In most centreless grinding operations, the investigation into quality problems follows a familiar sequence. The grinding wheel is dressed. The work-rest blade is inspected. The control wheel is checked for glazing. The coolant is reviewed. Rarely does the investigation reach the cams and cam followers — the components that govern how the workpiece is presented to the grinding zone in infeed and angular infeed operations.

Yet worn or incorrectly set cams and cam followers are a consistent source of dimensional inconsistency in centreless grinding, particularly on high-volume lines where those components accumulate wear over thousands of cycles. Understanding what they do, how they wear, and what that wear costs you in production terms is a practical first step towards protecting process consistency.

What Cams and Cam Followers Do

In infeed centreless grinding, the workpiece is not fed axially through the machine. Instead, it is loaded into the grinding zone and the grinding wheel is fed in radially to remove stock to a defined diameter. The mechanism controlling that radial infeed — the depth to which the wheel advances and the rate at which it does so — is governed by the cam profile.

The cam follower rides against the cam surface and translates its profile into controlled machine movement. A well-maintained cam and follower delivers repeatable, predictable infeed behaviour cycle after cycle. A worn cam or follower does not. The result is dimensional scatter — parts that measure differently from one cycle to the next, even when everything else in the process appears unchanged.

This is why cam and cam follower condition matters. It is not a background detail. It is directly connected to the dimensional output of your machine.

How Wear Presents in Production

Cam and cam follower wear tends to be gradual, which is part of what makes it difficult to identify. Production does not suddenly degrade. Instead, it drifts slowly, and the signs are easy to attribute to other causes.

The following are worth investigating as potential indicators of cam and cam follower wear:

• Diameter scatter within a batch - Parts measuring consistently on Monday morning but showing increasing variation by the end of the week, with no change to wheel specification or setup, is a pattern associated with progressive cam wear rather than abrasive or coolant issues.
• Inconsistent cycle time - If the infeed stroke is taking varying amounts of time across a production run, the cam follower is not tracking the cam profile consistently. This suggests wear on the follower contact face or on the cam surface itself.
• Random oversize or undersize parts within an otherwise stable run - Occasional outliers, rather than a general trend, can indicate a follower that is intermittently losing proper contact with the cam surface, particularly at the beginning or end of the infeed stroke.
• Audible noise during the infeed cycle - Clicking, light knocking or irregular mechanical sound during the cam-driven infeed phase often indicates that clearance has developed between the follower and cam due to wear.

The Cost of Running Worn Cam Components

The immediate cost of worn cams and cam followers is scrap. Parts produced outside tolerance represent direct material and labour cost. On high-value components - such as medical device parts or aerospace components where raw material cost is significant - those scrap losses accumulate quickly.

The less visible cost is the time spent elsewhere in the process compensating for dimensional instability. Adjusting wheel offsets, making blade corrections, or tightening inspection intervals to catch out-of-tolerance parts are all indirect costs generated by the cam system failing to deliver repeatable infeed behaviour. They do not appear on a maintenance report, but they are real costs with real consequences for output efficiency.

There is also a machine wear consideration. A cam follower that is no longer tracking cleanly can introduce irregular loading into the infeed mechanism, accelerating wear on adjacent components. Addressing cam and follower condition early, before wear progresses to secondary components, is the lower-cost approach.

Refurbishment vs. Replacement

Not every worn cam or cam follower needs to be replaced outright. Where the cam profile has worn rather than damaged, refurbishment to restore the original geometry is often a practical and cost-effective option. Workblades & Formers designs, manufactures and refurbishes cams and cam followers in-house, including reverse-engineered components for older or less common machine models where standard replacement parts are no longer readily available.

This matters particularly for manufacturers running older centreless machines from brands such as Cincinnati, BSA, Tschudin, Wickman Scrivener or Ghiringhelli, where sourcing original cam components through the original equipment manufacturer is no longer straightforward. The ability to reverse-engineer and reproduce worn parts to original geometry means that machine age is not a barrier to restoring cam system performance.

Where components are beyond refurbishment, new manufacture to drawing or to the worn part as a reference is the alternative. Either way, the outcome is a cam system that delivers the repeatable infeed behaviour the process depends on.

Integrating Cam Inspection into Maintenance Routines

Because cam and cam follower wear is gradual, it benefits most from being built into a scheduled inspection routine rather than being assessed reactively after quality problems emerge. Checking follower contact faces for wear flats, checking cam surfaces for scoring or profile deformation, and measuring follower-to-cam clearance at defined service intervals gives production teams early warning before wear reaches a level that affects output.

Workblades & Formers supports customers across the UK and Europe with centreless machine servicing, technical troubleshooting and tooling supply. If your centreless grinding process is showing signs of dimensional inconsistency that other investigations have not resolved, the cam and cam follower system is a logical next area to examine.

Contact the team in Birmingham to discuss inspection, refurbishment or replacement of cam components for your machine.