Industrial Glossary
Clear definitions of technical terms, standards, and acronyms used across bearings, power transmission, pumps, safety, and MRO — helping you buy and maintain with confidence.
Showing 97 of 97 terms
Bearings
22 termsABEC Rating
Annular Bearing Engineering Committee scale (1–9) measuring bearing precision and tolerance. Higher numbers indicate tighter tolerances — ABEC 7 and 9 are used in high-speed precision applications.
Angular Contact Bearing
A ball bearing designed to handle combined radial and axial (thrust) loads. The raceways are offset so the contact angle allows axial load capacity in one direction.
Axial Load
Force applied parallel to the shaft axis (also called thrust load). Bearings must be selected to handle the expected axial forces in the application.
Bearing Cage
A component that separates and guides the rolling elements (balls or rollers) within a bearing. Materials include pressed steel, brass, polyamide, or machined steel.
C3 Clearance
Internal radial clearance greater than normal (CN). C3 bearings have extra room between rolling elements and raceways to accommodate thermal expansion at higher operating temperatures.
Deep Groove Ball Bearing (DGBB)
The most common bearing type — versatile, low-friction design handling radial and moderate axial loads. Found in electric motors, pumps, and general industrial machinery.
Dynamic Load Rating (C)
The constant radial load a bearing can endure for a rating life of 1 million revolutions. A fundamental value used to calculate bearing service life under given operating conditions.
Fretting Corrosion
Surface damage caused by micro-movements between fitted components (e.g. bearing outer ring and housing). Results in reddish-brown oxide debris and can loosen the fit over time.
Housing Bore Tolerance
The acceptable dimensional range for the housing bore that accepts the bearing outer ring. Correct tolerance determines whether the fit is a push fit, transition, or interference.
Interference Fit
A mounting method where the shaft is slightly larger than the bearing bore, requiring pressing or heating to install. Provides secure seating and prevents inner ring creep.
ISO Tolerance Code
Standardised letters and numbers (e.g. k5, m6 for shafts; H7, J7 for housings) defining the permitted dimensional variation. Critical for selecting correct bearing fits.
L10 Life
The number of revolutions (or hours at constant speed) that 90% of a group of identical bearings will survive under specified load. Also called "basic rating life."
Limiting Speed
The maximum rotational speed at which a bearing can operate without excessive heat generation, based on its mechanical design, lubrication, and cage type.
Needle Roller Bearing
A roller bearing using long, thin cylindrical rollers with a high length-to-diameter ratio. Provides high load capacity in a compact radial space — common in gearboxes and automotive applications.
Preload
A deliberate internal compressive load applied to a bearing during installation to eliminate internal clearance. Used on precision spindles to reduce axial play and increase stiffness.
Radial Load
Force applied perpendicular to the shaft axis. Most bearings are primarily designed for radial loads, though many can handle combined loads.
Sealed Bearing (2RS / ZZ)
A bearing fitted with integral rubber or metal seals on one or both sides to retain lubricant and exclude contaminants. Designated by suffixes like 2RS (two rubber seals) or ZZ (two metal shields).
Self-Aligning Bearing
A bearing designed to accommodate shaft misalignment up to approximately 3°. Features a spherical outer ring raceway allowing the inner ring and ball assembly to pivot.
Spherical Roller Bearing (SRB)
Heavy-duty bearing with two rows of barrel-shaped rollers on a spherical outer raceway. Self-aligning, handles very high radial and axial loads — used in mining, aggregates, and heavy industry.
Static Load Rating (C0)
The maximum static load a bearing can withstand without permanent deformation of rolling elements or raceways exceeding 0.0001× the rolling element diameter.
Tapered Roller Bearing (TRB)
Bearing with conical rollers and raceways, designed to handle combined radial and axial loads. Commonly used in wheel hubs, gearboxes, and heavy-duty shaft applications.
Vibration Analysis
A condition monitoring technique measuring bearing vibration signatures to detect early-stage faults, misalignment, or lubrication issues before catastrophic failure occurs.
Power Transmission
17 termsBelt Pitch
The distance between the centres of adjacent teeth on a timing belt (for synchronous drives), or the effective drive length per unit of belt (for V-belts). Determines pulley compatibility.
Chain Pitch
The distance from the centre of one roller to the centre of the next in a drive chain, measured in inches or mm. A #40 chain has ½" pitch; #80 has 1" pitch.
Coupling
A mechanical device connecting two rotating shafts to transmit torque. Types include rigid (precise alignment required), flexible (absorbs misalignment and shock), and fluid couplings.
Drive Ratio
The ratio of the driven shaft speed to the driving shaft speed, determined by sprocket or pulley tooth counts. A 2:1 ratio halves the output speed and doubles the output torque.
Gear Ratio
The ratio of input gear teeth to output gear teeth. A 4:1 ratio reduces output speed to 25% of input speed while multiplying torque by approximately 4× (less losses).
Gearbox Efficiency
The proportion of input power delivered to the output shaft after internal losses (friction, oil churning). Worm gearboxes: 50–90%. Helical gearboxes: 95–99%.
Helical Gear
A gear with angled teeth cut in a helix pattern around the gear body. Quieter and smoother than spur gears due to gradual tooth engagement — widely used in industrial gearboxes.
Inverter (Variable Frequency Drive)
An electronic device that controls AC motor speed by varying supply frequency and voltage. Enables soft starting, speed control, and energy saving — essential for pumps and fans.
Keyway & Keystock
A rectangular slot (keyway) cut into a shaft and hub, with a matching key (keystock) inserted to transmit torque between them. A simple, reliable, and widely standardised coupling method.
Motor Frame Size
A standardised designation (e.g. IEC 90, 132, 160) defining the motor's mounting dimensions, shaft height, and bolt pattern. Enables motor interchangeability between manufacturers.
Output Torque
The rotational force available at a gearbox or motor output shaft, measured in Newton-metres (Nm). Equals input torque × gear ratio × efficiency.
Roller Chain
A power transmission chain using cylindrical rollers on pins to engage sprocket teeth. Standard roller chains conform to ISO 606 — rated by pitch and breaking load.
Service Factor
A multiplier applied to a drive's rated load to account for shock, start/stop frequency, and duty cycle. A service factor of 1.5 means selecting a drive rated 50% above the actual load.
Shaft Misalignment
Angular, parallel, or axial offset between two coupled shafts. Even small misalignment (0.1 mm) dramatically increases bearing and seal wear — alignment should be within manufacturer tolerances.
Torque (Nm)
A rotational force measured in Newton-metres. Torque = Force × radius. At a given power, lower speed means higher torque (and vice versa) — critical for gearbox and motor selection.
V-Belt
A trapezoidal-profile belt running in a matching groove on a pulley. The wedging action of the V-shape increases friction and power transmission capacity. Classical (A, B, C) and narrow (SPZ, SPA, SPB) sections are standard.
Worm Gearbox
A gearbox where a worm screw meshes with a worm wheel, providing high reduction ratios in a compact package. Self-locking at low leads — useful for conveyors. Higher losses than helical designs.
Pumps
15 termsBest Efficiency Point (BEP)
The flow rate at which a pump operates at its highest efficiency. Running a pump away from its BEP accelerates wear and increases energy costs.
Cavitation
The formation and collapse of vapour bubbles in a pumped liquid when local pressure drops below vapour pressure. Causes noise, vibration, and pitting damage to impeller surfaces.
Centrifugal Pump
A pump that uses a rotating impeller to accelerate fluid outward from the centre, converting kinetic energy into pressure. The most widely used industrial pump type for clean liquids.
Diaphragm Pump
A positive displacement pump using a reciprocating diaphragm to move fluid. Ideal for metering, chemical dosing, and handling abrasive or shear-sensitive liquids.
Duty Point
The specific combination of flow rate (m³/h) and head (metres) at which a pump operates in a given system. Selecting a pump to match its duty point is critical for efficiency.
Gland Packing
Compressible sealing material wrapped around a pump shaft to control leakage at the stuffing box. Traditional alternative to mechanical seals, still common on larger pumps.
Head (Pump Head)
The height to which a pump can raise a column of liquid, expressed in metres. Represents the pump's ability to overcome system resistance — not just vertical lift but also pipe friction and fittings.
Impeller
The rotating component of a centrifugal pump that transfers energy from the motor to the fluid. Impeller design (closed, semi-open, open) determines flow, pressure, and solids-handling capability.
Mechanical Seal
A precision sealing device on a pump shaft using two flat faces — one rotating, one stationary — running against each other to prevent leakage. Modern replacement for gland packing.
NPSH (Net Positive Suction Head)
The minimum pressure required at the pump suction to prevent cavitation. NPSH Available (system) must exceed NPSH Required (pump) by a safe margin.
Positive Displacement Pump
A pump that moves fluid by trapping a fixed volume and forcing it into the discharge. Produces consistent flow regardless of pressure — ideal for viscous fluids, dosing, and high-pressure applications.
Progressive Cavity Pump
A positive displacement pump with a helical rotor turning inside a stator. Delivers smooth, non-pulsating flow — excellent for viscous, abrasive, or solids-laden fluids.
Submersible Pump
A pump designed to operate fully submerged in the pumped liquid. Motor is sealed within a watertight housing — commonly used for boreholes, sewage, and dewatering.
Variable Speed Drive / VSD
An electronic controller that varies pump motor speed to match demand. Reduces energy consumption by avoiding throttling — typically saves 20–50% compared to fixed-speed operation.
Wear Ring
A replaceable ring fitted to the impeller or casing of a centrifugal pump. Sacrificial component that maintains close clearance — protects the more expensive impeller and casing from wear.
Safety & PPE
13 termsCE Marking
The CE mark on PPE indicates the product meets EU safety directives. All PPE sold in the UK/EU must be CE marked. Post-Brexit, UKCA marking applies for goods sold in Great Britain.
Class 1 / Class 2 / Class 3 Hi-Vis
EN ISO 20471 visibility classes based on the area of fluorescent and retroreflective material. Class 3 is the highest — required for road workers and high-traffic zones.
Cut Resistance Level (A–F)
ANSI/ISEA 105 scale rating glove cut resistance from A1 (minimal) to A9 (maximum). EN 388 uses a separate scale (a–f). Always match cut level to the actual hazard.
DSE (Display Screen Equipment)
Any alphanumeric or graphic display screen used in work. DSE regulations require employers to assess workstations and provide breaks, eye tests, and adjustable equipment to prevent RSI.
EN 388
European standard for protective gloves against mechanical risks. Tests for abrasion, cut, tear, and puncture resistance. Updated 2016 standard also includes impact protection (P rating) and TDM cut resistance.
EN ISO 20345
The European standard for safety footwear. Defines basic safety requirements (S1, S2, S3) and additional performance (SB, S1P, S3 with penetration resistance, ankle protection, waterproofing, etc.).
LOTO (Lockout/Tagout)
A safety procedure requiring energy sources (electrical, pneumatic, hydraulic) to be isolated and locked before maintenance. Prevents accidental machine startup — LOTO kills people every year when ignored.
P3 Filter (Respiratory)
The highest efficiency particulate filter rating under EN 143 — filters ≥99.95% of airborne particles including fine dusts, metal fumes, and biological agents. Used on half-face and full-face respirators.
PPE (Personal Protective Equipment)
Equipment worn to protect against health and safety risks at work. Governed by the PPE at Work Regulations 1992 (amended 2022). Includes head, eye, hearing, respiratory, hand, foot, and body protection.
RPE (Respiratory Protective Equipment)
Any device worn to protect the wearer from inhaling hazardous substances. Selection must be based on the substance, concentration, and exposure duration — always check the assigned protection factor (APF).
S3 Safety Boot
Under EN ISO 20345 — includes all S1P features plus: anti-penetration midsole, waterproof upper, and full closed seat region. The most comprehensive standard safety footwear rating.
SWL (Safe Working Load)
The maximum load that lifting equipment, slings, or fixings are designed to handle safely. Also expressed as WLL (Working Load Limit). Exceeding SWL is illegal and potentially fatal.
UKCA Marking
UK Conformity Assessed marking — the UK equivalent of CE marking for products sold in Great Britain. Required for most PPE sold in England, Scotland, and Wales following Brexit.
MRO & Acronyms
18 termsBOM (Bill of Materials)
A comprehensive list of all components, parts, and assemblies required to build or maintain a piece of equipment. A critical document for planned maintenance and spare parts management.
CBM (Condition-Based Maintenance)
Maintenance triggered by equipment condition rather than time intervals. Sensors or inspections detect deterioration and trigger intervention only when needed — reducing unnecessary downtime and part changes.
CMMS (Computerised Maintenance Management System)
Software used to manage maintenance operations — scheduling PMs, tracking assets, managing spare parts inventory, and logging work orders. Examples include SAP PM, Maximo, and UpKeep.
Critical Spare
A component held in stock because its failure would cause significant production loss and lead times are too long to accept. Critical spare identification is a key part of maintenance strategy.
FMEA (Failure Mode and Effects Analysis)
A structured approach to identifying potential failure modes in equipment or processes, assessing their effects, and prioritising preventive actions. Common in RCM and new equipment commissioning.
IP Rating (Ingress Protection)
IEC 60529 standard classifying the degree of protection provided against solid particles and water. IP65 = fully dust-tight + protected against water jets. IP68 = dust-tight + continuous immersion.
KPI (Key Performance Indicator)
A measurable value used to evaluate success. In maintenance: OEE, MTBF, MTTR, and planned vs reactive maintenance ratio are common KPIs for tracking asset and team performance.
Lead Time
The time between placing an order and receiving goods. Critical for spare parts planning — long lead time items (e.g. custom bearings, specialist seals) must be held in local stock or sourced from a stocking distributor.
MRO (Maintenance, Repair & Operations)
The supplies, tools, and equipment used to maintain plant and facilities. Unlike raw materials, MRO items do not directly become part of the finished product — but their availability is critical to uptime.
MTBF (Mean Time Between Failures)
The average time a repairable asset operates between failures. A higher MTBF indicates greater reliability. Calculated as: total operating time ÷ number of failures.
MTTR (Mean Time To Repair)
The average time taken to restore a failed asset to operation. Includes diagnosis, parts sourcing, repair, and restart. Lower MTTR = higher uptime.
OEE (Overall Equipment Effectiveness)
A composite measure of manufacturing productivity: Availability × Performance × Quality. A "world class" OEE is generally considered 85%+. Used to identify and quantify production losses.
PM (Planned Maintenance)
Maintenance carried out at scheduled intervals regardless of equipment condition. Contrasted with reactive (breakdown) maintenance and CBM. PMs are defined by OEM recommendations and historical data.
RCM (Reliability-Centred Maintenance)
A systematic process for determining the most effective maintenance strategy for each asset based on its function, failure modes, and consequences. Originated in aviation, now widely used in industry.
RPN (Risk Priority Number)
In FMEA: Severity × Occurrence × Detectability (each scored 1–10). Higher RPN = higher priority for action. Used to rank failure modes and allocate preventive resource.
SKU (Stock Keeping Unit)
A unique identifier assigned to each distinct product in inventory. In industrial supply, SKUs track individual product variants — including size, rating, material, and specification.
TCO (Total Cost of Ownership)
The complete cost of acquiring, operating, and maintaining an asset over its lifetime — including purchase price, installation, energy, consumables, downtime, and disposal. A key metric for justifying better-quality components.
Uptime
The percentage of time an asset or production line is operational and producing. Target uptime is typically 95–99%+ in critical manufacturing. Uptime = 100% − Downtime%.
Tools
12 termsBearing Heater
An induction heating device that expands a bearing inner ring for easier mounting onto a shaft. Safer and more controlled than using an oil bath or blowtorch.
Bearing Puller
A tool designed to remove bearings from shafts or housings without damaging the shaft or surrounding components. Available in 2-jaw, 3-jaw, and hydraulic configurations.
Calibrated Torque Wrench
A precision wrench that measures and limits the applied torque to a specified value. Essential for bearing lock nuts, flange bolts, and any application requiring controlled tightening.
Dial Indicator
A precision measurement instrument with a clock-like display showing displacement in 0.01 mm or 0.001 inch increments. Used for shaft alignment, runout checking, and bearing installation verification.
Feeler Gauge
A set of thin metal strips of precisely known thickness used to measure small gaps and clearances. Common in bearing installation to verify internal clearance after mounting.
Grease Gun
A hand-held or pneumatic tool for delivering grease into bearing housings through grease nipples. Essential for bearing relubrication programmes.
Hydraulic Nut
A precision nut that uses hydraulic pressure to generate controlled axial force for mounting and dismounting large bearings. Replaces hammering or heating methods on heavy assemblies.
Laser Alignment Tool
Precision instrument projecting a laser beam onto a target to measure and correct shaft misalignment between coupled machines. Achieves accuracy within 0.01 mm — vital for bearing life.
Micrometer
A precision measuring tool capable of readings to 0.001 mm (1 micron). Used to verify bearing bore, shaft diameter, and housing dimensions before installation.
Pyrometer
A non-contact infrared thermometer for measuring surface temperatures. Used to monitor bearing housing temperatures during run-in and to detect abnormal heat build-up.
Ultrasonic Thickness Gauge
Non-destructive testing device measuring material thickness using ultrasound. Used to assess pipe wall and pump casing integrity without dismantling.
Vibration Meter
A handheld diagnostic tool measuring overall vibration velocity (mm/s RMS). Quick screening tool — trending readings over time identifies developing bearing or alignment faults.
Need Technical Advice?
Our engineers can help with product selection, specification, and troubleshooting — whether you know the part number or just the problem.
