Bonfield

Before your watch is being serviced, our highly skilled Bonfield-trained watchmakers will conduct a thorough diagnostic examination of the watch to determine the exact servicing procedures that are required to restore the watch back to its original high performance standard.

MOVEMENT MAINTENANCE SERVICE

Microscopic examination

"Platax" Tool - Removing roller and balance staff

Staking Tool - Replace balance staff

Seitz Jewelling Tool - Micrometer adjustment of set jewel permitting correction of endshake

Our watchmaker begins the service process by completely disassembling the watch movement. Each precise part is carefully examined under a 10x magnifying microscope for wear & tear or damage, and will be replaced or refurbished if deemed necessary.

Dried oils / contaminants are then removed from all parts by a series of ultrasonic cleaning processes.

Felting - To eliminate scratches with abrasive paste

Polishing of the back case

Sandblasting of the case

Lapping - The bevels are reground and polished

Your watch casing is carefully disassembled and all gaskets / o-rings are replaced. If necessary, the crystal, crown and any worn parts will also be replaced to ensure that the watch remains completely waterproof.

The watch case and bracelet are put through an ultrasonic cleaning process to remove particles that can oxidise the case and bracelet.

The case and bracelet are then meticulously refinished. Techniques of bevelling, lapping, polishing, brushing, sandblasting and circular-graining to remove dents and scratches are employed so as to restore the case and bracelet to its original lustre.

Reassembling of the watch movement

Lubricating the movement - Each pivot of the watch train wheels and balance staff are lubricated with recommended high grade lubricants

Our watchmaker will proceed to reassemble the movement; an operation which requires extreme dedication as it is both a highly delicate and time-consuming task. This step has to be conducted with painstaking care. Specially formulated oils and lubricants are applied in exactly the right quantities to achieve optimal performance of the movement.

Timing calibrations - Balance wheels are meticulously timed

Witschi "Watch Expert" - Measures the rate accuracy, amplitude and the beat error of mechanical watches

Wrist Motion Simulator - Testing the winding mechanism and the power reserve of automatic watches

Demagnetisation

After re-assembly, the movement is carefully calibrated by adjusting the balance wheel, which is also the "heart of the movement", and the hairspring which oscillates it. The performance and daily accuracy of the movement are then tested in required positions on a sophisticated timing machine to ensure that they are set to the required high-performance standards.

Finally, the dial, hands and rotor self-winding mechanism are fitted back in their positions, and the movement is returned to the case. The newly assembled watch will undergo 5 continuous days of testing, on a wrist-motion simulator, which recreates the normal activities that the watch may encounter when worn on your wrist.

Pressure Testing - Waterproof watches are pressure tested to 330 feet

The watch will now undergo a final pressure test in a special vacuum tank. This ensures that the waterproof qualities of the watch are retained in accordance with stringent factory criteria.

Final Inspection will be the most stringent check point conducted by the trained eye and sight of the Bonfield's watchmaker

The final step will see the watch passing the final, systematic and uncompromising meticulous inspection by the watchmaker. Our watchmakers from Bonfield are reputed to be the finest in the industry due to their years of practice, expertise and dedication. When you send your watch to Bonfield, you are assured of uncompromising service and absolute dedication. You can be certain that your watch has been treated with utmost respect, and has been paid the absolute attention to detail.

Bonfield is equipped with a comprehensive array of the finest Swiss equipment, affording us a distinctive advantage and unparalleled capabilities in the meticulous restoration of both vintage and pocket watches. Our commitment to restoring your cherished and sentimental timepieces is underscored by our dedication to returning them to their original standards of excellence.

Recognising that the restoration of these exceptional vintage pieces demands an investment of time and attention far beyond routine maintenance, Bonfield distinguishes itself by crafting bespoke, hand-made parts for components that are either challenging to procure or no longer available. Our artisans expertly repair and polish steel surfaces, corners of bridges, cocks, and screws, ensuring the comprehensive rejuvenation of your timepieces.

The rarity and specialisation of this skill are underscored by the extraordinary dedication to education and training required. Such artisanal expertise is a distinction held by only a select and exclusive group of watchmakers globally. At Bonfield, we take pride in being part of this distinguished cohort, ensuring that our craftsmanship reflects the pinnacle of precision and artistry in watch restoration.

Turing Caliber - Inspect the flatness of balance wheel

Poising Tool - To ensure that the balance wheel is poised or balanced

Reducing the weight of the balance wheel

The "Jacot" Pivot Lathe - is used for burnishing pivots of the watch train wheel

Fabrication of precision parts with the aid of the watchmaker's lathe

To forge the guard pins

Dial feet restoration

Crystal and glass customisation

Laser spot soldering

The refinishing process is a complex one, starting with the methodical disassembling of the entire watch part by part. In some cases, special tools are developed just to refinish certain case parts. Refinishing has to be done in a separate room so that dust particles do not contaminate the movement of the watch.

Each case part of the watch is polished individually to reinstate its original factory specifications, and only after this does the reassembling of the watch take place. Even the screw heads are polished, such that by the time we are done with the refinishing, your watch will look as new and stunning as the day you first took it home.

These pictures show the refinishing works that we have done for our customers.

PART I BEFORE AFTER

PART II BEFORE AFTER

Sandblasting is a metal-cleaning process which if not done professionally, could lead to some dimensional damages to the watch, i.e., loss of metal from the surface being cleaned. It is an effective cleaning process for hard surfaces by way of using high pressure air. Sandblasting can be used for smoothing, shaping and cleaning hard surfaces. The effect of sandblasting is similar to that of using sandpaper, but the former provides a largely more even finishing. Note the picture below. The timepiece sent in by our customer shows an obvious rough and speckled finishing that is certainly way out of factory's specifications. After our servicing, you will notice a much softer, uniform, matte, clean and bright finish. This is the desired effect and is only made possible by using the correct procedures, methods and tools. The sheen and lustre seen in the "after" picture is associated with factory's specifications. More importantly, there are no dimensional changes in the metal which would ruin the look of the valuable timepiece.

BEFORE AFTER