measured from.
• Tenthalso ten-thousandth, tenths
  One ten-thousandth of an inch (0.0001 in, about 2.5 microns), the unit of precision grinding and fits. Shop talk
• Test indicatoralso DTI, dial test indicator
  A lever-type dial indicator with a swiveling stylus, used to align setups and compare surfaces.
• Thoualso thousandth, thous
  One thousandth of an inch (0.001 in, about 25 microns), the everyday unit of machining talk in inch shops. Shop talk
• Tolerancealso tol, plus-minus
  The total amount a dimension is allowed to vary from nominal and still be a good part.
• Wiggleralso edge finder, wobbler
  Shop name for an edge finder or wobble-tip locator used to find part edges and lines on a mill. Shop talk
• Witness markalso match mark, witness line
  A small deliberate mark that shows how parts were aligned or where an original surface was. Shop talk

Tramming, indicating, fixturing and the CNC habits that keep tools out of the vise.

• 1-2-3 blocksalso 123 blocks, one-two-three blocks
  Hardened, ground steel blocks measuring 1 x 2 x 3 inches, used for setups, squaring and height stacks.
• Bumpalso nudge, tweak
  To make a small adjustment to an offset or position, usually a thou or less, to bring a size in. Shop talk
• Chuck keyalso key, chuck wrench
  The T-handle wrench that opens and closes a geared drill chuck or lathe chuck, never left in the chuck.
• Collet
  A slotted, tapered sleeve that squeezes evenly around a tool shank or bar stock to grip it accurately.
• Crashalso wreck
  To run a tool, holder or spindle into the part, vise or table by mistake, usually at rapid speed. Shop talk
• Feed holdalso feedhold
  The CNC button that stops axis motion instantly while the spindle keeps running.
• First articlealso FAI, first article inspection
  The first good part off a new setup or program, fully inspected before the rest of the run is made.
• Fixturing
  The design and use of fixtures that locate and clamp parts the same way every time.
• Four-jawalso four-jaw chuck, independent chuck
  Shop name for an independent four-jaw lathe chuck, each jaw adjusted separately to center or offset work. Shop talk
• Indicatealso indicate in, dial in
  To align a vise, part or bore to the machine axes using a dial or test indicator. Shop talk
• Kissalso kiss cut
  To touch a tool or grinder to a surface as lightly as possible, removing almost nothing. Shop talk
• Parallelsalso vise parallels, precision parallels
  Matched pairs of ground steel bars used to raise a part in the vise to a known, level height.
• Prove outalso prove-out
  To run a new CNC program cautiously the first time, watching every move to catch errors before they crash. Shop talk
• Single blockalso single-block mode, SBK
  A CNC control mode that runs one line of the program per press of cycle start, used to check moves.
• Sneak up on italso sneak up, creep up on it
  Approach a final dimension with smaller and smaller cuts, measuring between each, so you never go undersize. Shop talk
• Soft jawsalso softies, machinable jaws
  Vise or chuck jaws of aluminum or mild steel, machined in place to cradle a specific part.
• Sweepalso sweep in
  To rotate an indicator in the spindle around a bore, boss or circle to find its center or check alignment. Shop talk
• Touch offalso touch-off, pick up
  To set a tool's position by bringing it to a known surface and recording that point in the control. Shop talk
• Tramalso tram in, tramming
  To square a mill head or spindle to the table so the spindle axis is truly perpendicular. Shop talk
• Work offsetalso fixture offset, work coordinate system
  The stored distance from machine zero to the part zero, so a CNC program runs from the right place.

Feeds, speeds, chip talk and the sounds and colors that say a cut is going right or wrong.

• Air cuttingalso cutting air
  Shop term for a tool moving at feed rate through empty space, wasting cycle time. Shop talk
• Bird's nestalso chip nest, rat's nest
  A tangled wad of long, stringy chips wrapped around the tool, chuck or part on a lathe. Shop talk
• Blue chips
  Steel chips that come off straw to dark blue from heat, read as a sign of how hard a cut is running. Shop talk
• Break edgesalso break all sharp edges, edge break
  A drawing note requiring sharp corners to be slightly chamfered or rounded, usually within a small range.
• Built-up edgealso BUE, edge build-up
  Work material welded onto the cutting edge, which changes the tool's shape and tears the surface finish.
• Chatter
  Self-sustaining vibration between tool and work that screams, leaves a wavy pattern and kills tools.
• Chip loadalso feed per tooth, IPT
  The thickness of material each cutting edge takes per revolution, also called feed per tooth.
• Climb millingalso climb cut, down milling
  Milling with the cutter rotating in the same direction as the feed, so each chip starts thick and ends thin.
• Deburralso debur
  To remove the sharp raised edges and slivers that machining leaves on a part.
• Feeds and speedsalso speeds and feeds
  The spindle speed and feed rate chosen for a cut, set from material, tool and machine.
• Hog outalso hogging, hog it
  To remove a large volume of material fast with heavy roughing cuts, without worrying about finish. Shop talk
• Making chipsalso cutting metal, cutting chips
  Shop phrase for machines actually cutting metal, the productive part of the day as opposed to setup. Shop talk
• Parting offalso parting, cutoff
  Cutting a finished part off the end of the bar on a lathe with a thin blade-shaped tool.
• Peckalso peck drill
  To drill a hole in short steps, backing out between them to clear chips and let coolant in.
• Rubbingalso rub, plowing
  A tool sliding over the work without taking a proper chip, usually because the feed is too light or the tool is dull. Shop talk
• SFMalso SFPM, surface speed
  Surface feet per minute: how fast the cutting edge moves across the work, the basis for spindle speed.
• Single-pointalso single-point threading, screwcutting
  To cut a thread on a lathe with a single-point tool over several passes, rather than with a die or tap. Shop talk
• Skim cutalso skim, cleanup pass
  A very light cut that just cleans up a surface or establishes size without removing much material. Shop talk
• Spring passalso spring cut
  A repeat finishing pass at the same setting to remove the material left behind by tool spring. Shop talk
• Sudsalso soluble oil, coolant
  Shop name for water-soluble cutting coolant, the milky mix of oil concentrate and water. Shop talk
• Work hardeningalso strain hardening
  Hardening of a metal surface by plastic deformation, which makes the next cut much harder on the tool.

The machines, cutters and hand tools of the shop, and their nicknames.

• Adjustable hammeralso crescent wrench, adjustable
  Joke name for an adjustable wrench, after how often it ends up being used to hit things. Shop talk
• Angry pixiesalso pixies
  Tool-teardown slang for electricity, the invisible little creatures that bite when you get careless. Shop talk
• Armstrong methodalso Armstrong power, Armstrong
  Shop joke for doing a job by muscle power alone, with no power feed, hoist or machine help. Shop talk
• Bridgeportalso knee mill, B-port
  Shop name for any vertical turret knee mill, after the brand that made the design standard. Shop talk
• Cheater baralso cheater, cheater pipe
  A length of pipe slipped over a wrench handle for extra leverage on a stuck fastener. Shop talk
• Endmillalso end mill
  A rotating cutter with teeth on its end and sides, the main tool for milling slots, pockets and profiles.
• Gas axealso torch, hot wrench
  Shop name for an oxy-fuel cutting torch, also used for heating seized parts. Shop talk
• HSSalso high-speed steel, high speed
  High-speed steel: the tough, hand-grindable tool steel used for drills, taps, lathe bits and some endmills.
• Insertalso carbide insert, indexable insert
  A small replaceable carbide or ceramic cutting tip clamped in a holder, indexed to a fresh edge when worn.
• Magic smokealso let the smoke out
  Joke that electrical parts run on smoke sealed inside them, because once it gets out they stop working. Shop talk
• Percussive maintenancealso percussive adjustment
  Hitting a machine or part to make it work, dressed up in technical language. Shop talk
• Persuaderalso convincer, big hammer
  Shop name for a hammer, usually a big one, used to convince a stuck part to move. Shop talk
• Pot metalalso monkey metal
  Shop name for cheap, low-melting die-cast alloy, usually zinc-based, that is brittle and almost impossible to weld. Shop talk
• Safety squintsalso squints
  Shop slang for squinting instead of wearing eye protection, and jokingly for safety glasses themselves. Shop talk
• Thumb detectoralso finger detector
  Shop joke name for any pinch point, blade or mechanism that is especially good at finding fingers. Shop talk
• Tool cribalso crib, tool stores
  The controlled storeroom where a shop keeps cutters, inserts, gauges and shared tools, checked out by request.
• Unobtainiumalso unobtanium
  Shop joke for a part or material that is impossible or absurdly expensive to get. Shop talk
• Zap strapalso zip tie, cable tie
  Canadian shop name for a plastic cable tie, the one-way locking strap that holds everything together. Shop talk

The words shops use to praise, judge and mock a tool, a part or a repair.

• Automagic
  Happening automatically by some hidden process nobody fully understands or wants to explain. Shop talk
• Belt and suspendersalso belt and braces
  Using two independent safeguards where one should do, for redundancy or out of extra caution. Shop talk
• Bodgealso bodge job, kludge
  A crude, makeshift repair or piece of work that does the job, but only just. Shop talk
• Bubblegum and baling wirealso baling wire and duct tape, chewing gum and string
  Describes a repair or machine held together by improvised, makeshift fixes that should not still be working. Shop talk
• Cattywampusalso catawampus, cockeyed
  Crooked, askew, out of square or not lined up, said of parts, setups and buildings alike. Shop talk
• Chooch
  To run, work or go properly, as in does it chooch; as a noun, the power or oomph a machine has. Shop talk
• Clapped-outalso clapped, worn out
  Worn out from long hard use, still running but loose, sloppy and well past its best. Shop talk
• Dog's breakfastalso dog's dinner, hot mess
  A complete mess: a badly organized job, a tangled setup or a botched piece of work. Shop talk
• Fabricobblealso cobble together
  To fabricate something by cobbling it together from scrap and whatever is lying around. Shop talk
• Grinder and paintalso a grinder and paint make me the welder I ain't, grind it, paint it
  Shop saying that a grinder and paint make me the welder I ain't, for hiding ugly welds. Shop talk
• Griptionalso grippiness
  Shop blend of grip and traction for how well something holds on, from vise jaws to boot soles. Shop talk
• Hoopedalso hooped up, toast
  Canadian slang for broken, ruined or beyond saving, whether a part, a machine or a plan. Shop talk
• Schmooalso shmoo, gunk
  Shop slang for grease, grime, sludge or any gooey lubricant, whether doing its job or gumming things up. Shop talk
• Scrapalso reject, scrap part
  A part that fails inspection and cannot be reworked, and the verb for rejecting or ruining one.
• Skookum
  Strong, stout and well built, the highest praise for a tool, part or weld; also means really good. Shop talk
• This is how you get antsalso that's how you get ants, do you want ants
  Deadpan warning, borrowed from TV comedy, that a shortcut or design choice will cause trouble later. Shop talk

Who works on the floor, the pranks they pull and the culture around the machines.

• Babysitalso watch it run
  To stand and watch a machine run a job because it cannot yet be trusted to run on its own. Shop talk
• Bumblefudgealso the boonies, the sticks
  Clean slang for the remote middle of nowhere, where a shop is too far from suppliers for an easy fix. Shop talk
• Button pusheralso part loader
  Dismissive name for a CNC operator who loads parts and presses cycle start but does not set up or program. Shop talk
• Clipboard warrioralso clipboard commando
  Shop dig at a manager, auditor or inspector who walks the floor with paperwork but never runs the tools. Shop talk
• Crustyalso old crusty, crusty old machinist
  An old, gruff veteran machinist with a lifetime of skill, strong opinions and little patience for shortcuts. Shop talk
• Good idea fairyalso idea fairy
  The imaginary visitor who brings last-minute changes and bright ideas nobody thought through. Shop talk
• Government jobalso G-job, homer
  A personal project made on company machines and material, on the side or on the clock. Shop talk
• Guys on the toolsalso shop hands
  The tradespeople actually doing the hands-on work, as opposed to supervisors, planners and office staff. Shop talk
• Keeneralso eager beaver
  Canadian slang for an overeager newcomer who volunteers for everything and tries a little too hard. Shop talk
• Left-handed screwdriver
  A tool that does not exist, which new apprentices are sent to fetch as a rite of initiation. Shop talk
• Machinery's Handbookalso the Handbook, the book
  The thick reference book every machinist owns, covering threads, fits, materials, speeds and formulas.
• Shop rat
  Someone who practically lives in the shop, on the clock or off, and is happiest at a machine. Shop talk

Frequently asked questions

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