3. A terrible cocktail: The 'three NO's' when working with this watch: NO plans, NO space, NO mistakes

Paul Gerber was not in an enviable situation when he accepted to start working on this watch: Sure, much reputation was to gain, and of course to work on such an exceptional movement represents a watchmaker's dream. But there are three challenges that really can make your life much harder:

  • no construction plans to start with,
  • no space to accommodate the requested complications, and
  • Finally, you work with a ‚piece unique', meaning: you cannot afford any mistakes.

This chapter will shed some light into the way Mr. Gerber dealt with these three circumstances.

No plans:
You are a lucky watchmaker if your task is to modify a well documented movement: Take the technical data sheet, feed your CAD program with the data and develop your mechanism on the computer. Not necessarily easy, but a job that can be done.
But in this case, Mr. Gerber was confronted with a hundred year old movement. As I stated above, even a common watch was not serially produced after a strict specification table, and especially not such a complicated and rare piece. So what to do? The task Paul Gerber had before him required the help of CAD computer programs, so the only way out of this dilemma was to measure the cornerstones of the movement.
Basically, you fix your movement on a precisely movable table and decide on which point of your movement should serve you as a reference point, preferably an axle. All further points will be measured for their relative position to the reference point via a microscope and micrometric indicators. This is done with an old but highly precise coordinate plane-table called Hauser I, the use of which is very time-consuming. As an example, here the sub-seconds axle of a common Valjoux 7750 movement is viewed through the microscope:

Then, the movement is moved to the first point that’s position you want to know by operating the X- and Y-axis-knobs. You center it carefully with help of the microscope, and the exact position relative to the reference point can now be read on the X- and X-axis scales. Like this you go on until you have all points measured. The accuracy of the final diagram is dependent on, in addition to the slight inaccuracies inherent in the machine itself, how precisely you set the reference point and how carefully you centered all other points. Imagine what it means to measure a complicated movement like this Piguet movement....
Then, Paul Gerber made sketches of the different functional units of the movement by hand and later also by CAD computer program. Not only the mechanics, but also aesthetics like the inscriptions and engravings were rendered using 21st century computers:
Finally, modern construction tools could be applied on this movement. It is understandable that Mr. Gerber went to these extreme measures for a unique and historically significant movement. You absolutely want to test and modify the additional levers, wheels and gears before beginning to put your hands on the unrecoverable movement.
Paul Gerber not only used computers for the design of the complications, he also employed modern CNC tooling machines to get the desired precision for the parts. After cutting out, the parts were of course tested and, after the master’s approval and fine finishing of course, found their place in the works. Here you see Paul Gerber working on his CNC machine:

No space:
After the first step of the modification series was completed by Franck Muller, the owner was in the possession of a beautiful, highly complicated watch with elegant and classy case and dial, both of them finely hand-crafted after his own wishes. So beautiful, of course, that he wished to keep them. Beneath of the already difficult work Paul Gerber had to face 2 additional "complications":

  • keep the dimensions of the watch
  • place the indications to be added in a way that the existing dail can be used.

To meet these demands, most unusual solutions were found. As you can easily see, the jumping minute counter is placed concentrically with the small seconds hand at the 6 o’clock position. The Power Reserve mechanisms found their way onto the back of the movement.
The jumping minute counter mechanism is not only implemented as a small mechanical delicacy (being more sophisticated and difficult to manufacture than the common semi-instantaneous minute counter), but also as a measure to place a Chronograph into a movement where there is no space reserved for it. It is in some ways easier to transport mechanical energy via tiny levers than with a series of wheels: smaller parts can be made, less space is occupied and, in the end, less friction is produced as well.
The thinness of the clock-work also dictated the flat Split-seconds control mechanism. The column wheel for the Split-Seconds is more an octagonal rim wheel than a classic column wheel, an extremely clever and aesthetic construction!
As you can imagine, much work with literature was necessary!

No mistakes:
This is a tremendous weight on the watchmaker: if you make a mistake when modifying such a movement, it is gone for good. There is no 2nd try. Paul Gerber was well aware of this responsibility, and took every effort possible to ensure that the new mechanisms would only be added to the movement after thorough testing and evaluation. He counted not only on his experience, his calm and serene hands and his CAD drawing; he also did something that we know from the automotive industry: modeling and prototyping. He built whole (non-working) movement plates from scratch to test the chronograph mechanism before modifying the movement (which was the first step that could not be reversed). Here such a construction plate is shown:
Many corrections and improvements turned out to be necessary after these preliminary tests. Levers turned out to be too weak or not smooth enough in operation. One modification caused the other, and after several rounds of further perfecting the components, the final design was achieved. Almost every part, especially of the Chronograph, went through this procedure. To illustrate how extremely detailed the modifications were I want to give you two examples, the coupling lever (more on this in the detailed description of the Chronograph later!) and the column wheel. With all these rejected parts, one could entertain the thought of making a complete new watch.... ;-):
After Paul Gerber was sure that all parts worked properly, he hardened the parts with help of heat:
Finally, he began with the most responsible part of his job: milling out the holes from the main plate. Confronted with the fact that any mistake would destroy this beautiful movement, how could he proceed with a century of human imagination pressing on your shoulders? With the help of his innate modesty and well learned reverence for the past, this work can be managed, but NEVER without! The following pictures of the early steps during this process may illustrate Mr. Gerber’s burden:
The very last steps, quasi as a "good-bye gesture", Paul Gerber applied the final finishing touches. A very sensible work, since the surface integrity of all parts should fit to the original movement: Levers were polished and grained, plates perlaged and chamfered, wheels skeletonized and the spokes angulated. As a distinct aesthetic finesse the heart discs of the chronograph resetting mechanism were skeletonized.
The watch nearly completed, new hands had to be made. After initial drawing on the CAD program, Mr. Gerber sawed them from steel, followed by a hardening and heat-bluing treatment. Here are the pictures of the split-seconds hand given as example:
Last but not least, all 3 artists found their names engraved on the movement and on the case-back:
Contemplating about the all these challenges, one comes to the conclusion that only a modest, calm, dedicated and exceptionally skilled artist of the rare breed like Paul Gerber could master this work.
My eyes are still blinded, and all my efforts and time spent trying to find a fly in the ointment are foolish, a product of blind over assessment, and I stand calm, devout and sublimated in front of a masterpiece that speaks for itself. The aesthetics of the construction, a pure but complicated form-follows-function approach, proves the old thesis: "beauty comes from inside". Full stop, be quiet now, Magnus.
The next chapter invites you to a journey into the mechanical marvels inside the movement. Of course this a fairly technical part, but I think this unique piece deserves to be presented in detail. Therefore, may I ask you to follow me and our technical assistant John Davis to the next chapter?

The Introduction
The History
The Challenges
The complicated Complications
The Interview with Paul Gerber