Industrial chain glossary - Chain Hub

Industrial chain glossary


Adapted conveyor chain

Adapted conveyor chain is conveyor chain that has been fitted with attachment plates. Attachments can be fitted on one or both sides of the conveyor chain at any required pitch spacing. Bearing pins with an extension are an easy way of fastening attachments or tubular stay bars to the chain.

AL series

AL stands for American Light and is a type of leaf chain constructed from American Standard roller chain components. Manufactured to the ANSI B29.9 standard, it is a lightweight chain used for light load lifting applications and machine tools.


When a chain travels around a sprocket it articulates or rotates. The ‘angle of articulation’ or ‘angle of flex’ is the angle that a joint rotates as it enters or leaves a sprocket. This angle can be calculated by dividing 360 by the number of teeth on the sprocket.


ANSI stands for the American National Standards Institute which exists to set and promote international manufacturing standards.


Bedding in

Bedding in is where a chain experiences a high degree of wear at the start of its service life. After this initial phase, the chain wears at a steady rate.


BITA stands for British Industrial Truck Association and is an organisation that provides support and information for forklift truck and forklift truck component manufacturers and suppliers. BITA is also involved in setting technical standards for the industry.


A bush is a tubular metal sleeve or lining fitted to the inner link of a chain to serve as a bearing or guide.


BS stands for British Standards Institute which exists to set and promote international manufacturing standards.

BL series (also known as LH series)

BL series is a type of leaf chain manufactured according to ISO4347, DIN8152, ANSI B29.8 and NFE26107. BL (LH) series leaf chain is the only leaf chain that is constructed from specific leaf chain components. It is a heavy duty chain used for forklift trucks, lifting and materials handling equipment.

Bottom diameter (also known as root diameter)

The bottom diameter of a sprocket is the lowest point of a tooth. It is equal to the pitch circle diameter minus the chain roller diameter.

Breaking load (also known as tensile strength, ultimate tensile strength or UTS)

The breaking load is the load at which a chain will break. It is not intended to be a working load and is used merely as comparison of the relative strength of different chains.


Case hardening (also known as surface hardening)

Case hardening is the process of hardening the surface of a metal by infusing elements into the material’s surface, forming a thin layer of a harder alloy. It is used to extend the wear life of chains components and attachments.

Chain wear gauge

A chain wear gauge is a device used to measure chain elongation. Basic chain wear gauges of the ‘worn or not worn’ variety are typically made from steel or tape. Because chains must be replaced once they have reached 3% elongation, a steady hand and arithmetical calculation are required. ‘How much worn’ gauges such as the FB Professional Chain Wear Gauge feature a slider and show the percentage elongation in a window on the gauge itself.

Chain tensioner (also known as a chain take-up)

A chain tenisoner is a device such as an idler sprocket or spring loaded guide which compensates for slackness due to chain wear and is used to limit unnecessary downtime.

Chordal effect (also known as polygonal effect)

The chordal effect occurs when a chain forms a polygon rather than a smooth curve around a sprocket. It often occurs in chain drives with a low tooth count in the smallest sprocket and leads to noticeable speed variations in the movement of the chain.

Closed U flight

A closed U flight is a type of attachment fitted to drop-forged conveyor chains. It can be used on inclines up to 60° and is frequently used for the en-masse conveying of grain, feed and woodchip.

Conveyor chain

Conveyor chain is industrial chain that has been designed specifically for chain conveyor systems. It consists of a series of journal bearings that are held together by constraining link plates. Each bearing consists of a pin and a bush on which the chain roller revolves.

Cotter pin

A cotter pin is a small device that is inserted into a cross hole at the end of a pin to provide extra security in the chain structure.

Chain elongation (also known as chain stretch)

As a chain wears, the pins no longer sit tightly in the plate holes and the length of the chain increases. This increase is typically measured using a chain wear gauge and given as a percentage of the nominal length.

Compressive stress

Compressive stress is applied locally using techniques such as shot peening to increase the fatigue resistance.

Chain width (also known as inside width)

The chain width is the distance between the two inner plates. To allow smooth engagement, this dimension is greater than the width of the sprocket teeth.

CS2 conveyor chain tensioner

The CS2 conveyor chain tensioner is an automatic chain tensioner to be used with chain conveyor systems. It works independently to keep the chain taut with a constant optimum pressure.



DIN stands for Deutsche Institut für Normung and is a body responsible for setting manufacturing standards in Germany.

Double pitch chain (also known as extended pitch chain)

Double pitch chain is a type of conveyor chain that uses the round parts from standard chain but has twice the pitch. It is a lightweight conveyor chain used on drives with long centre distances.

Deep link conveyor chain

Deep link conveyor chain has deeper side plates than the normal chain plates and so provides a continuous carrying edge above the roller periphery. Deep link chain comes in solid and hollow bearing pin varieties.

Double pitch sprocket

A double pitch sprocket has twice the number of teeth as a standard sprocket of the same pitch circle diameter. Only every other tooth is engaged in each rotation, meaning that wear is distributed more evenly and the service life is increased.

Drop forged conveyor chain (also known as drop forged scraper chain)

Drop forged conveyor chain is a type of chain for chain conveyors that is almost always fitted with flights or special attachments. The chain links themselves are forged from specially selected alloy steel and then precision machined to close tolerances. Drop forged conveyor chains are widely used in bulk materials handling of products such as grain, coal and ash.

Duplex chain (also known as double strand chain)

Duplex chain consists of two stands of chain joined by a common pin at every pitch.

Dynamic impulse (also known as shock loading)

Dynamic impulse occurs when a chain supports a load that is above the fatigue endurance limit and can lead to fatigue failure.


EL series (also known as LL series)

EL stands for European Light (or Leaf Light) and is a type of leaf chain constructed from European Standard roller chain components. Manufactured to ISO4347, DIN8152 and NFE26107, it is a lightweight chain used for light load lifting applications and machine tools.

Elastic limit

The elastic limit of a chain is the maximum load it can support without experiencing permanent change in length. The elastic limit is usually around 70% of the breaking load.

En-masse conveying

En-masse conveying involves inducing material to behave almost as a liquid by exerting a motive force along the entire conveying length.

Extended bearing pin attachment

An extended bearing pin attachment is a type of conveyor chain attachment that consists of a chain pin that extends beyond the length of the riveted pins to carry end used fittings.


Embrittlement occurs when the ductility of a material has been reduced and can lead to premature failure. It is often due to incorrect material selection or heat treatments. Hydrogen embrittlement is caused by the presence of hydrogen sulphide, hydrochloric acid or sulphuric acid which are sometimes present in batteries or cleaning fluids. Electroplating, welding and pickling are common causes of hydrogen embrittlement.

Endurance (also known as fatigue resistance or fatigue strength)

Fatigue occurs when a chain is repeatedly loaded. If the chain is subject to a high level of stress, it will fail after only a few circles. If the stress is reduced, the number of cycles before failure increases until the point at which failure will never occur. The chain is now operating below the ‘endurance limit’. If stress is controlled, failure will most likely be due to wear rather than fatigue.



FB stands for Fabriks Bolaget, Swedish for ‘plant company’. The FB Group originated as a single business, Eskilstuna Fabriks Bolaget, founded in Eskilstuna, Sweden in the 1870s. In their wisdom the original management shorted the name to FB.

FB Chain Ltd.

FB Chain Ltd. is the UK arm of the FB Group, based in Letchworth, Hertfordshire.

FB Group

FB Group is a network of six autonomous industrial chain manufacturers and suppliers across Europe owned by Swedish Addtech AB. As each FB subsidiary focuses on a particular niche product, the group as a whole is able to offer customers highly specialised chain and associated parts for a wide range of different industries and applications. Customers are able to order their required chain (including leaf chain, conveyor chain, roller chain, sawmill or sharp top chain) from their local FB branch which will then be shipped from the factory where it is produced.

FB Kedjor AB

FB Kedjor AB is the Swedish arm of the FB Group, based in Eskilstuna.

FB Kjeder AS

FB Kjeder AS is the Norwegian arm of the FB Group, based in Oslo.

Flanged roller

A flanged roller is a roller used for conveyor chain. The diameter of the roller is greater than that height of the inner plates which allows the chain to run along and above a horizontal surface. The flanges act as a guide.

Flat bar flight

A flat bar flight is a type of attachment fitted to drop-forged conveyor chain. It can be used on inclined conveyors up to 20° for en-masse or drag conveying.


FLTA stands for Fork Lift Truck Association and is an independent body that represents manufacturers, importers, distributors, dealers and suppliers of ancillary equipment and services. It exists to maintain and raise standards in the materials handling industry.

FB Ketjutekniikka Oy

FB Ketjutekniikka Oy is the Finnish arm of the FB Group, based in Köyliö.

FB Ketten GmbH

FB Ketten GmbH is the German arm of the FB Group, based in Eslohe.

FB Ketten Handelsgesellschaft m.b.H

FB Ketten Handelsgesellschaft m.b.H is the Austrian arm of the FB Group, based in Kufstein.


Galling (also known as scuffing or seizing)

Galling is damaged caused by solid-phase welding between sliding surfaces without local melting. It usually occurs between a pin and a bush where the load is too great or there is insufficient lubrication.


Henry II

Henry II is a press mount assembly tool for installing conveyor chain.



ISO stands for the International Organisation for Standardisation. ISO is a non-governmental organization comprising the national standards institutes of 147 countries with a Central Secretariat in Geneva, Switzerland. ISO standards are produced by a committee consisting of representatives from chain manufacturers, industry and institutions from all over the world.

Induction hardening

Induction hardening is a type of heat treatment that hardens the steel by alternating a magnetic field to a temperature above or within a specific transformation range before quenching. Induction hardening increases wear resistance and service life.

Inner link

The inner link of a chain consists of two inner plates joined by two press fit bushes.

Inno scrapers (also known as Inno flights)

Inno scrapers are a conveyor chain attachment used to push the materials or goods conveyed along the chain conveyor system. Inno scrapers differ from standard conveyor scrapers in that they are made from multi-laminated beech rather than steel. In case of overloading, Inno scrapers snap, limiting damage to surrounding equipment and can be quickly and easily replaced. Being made from wood, Inno scrapers can also be disposed of using chipping units and furnaces.



Leaf chain (also known as forklift truck chain, FLT chain, lifting chain)

Leaf chain is a type of industrial chain consisting of interleaved plates joined by riveted pins. It is typically used in forklift trucks and for other lifting applications.


LOLER is short for Lifting Operations and Lifting Equipment Regulations 1998. LOLER covers leaf chains, slings and eyebolts as well as the equipment that uses them e.g. forklift trucks, cranes, mobile elevated platforms and vehicle inspection platform hoists. LOLER requires that lifting apparatus is strong and stable enough for the particular use and marked to indicate safe working loads; positioned and installed to minimise any risks; used safely, i.e. the work is planned, organised and performed by competent people; and subject to ongoing thorough examination and, where appropriate, inspection by competent people. Lifting equipment is also subject to PUWER regulations.


Lacing refers to leaf chain plate structure. The diagram above illustrates a 2×3 lacing. This means that it consists of 2 outer plates and 3 inner plates.

Loose fit

Loose fit is when a plate has no press fit with the corresponding outer plate.


Maximum working load

The maximum working load is the maximum load a chain can support before it will experience fatigue failure. The maximum working load is determined by carrying out fatigue tests in laboratory conditions but can be lower at certain speeds and temperatures and should be discussed with the manufacturer.

Measuring load

The measuring load is a proof load that should be applied when measuring chain elongation with a chain wear gauge. It is usually 1% of the chain tensile strength.

Multiplex chain (also known as multi-strand chain)

Multiplex chain consists of several strands of chain joined together by a common pin at every pitch.



OEM kit

FB Chain provides OEMs (original equipment manufacturers) with leaf chain, anchor bolts, pins and pulleys pre-assembled or in ready to assemble OEM kits.

OO flight

An OO U flight is a type of attachment fitted to drop-forged conveyor chains. It can be used on inclines up to 90° and is frequently used for the en-masse conveying of grain, feed and woodchip.


Paddle flight

A paddle flight is a type of attachment fitted to drop-forged conveyor chains. It is frequently used for drag conveying cement, wood chips, coal and aggregates.


The pitch of a chain is the average distance between pins.

Pitch circle diameter (also known as PCD)

The pitch circle diameter is an imaginary circle running through the centres of the chain rollers of a chain when engaged on the sprocket.


A plate is a chain component. Plates are typically paired, two on an inner link and two on an outer link.

Pulley (also known as sheave)

A pulley is a tubular component with flanges used to guide a leaf chain during lifting operations.

Parallax error

Parallax error is error in reading an instrument employing a scale and pointer because the observer’s eye and pointer are not in a line perpendicular to the plane of the scale. It is a common problem with steel rule or tape chain wear gauges.

Preloading (also known as proof loading or pre-stretching)

Preloading is when the manufactured applies a load to a finish chain to check its integrity and bed in components. This load is usually a minimum of 30% of the breaking load.

Press fit (also known as interference fit)

Press fit is the difference between the diameter of the round component (pin or bush) and the plate hole into which it is inserted.


PUWER is short for Provision and Use of Work Equipment Regulations 1998. PUWER covers any equipment used by an employee at work. Lifting equipment is also subject to the requirements of LOLER.



Return cup flight

A return cup flight is a type of attachment fitted to drop-forged conveyor chain. Return cup flights are used on an intermediate basis with standard flat bar flights to carry back up any product that may cause build up inside a conveyor.

Roller (also known as thimble)

A roller is part of the inner link and guides the chain as it rotates on the bush.


Sharp top chain (also known as toothed chain or sawmill chain)

Sharp top chain is a type of chain used for conveying purposes in the timber and pulp industries.

Small pitch chain (also miniature chain)

Small pitch chain (4mm-8mm pitch) is transmission chain to be used for light applications.

Square bar flight

A square bar flight is a type of attachment fitted to drop forged conveyor chain. It is typically used for en-masse conveying in the grain and feed industries.

SuperEndurance chain (also known as SE chain)

SuperEndurance chain is a type of leaf chain that features tightened press fit between the pin and side plates. This increases the fatigue resistance. It is intended for especially high load applications such as container handling at ports and docks.

Shear pin sprocket

A shear pin sprocket features a pin that snaps when overloaded and breaks the connecting between the drive and the chain, bringing the conveyor to a halt. The aim is to limit damage to the goods, conveyor and surrounding equipment.

Shot peening

Shot peening is a manufacturing process that applies compressive stress to components to improve fatigue life.

Split sprocket

A split sprocket is formed of two halves and is used for multi-strand conveyors with long ‘through shafts’.


A sprocket is used to transmit force from the driving shaft to the chain.

SuperShield chain

SuperShield chain is a type of leaf chain applied with a GEOMET® coating for extra corrosion resistance. It is intended for lifting equipment operating outdoors or in moist environments or for equipment that frequently needs to be washed down.


Torque limiter (also known as overload clutch)

A torque limiter is an automatic device that protects chain conveyors from damage due to crash stops and jams. It may be in the form of a shaft coupling or a hub for a sprocket and acts by slipping (as in a friction plate slip-clutch) or uncoupling the load entirely.

Test certificate

Each chain should be issued with a test certificate which demonstrates that the chain has been subject to certain quality and safety tests. Test certificates should detail the batch number, order number, minimum breaking load and proof load applied.


Torque is a standard engineering term which expresses the function of force times distance. In the case of a chain drive, the torque is equivalent to the chain pull multiplied by half the sprocket pitch circle diameter. Torque is measured in Newton metres (Nm).


U flight

A U flight is a type of attachment fitted to drop-forged conveyor chains. It can be used on inclines up to 30° and is frequently used for the en-masse conveying of grain, feed and woodchip.



Zinc plating

Zinc plating is a type of plating that provides extra corrosion protection.

View all articles