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Understanding the RM 004
The RM 004 for instance, created in 1999, can without doubt be considered a technical landmark of its kind. Although it is not known by many people, a split seconds chronograph is in actuality one of the most difficult complications to create. It presents tremendous challenges and demands on accuracy during parts production (with extreme tolerances of less than 2 microns), assembly, the accuracy and stability of the going train geometry and finish (as much energy is required and none can be wasted), and the perfect interplay and communication of all parts whilst the split seconds chronograph is operational. The addition of a tourbillon escapement to the RM008 to this mix only multiplies the challenge appreciably. Created starting from a blank piece of paper and spanning almost 6 years of development, the RM 004 is the first new design of split seconds chronograph realized in the last 35 years and the first of the new millenium. It uses an entirely new movement geometry in which every functional section of the split seconds chronograph movement is independently optimized, each in its specific role, comprising independent horological ‘units’ that communicate laterally. This is an entirely different approach from the classical layered and overlapping movement sections found in classical split seconds chronograph construction. This methodology, as used in the RM 004 leads to improved chronograph performance, almost eliminates the traditional stutter in the stopping and starting of the split seconds hand, and provides low friction. These effects are also aided by an extensive use of parts created in titanium allowing for a reduction in inertia and therefore less friction in the RM 004 movement than typically found in classical examples.
Another unique aspect of the RM 004 (and many other watches in the Richard Mille Watches collection) is the fact that nearly every part of the movement is visible and naked to the eye, since it is not ‘layered’ in the traditional way. For the watchmaker involved in its assembly, this means that the RM 004 demands a state of utter calm and nerves of steel during its production. One single microscopic scratch on the face of a pinion, or one tiny false move of the watchmaker’s hand, can mean that weeks of work must be disassembled and rebuilt all over again. This means that as the watch progresses ever closer towards its final completion, the greater the stress is upon the watchmaker. This combination of mechanical complexity and the difficulties inherent in the assembly of the RM 004 means that there are only a few watchmakers in the entire world who are capable of its production, which is circa 15 to 20 pieces a year. (This is excluding the production and finishing of parts, testing and quality control. If this entire time of production is counted, then the timeframe needed to complete just one RM 004 is considerable indeed.
Similar to any type of ultimate performance vehicle, a wristwatch with this kind of pedigree and attention to the cutting edge requires the owner to be well instructed in its use and functions. For instance, the pusher at 8 o’clock is used for stopping and starting the chronograph, whilst the pusher at 10 o’clock is used for resetting. The ergonomically placed pusher at 4 o’clock is used for the stopping and starting the split seconds function (which is only utilized when the chronograph is already running.) Although safety features are of course built into the watch, repeatedly depressing the chronograph reset pusher at 10 o’clock, before stopping the chronograph first, will create unnecessary stress in the movement’s mechanism that can easily cause extreme damage, since this is not a flyback chronograph. (The split seconds mechanism at 8’clock, however, can be repeatedly depressed for timing several events- as long as the chronograph is already running.)
Each component of the RM 004 is an example of extreme technique. The column wheel and a split seconds mechanism that are at the very heart of high end chronograph construction were re-designed in order to obtain optimum results, as well as to prevent the chronograph and second hands from jumping or malfunctioning. (This is a common fault that most mechanical chronographs suffer from). To achieve this, a great number of mathematical studies were carried out in order to understand the reasons for this phenomenon and to find suitable solutions on an engineering and metallurgical level. This resulted in the gear wheels and levers being redesigned and manufactured in titanium in order to reduce inertia. These components, another example of the perfection of the RM 004, also provide an additional benefit of lowering the energy consumption by approximately 50% through the reduction of friction on the spindle as well as eliminating jumping of the hands when stopped, thus increasing the chronograph’s precision.
With this aim of reducing friction, often a source of problems with a chronometer, the balance spring and the escapement have also been modified. The balance spring has a special overcoil arrangement that reduces the displacement of the center of gravity during the balance’s movement. The escapement has benefited from a new layout, and the going train has been given involute gear teeth profiles, (actually originally developed for high end engine design), that make it more efficient and less prone to possible adverse affects from changes in temperature, thus improving chronometric results.
A RM 004 is made up of an astounding 383 components of which 230 are totally unique. A number of these parts cannot even be seen with the naked eye. This makes it an extremely complicated movement in terms of parts control (trueness of dimensions to specifications), finishing, polishing, assembling and adjusting. Technically, the movement of an RM 004 is represents a challenging and quite delicate work, especially with such new materials such as carbon nanofiber, which is used in the base plate. This carbon is created from nanofibers molded in a high pressure 7.500 N/cm² with a temperature of 2000˚ C. It has a very high physical and chemical reliability. Many details of the movement of the RM 004 are examples of exceptional beauty, with various treatments, sculptured areas and sectioning (beautiful to behold as well as being lighter and more efficient).
Technical features in terms of Components parts:
383 components, 230 different parts, 79 screws
12 eccentric screws
32 pins
36 jewels
97 posts, hour-wheels and axes, 20 bridges, 1 base plate
33 wheels
28 cam-levers 17 springs
26 individual escapement components
Understanding the RM 004
A question
