Frodsham’s new watch – 10 years in the making

This very special timepiece is finally unveiled!

The spoof comedy classic ‘At last the 1948 Show’ appeared on ITV in 1967. The Frodsham watch, débuting as a prototype at the BHI 150 celebrations in 2008 has become available in a mere ten years; but it has been worth the wait. From marine chronometers to tourbillon pocket watches CHAS FRODSHAM, LONDON, has only appeared on items of the highest quality. There was no point in just bringing another watch into the world, it had to be rather special; and it is.

As would be expected, the externals: case, dial, hands, finish of the visible movement, even the fitting of the strap, are superlative; reaching beyond what would be expected for the thick end of £60K (plus local taxes); but it is whats going on inside that will excite the cognoscenti. Its USP, at the heart of the movement, is the Daniels Double-Impulse Chronometer Escapement, perhaps the most perfect escapement yet achieved in a wristwatch.

A statement like that needs some justification. In 18th century cylinder escapements the escapewheel is in continuous frictional contact with the balance; like a parent pushing a child on a swing but never letting go. In pursuit of ‘detachment’ the now ubiquitous Swiss lever makes contact with the balance jewel through some 52°. From his drawings, Daniels claimed 36° for his DDICE but, using high-speed, 4,350 frames per second video, Frodsham

suggest that each escapewheel tooth is only in contact with the impulse jewel through 14° of swing. The parent is merely giving the child a brief pat on the back. The balance in a marine chronometer is impulsed by the escapewheel, but only in one direction; it’s on its own for the back swing. That’s OK in a

relatively stable environment, no ship jerks about like a wrist, or even a waistcoat pocket. To impulse in a similar way but in both directions, a pair of counter-rotating escapewheels is needed. This is the essence of Breguet’s échappement naturel, which, with the escapewheels geared together and driven by a single train, he was never able to perfect. Daniels’s conceptual break-through was to have separate trains driving each wheel. A portion of each barrel’s winding wheel can be seen in the upper corners of Figure 1.

Neither centre wheel is in its traditional location. An additional jewelled pinion can be seen driven by the great wheel, upper left. It drives the minute hand via under dial work.

The action of the escapement is illustrated, Figure 2. This is a high precision escapement and it is essential that the positioning of the components is maintained within close tolerances. Frodsham makes its own shock-resistance system for the balance staff. The commercially available versions do not reposition precisely enough.

The choice of appropriate materials throughout is striking. The train wheels are work-hardened gold and the escapewheels are titanium. Machining the latter must be a challenge but with its light weight and low inertia, titanium is an ideal material for these ‘stop, go’ components. This also applies to its use for the detent, Figure 3, which is said, before jewelling, to weigh about the same as a sesame seed. The balance is a recently developed, very stable, ternary copper alloy and the timing weights are of heavy tungsten carbide. The inertial ratio of the Frodsham balance to its detent 13,000:1, much higher than in an equivalent Swiss lever escapement’s 4,300:1. This gives the oscillator greater ‘dominion’; a concept beloved by the makers of precision pendulum clocks.

The Frodsham watch has been a long time in development and clearly no avenue for perfecting its performance has been left unexplored. Compared with the more industrial offerings of the Swiss high-end manufacturers at the same price point it is excellent value.

Figure 1: The Charles Frodsham Prototype

Figure 2: Twin barrels drive trains leading to the twin escapewheels below the balance. An additional winding wheel (not shown) induces the counter rotation. The wheel with the snail-shaped crossing, partially seen between the barrels, indicates state of wind and is part of a mechanism including an exquisite epicyclic gearbox. Note the hacking lever, with a gold pin, above the balance. To its right is a stop lever actuated before power is exhausted. A slender bridge below the balance supports the escape wheels and the detent.

Figure 3: The detent is pivoted tangentially between the escapewheels and locks and unlocks them alternately as it is rocked by the balance. This sequence shows impulse being delivered by the wheel on the right. On the return swing these steps are repeated for the anti-clockwise impulse.

Figure 4: The titanium detent after jewelling.

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