When a centreless grinding operation starts producing out-of-specification parts, the investigation rarely starts with the formers. Operators check wheel condition, inspect the work-rest blade, and review the coolant. The former - the tooling that governs component profile and movement through the machine - is often left until last. This is a costly oversight.

Formers, cams and cam followers are central to consistent centreless grinding performance, particularly in operations where profiled or stepped components are being ground. When these components wear, the consequences are measurable: inconsistent part profiles, increased scrap rates and production losses that compound over time.

What Formers and Cams Actually Do

In centreless grinding, formers and cams work in combination to control the movement and positioning of the workpiece at key points during the grinding cycle. Depending on the machine type and application, they govern how a component is guided, supported or fed, allowing the grinding wheel to remove material in a controlled, repeatable way.

This is particularly critical for components that are not simple cylinders - parts with tapers, profiles or stepped diameters that require the grinding action to follow a defined path rather than operate on a uniform surface. In these applications, the former is not a secondary component. It is directly responsible for the accuracy of the finished part profile.

Cam followers - the rolling or sliding elements that track the cam surface - transmit that motion. If either the cam or the follower wears, the motion transmitted to the workpiece deviates from the intended path. The machine does not know this has happened. It continues grinding, but no longer grinding the correct profile.

How Wear Develops and Why It Goes Unnoticed

Former and cam wear tends to develop gradually. Unlike a grinding wheel that becomes visibly glazed or a work-rest blade that shows obvious signs of regrinding being needed, cam and former wear is often subtle - a few microns of surface degradation that accumulates over weeks or months of production.

Because the change is incremental, it rarely triggers an immediate quality alarm. Instead, it shows up as a slow drift in part dimensions, a gradual increase in out-of-tolerance rejects, or a creeping inconsistency in part profiles that operators attribute to other causes. By the time the former is identified as the problem, significant scrap has already been produced.

Signs worth investigating as potential indicators of former and cam wear include:

• Progressive profile deviation across a production run - Parts that pass inspection at the start of a batch but drift out of tolerance as the run continues suggest a wear-related issue rather than a setup problem.
• Inconsistency between identical parts - If nominally identical components are grinding to slightly different profiles, the tooling controlling their movement through the machine should be examined.
• Increased surface chatter on profiled sections - Chatter on specific areas of a component profile, rather than uniformly across the surface, can indicate that the former is no longer guiding the workpiece smoothly through that section of the cycle.
• Difficulty achieving repeatable setup - If the machine requires frequent readjustment to hold profile tolerances that were previously stable, worn formers are a likely contributor.

The Case for Refurbishment Over Replacement

New formers and cams, particularly those machined to precise profiles for specific components or machine configurations, represent a significant cost. The instinct when tooling becomes problematic is often to replace it. In many cases, however, refurbishment is a more practical and cost-effective route.

Workblades & Formers Ltd runs a dedicated regrinding and refurbishment service that covers formers, cams and cam followers. Worn surfaces are reground to restore original geometry, contact surfaces are brought back within tolerance, and the refurbished tooling is returned ready for service - at a fraction of the cost of new manufacture.

The key requirement for successful refurbishment is not waiting too long. A former that has worn moderately can be reground cleanly and returned to accurate working condition. One that has been allowed to wear severely, or that has been operated with contamination or impact damage, may have exceeded the recoverable material allowance. Scheduling refurbishment as a planned activity - rather than reacting to a quality failure - gives the best outcomes and the best economics.

Custom Manufacture for Non-Standard Applications

Not every former or cam is available off the shelf. Machines that have been in service for many years, machines running unusual component profiles, or operations that have evolved since original machine specification may require tooling that no longer exists as a standard catalogue item.

Workblades & Formers designs and manufactures formers, cams and cam followers to customer specification or reverse-engineered from worn parts. This means that even where original drawings no longer exist, tooling can be accurately reproduced from a physical sample - extending the productive life of machines that might otherwise be difficult to support.

This capability is particularly relevant for businesses running older centreless grinders from brands such as Cincinnati, Ghiringhelli, BSA, Tschudin, Wickman Scrivener or Lidköping, where original spare parts supply may be limited or unavailable.

Integrating Former Condition Into Your Maintenance Approach

The most effective way to manage former and cam wear is to include these components in a planned maintenance and inspection schedule, rather than treating them as items that only need attention when a quality problem occurs.

Practical steps include:

• Establishing a baseline inspection interval for formers and cams based on production volume and material being ground.
• Keeping dimensional records of former condition over time, so that wear progression can be tracked and refurbishment scheduled before quality impact occurs.
• Maintaining a spare set of refurbished formers where the production application justifies it, allowing rapid changeover if tooling needs to be taken out of service.

Workblades & Formers supports customers across the UK and Europe with exactly this kind of structured approach - combining tooling supply, regrinding services and technical guidance to keep centreless grinding operations productive and under control.

Getting Support

If you are seeing profile inconsistency, increasing scrap or difficulty holding tolerances on profiled components, and the obvious causes have already been investigated, it is worth having your formers and cams examined. Workblades & Formers Ltd can assess worn tooling, advise on refurbishment options and manufacture replacement parts where required.

Get in touch with the team at workblades.co.uk to discuss your application.