The Patek Philippe Calatrava is one of the most recognizable classic dress watches in fine watchmaking. Its understated dial, elegant proportions and sophisticated mechanical construction have made it a long-standing favorite among collectors.

Even so, a high-end mechanical watch can gradually develop timekeeping issues after years of use.

In this repair case, a Calatrava began showing noticeable changes in its daily rate. The watch was still running, but its accuracy had clearly declined compared with its previous performance. It was therefore sent to a professional watch service centre for a complete inspection.

(Actual repair case. Images are for illustrative purposes only.)

Basic Details of the Repair Case

The owner reported several changes during regular use:

The watch had gradually begun running slow
Daily rate deviation had become more noticeable
Power reserve had decreased
The movement had not received professional servicing for an extended period

The exterior of the watch remained in good condition, with no obvious signs of impact.

However, an undamaged case does not necessarily mean that the movement is operating perfectly. Internal components continue to experience friction and mechanical stress during years of operation.

Initial Timing Performance Test

Before opening the watch, the watchmaker first tested the movement using professional timing equipment.

The inspection focused on:

Daily rate
Balance amplitude
Beat error
Positional variation
Performance as the mainspring unwinds

The results showed that the movement's timing stability had declined.

The balance amplitude was also lower than expected, suggesting that the issue could involve energy transmission and increased friction rather than simply a regulation problem.

Movement Removal and Component Inspection

After the initial testing, the movement was carefully removed from the case.

A professional service does not begin by immediately replacing parts.

Instead, the movement is progressively disassembled so that each major component can be examined.

The inspection included:

Mainspring barrel
Gear train
Balance and hairspring
Escapement
Jewel bearings
Winding system

With a fine mechanical movement, even a small increase in friction can affect the efficiency of the entire system.

Identifying the Problem: Deteriorated Lubrication

After disassembly, the watchmaker found that the lubrication condition of several movement components had deteriorated.

Lubricants inside a mechanical watch do not remain at peak performance indefinitely.

After years of operation, lubrication can lose its effectiveness, increasing friction between moving components.

This can contribute to:

Reduced balance amplitude
Lower energy efficiency
Less stable timekeeping
Increased mechanical wear

For this reason, the repair was not limited to adjusting the rate. A complete movement service was considered necessary.

Movement Cleaning and Component Treatment

Once the movement had been completely disassembled, the components were professionally cleaned.

The purpose of cleaning is not simply to remove visible dust.

It also helps eliminate aged lubricants and microscopic contaminants accumulated during prolonged operation.

Each component is inspected individually.

If significant wear is discovered, the watchmaker must determine whether the part should be restored or replaced.

For a high-value mechanical watch, unnecessary replacement should be avoided whenever possible, while worn components that could compromise reliability should be addressed appropriately.

Relubrication and Movement Assembly

After cleaning and inspection, the movement was carefully reassembled.

Different components require different lubrication methods.

Gear pivots, jewel bearings and other moving parts must receive the appropriate lubricant in the appropriate quantity.

Too much lubricant can cause unwanted migration, while insufficient lubrication can increase friction.

Correct lubrication is therefore one of the most technically important stages of mechanical watch servicing.

Fine Regulation and Timing Adjustment

Reassembly does not mean that the service is finished.

The movement must be tested again and carefully regulated according to the measured results.

The watchmaker evaluates:

Rate
Balance amplitude
Beat error
Positional performance
Stability as the power reserve decreases

Multiple tests may be required before the movement reaches a stable operating condition.

Only after the timing performance has been properly evaluated can the movement proceed to final casing and inspection.

The Result After Servicing

Following the complete movement service and regulation, the Calatrava showed improved timing stability.

The previously noticeable deviation became more consistent, while the winding feel and general operation of the movement also improved.

This case demonstrates an important point about mechanical watches:

A watch can still be running without necessarily being in optimal mechanical condition.

Before a movement develops a serious fault, there may already be signs of deteriorating lubrication, increased friction or component wear.

Early professional inspection can help identify these changes before they become more complicated problems.

Why Professional Watch Servicing Requires More Than Simple Adjustment

The value of a high-end mechanical watch is not limited to its exterior appearance.

Much of its craftsmanship is hidden inside the case.

When a watch begins to run noticeably faster or slower, develops unusual winding resistance or shows a decline in power reserve, the real priority should be identifying the underlying cause.

Professional servicing involves timing measurements, movement disassembly, component inspection, cleaning, lubrication, reassembly and regulation.

Simply adjusting the rate without understanding the reason for the change may not address the underlying mechanical issue.

For valuable watches, a careful and methodical approach can help preserve the condition of the movement and maintain reliable long-term performance.

Professional Watch Service

Professional watch servicing requires specialized equipment, technical expertise, and years of experience. Every luxury mechanical watch deserves careful inspection and precision maintenance by qualified watchmakers.