The Bearing Specialists | Crawley, West Sussex
Manufacturing in the United Kingdom operates across two distinct standards worlds. Equipment designed and built in Britain or the United States frequently uses imperial dimensions. Equipment sourced from Germany, Italy, France, Switzerland, and increasingly from Asia runs to metric standards under DIN and ISO specifications. For engineers and maintenance teams responsible for facilities that contain both — which is the majority of UK manufacturing operations of any scale — the distinction between these two systems is not academic. It determines which bearing components will fit, which tolerances apply, how thermal expansion behaves across the system, and ultimately whether a machine runs reliably or generates costly unplanned downtime.
Make UK's 2025 Manufacturing: The Facts report places the UK at eleventh in global manufacturing rankings, with sector output valued at $279 billion and seven of the top ten export destinations in the EU. That European trade relationship is reflected directly in the equipment UK manufacturers run: German CNC machining centres, Italian packaging lines, Dutch material handling systems, and French automotive production equipment are commonplace across British factory floors. Each brings its own metric dimensioning, and the cam followers within those machines need to be specified and sourced accordingly.
This guide covers what metric cam followers are, how they differ from their imperial counterparts, the key design variants UK engineers encounter, and what to consider when specifying them for demanding industrial applications.
What a Cam Follower Actually Does
A cam follower is a specialised roller bearing mounted on a stud or yoke that follows the profile of a cam or track surface to convert rotary motion into controlled linear or oscillating movement. Unlike a conventional rolling element bearing that rotates around its own axis within a static housing, a cam follower rolls along an external surface — the cam profile or guide track — while supporting radial, axial, and in many applications combined loads simultaneously.
The outer ring of a cam follower is designed to be the bearing surface, hardened and ground to resist wear from repeated contact with the cam or track. The internal construction — full complement needle rollers, caged needle rollers, or cylindrical rollers depending on the design — provides the load-carrying capacity and speed capability required by the application. The stud or yoke mounting transmits the load to the machine structure.
This design makes cam followers essential wherever controlled motion guidance is required under load: conveyor guide systems, packaging machine infeed and outfeed mechanisms, CNC tool changers, cam-actuated indexing tables, printing registration systems, and material handling equipment of all kinds. They appear in enormous quantities across UK manufacturing — tens, hundreds, or thousands of units within a single production line — which makes correct specification and reliable sourcing critically important for operations that cannot afford extended downtime.
Metric vs. Imperial: Why the Distinction Matters for UK Operations
The practical difference between metric and imperial cam followers goes well beyond the nominal dimension on a datasheet. It extends into the tolerance system, the fit standards, and the thermal behaviour of the assembly in service.
Metric cam followers are dimensioned in millimetres and specified to ISO standards, with bore and outer diameter tolerances defined within the ISO fit system — typically H7 or H8 bore tolerances for the stud thread engagement and specific outer ring tolerances for the track or housing interface. Imperial cam followers use inch dimensions and are specified to AFBMA or ABEC standards with different tolerance bands. These two systems are not interchangeable. Substituting an imperial-dimensioned cam follower for a metric specification because the dimensions are numerically close — or using a metric-to-imperial conversion without accounting for the difference in tolerance classification — is a documented cause of installation failures in UK operations that run mixed-heritage equipment.
Thermal expansion adds another layer of complexity in mixed systems. European equipment is often designed to tighter running clearances than older British or American machinery. As temperatures rise in service — particularly in production environments where conveyors, ovens, and processing equipment generate sustained heat — the differential expansion between a metric shaft and an imperial bearing can shift an assembly from correct interference fit to loose running or, conversely, generate destructive preload. Getting the fit correct from the start requires understanding which standard applies, not estimating from approximate dimensions.
The UK's strong European trade connections mean this challenge is not going away. As UK manufacturers continue sourcing capital equipment from Continental Europe, the installed base of metric-dimensioned machinery grows. Engineers who understand how to specify metric cam followers correctly, and source them from suppliers with genuine expertise in ISO fit standards, maintain a significant advantage in keeping that equipment running reliably.
Key Design Variants: Stud Type and Yoke Type
Metric cam followers are available in two fundamental mounting configurations: stud type and yoke type. Each suits different installation geometries, and the choice between them is determined by the load direction and the machine structure at the mounting point.
Stud-type cam followers, designated in the metric series with the KR prefix (e.g., KR19, KR35, KR80), mount via a threaded stud that cantilevers the roller into contact with the cam or track. The stud projects from one side of the assembly, making this configuration simple to install and replace in applications where access is available from the mounting side. Stud-type designs are the most common metric cam follower configuration and appear across the widest range of applications, from light packaging machinery to heavy material handling.
Yoke-type cam followers, designated with the RNA or similar prefix in the metric series, mount via a yoke that straddles the cam follower and provides a two-point, straddle-mounted assembly. This configuration distributes the cantilever bending moment that the stud-type arrangement imposes, making yoke-type followers better suited to high radial loads and applications where moment loading would overstress a stud-type design. They require more complex installation geometry but deliver superior load capacity per unit of outer diameter.
The outer ring geometry also varies between designs. Standard cylindrical outer rings provide maximum contact area with flat tracks and are the default choice for linear guide applications. Crowned outer rings — slightly convex in the axial direction — compensate for angular misalignment between the cam follower axis and the track surface, distributing contact stress more evenly and preventing the edge loading that causes premature wear when alignment is less than perfect. In real industrial installations, where housing deflection, thermal growth, and assembly tolerances mean that perfect alignment is rarely achieved in service, crowned outer rings consistently extend service life.
Sealed vs. Open Construction and Lubrication Considerations
Metric cam followers are available with sealed and open construction. Sealed units arrive pre-lubricated and are designed to operate for extended periods without external lubrication, making them suitable for applications where access for re-greasing is difficult or where contamination makes open lubrication points a liability. Open construction cam followers accept grease through a nipple in the stud — many metric designs offer lubrication access through two ports, including the stud head — and are preferred where re-lubrication is part of a regular maintenance regime and service life requirements exceed what a sealed unit can deliver.
The choice between sealed and open construction should be made on the basis of the application's environmental conditions, access constraints, and expected service interval. In food processing or pharmaceutical environments where lubricant contamination is a compliance concern, sealed food-grade cam followers with appropriate FDA-approved grease fill eliminate the re-lubrication requirement entirely. In heavy industrial applications where cam followers run under sustained high loads, open construction with a structured re-lubrication programme will generally outperform sealed alternatives in total service life.
For a detailed examination of how these specification decisions affect long-term reliability — and what happens when they are made incorrectly — Metric Cam Follower Failures: The Root Causes UK Engineers Need to Eliminate covers the most common failure modes and how to avoid them.
Applications Across UK Industry
Metric cam followers appear across the full spectrum of UK manufacturing, but several sectors generate particularly significant demand because of the nature of their equipment and the performance requirements it places on these components.
CNC machining centres from German and Swiss manufacturers — Heidenhain-controlled machining centres, turning centres, grinding machines, and EDM equipment — rely on metric cam followers in tool change mechanisms, pallet changing systems, and axis guidance assemblies. The precision requirements in these applications are demanding: dimensional accuracy at the micron level, long service life under cyclic loading, and contamination resistance in environments where metalworking fluids are present throughout the machine.
Packaging equipment represents one of the largest application areas for metric cam followers in UK manufacturing. The UK's packaging automation market generated over £2 billion in 2024 and is expected to reach £3.7 billion by 2033, according to Automate UK (the trade association for UK automation, robotics, and packaging machinery). The conveyors, infeed mechanisms, cam-actuated forming sections, and registration systems within packaging lines depend on precisely specified metric cam followers running reliably at high cycle rates over extended production runs. An unexpected cam follower failure on a high-speed packaging line does not just stop one machine — it can halt an entire line and trigger downstream quality holds.
Material handling conveyors, both in manufacturing and distribution, represent another major application area where metric cam followers are specified in large quantities. European conveyor systems use metric dimensioning as standard, and the cam followers within them need to be sourced to the correct ISO specifications to deliver the service life the system was designed for.
For a detailed look at how these demands are playing out across UK packaging and conveyor operations — and what cam follower specifications those applications require — Why UK Packaging and Conveyor Systems Depend on Precision Metric Cam Followers explores the sector in depth.
Sourcing Metric Cam Followers in the UK: What to Expect from a Specialist
Standard metric cam follower sizes are available from catalogue stock, but the demands of UK industrial operations frequently extend beyond standard availability. Worn components from European equipment need to be cross-referenced accurately to current ISO metric series designations. Upgrades to sealed versions, crowned outer rings, or higher-specification materials may be required where standard versions have underperformed. Application conditions — unusual operating temperatures, corrosive atmospheres, pharmaceutical clean-room requirements — may demand non-standard options.
Sourcing metric cam followers from a specialist who understands ISO fit standards, DIN specifications, and the specific requirements of European industrial equipment produces consistently better outcomes than sourcing from a catalogue distributor optimised for standard transactions. The Bearing Specialists supply metric cam followers to operations across the UK from stock, with technical guidance covering tolerance selection, material specification, and the application-specific requirements that determine whether a cam follower delivers full service life or fails prematurely.
The Bearing Specialists: Metric Cam Follower Expertise for UK Industry
The Bearing Specialists are ISO 9001:2015 certified bearing specialists based in Crawley, West Sussex. Our team has supplied metric cam followers to manufacturers across the UK for years, with expertise covering ISO and DIN standards, European equipment specifications, and demanding applications in automation, packaging, material handling, and precision machining.
Our Services Include:
- Metric Cam Followers — Stud type, yoke type, cylindrical and crowned outer rings, sealed and open construction across the full metric size range for UK industrial applications
- Technical specification support — Tolerance selection, material options, cross-referencing from European equipment designations, and application guidance for demanding operating conditions
Ready to Specify the Right Components? Contact The Bearing Specialists on +44 (0)1280 460116 or email Sales@thebearingspecialists.co.uk to discuss your metric cam follower requirements.
Works Cited
"UK Manufacturing: The Facts 2025." Make UK, Sept. 2025, www.makeuk.org/insights/reports/uk-manufacturing-facts-2025. Accessed 26 Mar. 2026.
"Industry Insights 2024–2025." Automate UK, www.automate-uk.com/industry-insights-2024-2025/. Accessed 26 Mar. 2026.
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- Why UK Packaging and Conveyor Systems Depend on Precision Metric Cam Followers
- Metric Cam Follower Failures: The Root Causes UK Engineers Need to Eliminate