A Free Sprung Balance- The Garrick Way
Garrick is currently working on its new timepiece, the sm301. The company is creating high-specification components which will be housed in the brand’s inaugural watch. Congruent with Garrick’s desire to produce a timepiece of impeccable breeding, the new model will feature an in-house free sprung balance.
The balance is the beating heart of a watch movement. It is supplied with energy from the mainspring and sets the rhythm for the escape wheel and pallet lever. The balance primarily consists of two elements, namely, the balance wheel and the balance spring.
The balance spring
Garrick has elected to source a balance spring from world-leaders Nivarox-FAR. This spiral shaped coiled spring, made of a specialist alloy appears imbued with life, pulsing with verve, expanding and contracting to a pre-determined frequency but always returning to its pre-formed shape when at rest.
The balance wheel
The balance spring is mounted within the balance wheel which oscillates to and fro as a function of the spring at its centre. Historically, the balance wheel was often affected by prevailing temperatures, losing time in warm climes and gaining time when cold. Today, this is no longer an issue as temperature compensating alloys are used. Indeed, Garrick are using Invar for the manufacture of its in-house balance wheel. Invar, an alloy with an excellent reputation, has a very low coefficient of expansion, making it temperature stable and delivering consistent results.
An index adjuster – often found in mass-produced watches
Often in modern watchmaking an index adjuster, sometimes referred to as a curb regulator, is used to alter the timekeeping of a watch. In this instance, the balance spring passes between two pins, effectively altering the spring length by moving the regulator in one of two directions, often marked with either “+” and “-“ or “fast” and “slow”. While this solution offers convenience when mass producing watches, it can disturb the isochronism of the balance spring. Moreover, the rate is more susceptible to change, depending on the position the watch is held.
A free sprung balance – the Garrick way
Conguent with the company’s desire to produce a timepiece of impeccable breeding, Garrick has chosen to fit a free sprung balance to the sm301. By adopting this approach the effective length of the balance spring remains constant. The rate keeping of the watch is achieved by adjusting the position of the hairsping and by adding mass to the rim of the balance wheel or the spokes within.The creation of a free sprung balance is more time consuming to achieve, but confers enhanced isochronism.
A common approach when creating a free sprung balance is to affix screws to the rim of a balance wheel, often termed a screwed balance. The degree to which they are tightened or loosened effects the inertia of the balance. The mass of the screws and their relative position is used to regulate the rate. Additional mass is added in a symmetrical fashion often proving time consuming and necessitating much skill on the part of the watchmaker. However, the result in superior accuracy.
Considering the airflow and mitigating errors
Garrick is a company which relentlessly seeks excellence. Careful consideration was given to the design of the balance wheel and rim. Screws attached to the rim of a balance wheel can disrupt the airflow around the balance and again, unduly influence the accuracy of the movement. The company has fitted screws in-board to the spokes of the balance wheel, providing further enhancement to the accuracy of the watch by mitigating the disruption of the airflow.
Poising the balance
The movement is expertly poised. Similar to ensuring a car wheel is balanced, the balance wheel is placed in a poising tool to ensure it runs true. Subtle adjustments are necessary to achieve perfect operation.
Excellence is time-consuming
Understandably, Garrick’s pursuit of excellence is time-consuming and demands much patience on the part of its watchmakers. However, the British company feels such attention to detail is justified in order to ensure the accurate timekeeping of the watch and to mitigate potential errors. This degree of fastidiousness not only enhances accuracy on the test bench of a watchmaking workshop, but also delivers benefits in the real-world when gracing the wearer’s wrist.
The advantages of a free sprung balance are obvious. It takes a little more effort to achieve, but the team of watchmakers at Garrick feel its customers deserve nothing less.