Minute Repeater - Ron DeCorte
Technical Data - "Minute Repeater" Ron DeCorte
Patek Philippe wristwatch, Ref. 5207 platinum. Grand Complication with minute repeater instantaneous perpetual calendar in apertures and tourbillon
Minute repeaters share a long heritage with a large range of other watches, more commonly known as striking watches, of which minute repeaters are considered one of the most complicated. Only eclipsed by the grand/petite sonnerie in its complexity, the minute repeater will sound the time to the nearest minute upon demand. In most circumstances a minute repeater is not combined with other complications since the complexity of the mechanism requires a great deal of space within the watch. Anyone who has had a minute repeater on their wrist, or in their hands, can attest to the magic of hearing the time without looking at the hands.
Like most things in life, necessity is the mother of all invention. Striking watches are no exception to this rule. Light, or as we know it in modern terms, electric light, is a relatively new convenience. Knowing the time in the middle of the night was not an easy task several hundred years ago. Clocks had been fitted with striking mechanisms that could sound the time to the closest hour, and in some cases the closest quarter hour. But to have a large clock striking the time every hour, or quarter hour, was a bit disruptive to the sleeping process. A more discrete manner of knowing the time, without the need of lighting a candle or lamp, was the answer.
Photo of modern set of wire gongs
The first examples of striking watches were “dumb” repeaters, which struck the hours by simple thuds on the case that made no sound and could only be detected if the watch was held in your hand. With time, a bell, usually attached to the inner back cover of the watch, was introduced for the hammer to strike, and the first chiming watches were born. Evolution brought forth watches that not only chimed the hour, but also the quarter hour (quarter repeater), and the closest half-quarter hour (half-quarter repeater). It was the early 19th century when A. L. Breguet and his team of watchmakers designed a watch that would strike the hours, quarters, and minutes; and instead of a bell, a set of coiled wire gongs was introduced to reduce space and provide different tones. By the late 19th century the minute repeater mechanism had been greatly perfected to its current configuration.
Because minute repeating mechanisms are almost always situated under the dial (there a few rare exceptions) -- since this affords the best physical location -- the mechanics and activation are seldom seen, with the exception of watchmakers, or in the case of a rare sapphire dial watch. To see a minute repeater in action is a bit bewildering, with many functions happening in rapid succession in order to give a timely sound to the exact time at hand. There are more than 100 uniquely special components essential to complete a minute repeating mechanism, and each component must be manufactured to extremely exact tolerances. And even with the most precise manufacturing techniques there is the requirement that a highly qualified watchmaker must make many slight adjustments in order to achieve the exact tone and cadence of the strike.
Gongs have replaced the bell, which only had a single tone of vibration. However, gongs are tricky in their tuning and require a fine ear and subtle hands to reveal their true character. Each gong, there are two gongs in most minute repeaters, must be hand adjusted by a skilled watchmaker, in order to be in complete harmonic resonance. The strength of strike of each hammer must also be individually adjusted so as not to overpower the gongs, sending them into overload. Sensitivity of the hand and ear are of major importance at this critical stage of bringing a minute repeater to life.
As with any striking watch something must strike the gongs, and in this case it is the hammers. As there are generally two gongs in a typical minute repeater, there are two hammers. The weight of each hammer must be matched to the corresponding gong. Furthermore, and possibly more important, the strength of the spring that controls each hammer must be exactly proportional to the hammer weight, otherwise resulting in a blurred sound, either too weak or too strong. Again this tuning of the hammer springs by a master watchmaker is part and parcel of the overall quality of a fine minute repeater.
Hammers, left and right middle
Listen to the tone of the Minute Repeater Ref. 5016J
The symphonic stage is now set. First, the hours are struck on the lower pitched gong, and then the quarter-hour is struck on both gongs, finally the minutes are struck on the higher pitched gong. For instance, if the time is 10:52, the minute repeater will strike ten times on the lower pitched gong, next it will mark the 3rd quarter of the hour on both the high and low pitched gongs, and finally seven minutes past the quarter will be marked on the higher pitched gong. The passage of time is now complete and has been recorded by the ear. This symphony might seem simple, but the mechanics to make it possible require extreme skills, both manually and audibly.
At the heart of every minute repeater is the “minute snail”. There are four leafs, each with 14 steps that keep track of the minutes each hour. But wait a minute, 14 X 4 equals only 56 minutes, what’s this about? Well, the answer isn’t such a big mystery. Four times each hour, at the beginning of each quarter, no minutes are struck since at these times the first minute of the quarters has not been reached. There are two other snails, besides the minute snail that act as the brains of a minute repeater. A “quarter snail”, with four steps, is responsible for counting the quarter hours, and an “hour snail”, with 12 steps is responsible for the hours. It is these three snails, and their associated racks, that give minute repeaters their voice, allowing them to sing the time to a minute fraction of the hour.
Minute snail, quarter snail, Hour snail
There are no short cuts to making a fine minute repeater. Most watchmakers consider this the ultimate single complication in watchmaking; everything must be perfect to bring about the precision of striking, and the perfect sound. So it is that every minute repeater produced by Patek Philippe is personally auditioned by Philippe Stern or Thierry Stern, and upon his approval, is then recorded for the Patek Philippe archives as a matter of posterity.