Under the Loupe/An overview of Modern Lubricants Used in Watchmaking
Modern Watchmaking Lubricants
The reduction or, better still, complete elimination of friction in the functioning of mechanical timepieces is an issue of utmost importance. Abraham-Louis Breguet is quoted as having once said, "Give me the perfect oil, and I will give you the perfect watch". Two hundred years later, proper and effective lubrication of a timepiece still remains the Achilles heel of watchmakers in our never ending quest for horological perfection. The following is an overview of modern lubricants used in watchmaking.
Keeping Up To Date
While manufacturers have made leaps and bounds in the quality, consistency, and longevity of materials and lubricants used in the field of horology in the last half century, it is all for naught if the watchmaker or watch technician who repairs these timepieces is not aware of them. While lubrication (particularly of the barrel, escapement, and balance assembly) may be the greatest weakness in the effective timekeeping of a mechanical watch, one of the watchmaker's greatest strengths is to continually keep informed of industry improvements and changes in this area. Theories, technologies, and generally accepted practices for the lubrication of mechanical timepieces is always changing. The information presented here is current as of July 2012 and will no doubt evolve further in the years ahead. The recent introduction of DRIE etched silicon (often referred to in the industry by its French name silicium) parts in a number of recent prototypes and some production models is likely to eliminate the need for lubrication of the escape wheel teeth and pallet stones in modern timepieces in much the same way that treated Nivaflex mainsprings eventually eliminated the need for mainspring greases like Moebius 8200. It is recommended that all bottles of lubrcant be marked with the date of purchase and replaced every two years. Use small amounts in oiling cups, change the lubricants and pith wood or surgical sponge in those every two weeks.
Prior to lubricating a watch, the timepiece should first be pre-cleaned, then entirely disassembled, including the removal of all cap jewels and setting parts. The barrel of the watch should always be completely disassembled and the barrel walls of automatic watches cleaned manually with a disposable, absorbent material such as a Q-tip. Fran Wilson Nail Tees are particularly effective. Dirty barrel drums can also be suctioned out, with the small bench vacuum system employed in most modern watch service facilities, using a vacuum head designated for the task that has been dipped in solvent. Older graphite and molybdenum disulfide based lubricants used on the barrel walls of automatic watches are particularly insoluble and it is best to try and remove as much of this lubricant as possible before washing in a watch-cleaning solution.
Once the watch movement has been fully disassembled, the inside of each jewel should be cleaned with sharpened peg wood, the worn parts replaced, and any necessary adjustments made. Arrange the parts carefully in partitioned cleaning baskets and put them through a final cleaning. Extra care must be taken in consulting technical documents supplied by the manufacturers to ensure that any specially treated parts not intended to be washed are set aside. The mainspring, ball-bearing mounted rotor, and reversing wheels of a number of calibres fall into this category.
The improper rinsing of an ammonia based cleaning solution from a hairspring leaves a residue that will cling to and begin to gum with the spray of oil that occurs on a nanoscopic level when the escape wheel teeth impact the pallet stones. This residue is particularly hazardous in the case of an over-oiled escapement or cap jewels that have been so oiled so as to leak down the balance staff and on to the collet, eventually contaminating the hairspring. A gentle soaking in a tetrachloroethylene or trichloroethylene solvent, such as One Dip, is recommended to clean the hairspring and balance assembly. Other solvents, such as naptha and solvent H, are being adopted by more and more watchmakers due to the health problems associated with exposure to chloroethylene based solvents. The entire assembly, with the setting and cap jewel removed, can be placed in solution and moved gently back and forth for a few seconds. Remove the balance assembly and set on a piece of watchmaker's paper to dry, lifting the hairspring stud gently to free any residual liquid from between the coils.
After proper cleaning, the parts are ready for any specified surface treatments (such as Fix-O-Drop), followed by re-assembly and lubrication. Any shortcuts in the effective and proper removal of the previous lubrication will always result in less than optimal performance when the job is done.
Moebius 9010 is an oil that used to be employed throughout the going train on some calibres, it is now commonly agreed upon among modern watch manufacturers that it is best suited for application to balance jewels and escape wheel jewels.
Moebius Microgliss D5 was used widely by most manufacturers around the turn of the millennium, but has since been supplanted by the currently more expensive and further refined line of Synthetic High Pressure lubricants (Synt-HP for short) developed by Moebius. The line is offered in four varieties of differing viscosity aimed at spanning the gamut of mechanical timepieces, from small and delicate movements to larger workhorse movements like the ETA 7750. The Synt-HP series offers excellent aging stability, providing consistent viscosity over a longer period of time than Microgliss D5. It also offers a higher resistance to pressure, with superior lubrication and adherence capacity. Synt-HP 500 is suitable for pivots of the going train of small, delicate movements. Synt-HP 750 and 1000 cover mid range movements, and Synt-HP 1300 is designed to address the friction needs of more powerful, high torque movements and is even recommended for posts and setting components by some manufacturers. Moebius Synt-HP lubricants are coloured red by default, but are also available in a clear variety.
A highly viscous grease, this gel-like lubricant is highly recommended for use on the winding and time setting works of a watch.
Both of these lubricants are synthetic greases recommended for medium pressure, high friction surfaces. They are used mainly for lubrication between the canon pinion and driver, as well as on some components of chronograph systems.
Molykote DX is a mineral based, adhesive lubricant that can handle very heavy loads. Molykote is less fluid than Moebius lubricants and will not drip or run. White in colour, it is easy to tell exactly where the lubricant has been applied; though it can be almost invisible when applied in thin films. This lubricant is particularly well suited to meet the friction needs of certain applications in mechanical chronograph systems.
Lubricants for Automatic Barrels
Composed of a dry lubricant suspended in a carrier fluid, Klüber P125 is a thick, highly viscous, black grease used to lubricate the barrel wall of automatic watches. Although Klüber does not disclose the exact type of dry lubricant used in P125, the active ingredient appears to be molybdenum disulphide or a similar lamella structured material. These types of lubricants are interesting, in that friction is decreased as load and surface speeds increase. Such properties allow the lubricant to help hold the bridle of the mainspring against the barrel wall until the load bearing threshold of the material is met. As the stored energy in the mainspring increases as it is being wound, the pressure applied by the mainspring bridle against the barrel wall eventually compresses the molecules in the lubricant to such an extent that the weak bonds within its molecular structure break temporarily and “slip” across the stronger bonds. This sudden drop in friction in turn allows the spring to glide against the barrel wall until the power stored in the mainspring dips back below the load bearing threshold of the lubricant.
TEPA is a proprietary barrel wall lubricant developed by Rolex. Whiter in colour than Molykote DX and of similar viscosity, TEPA grease is a far cry from the black, molybdenum or graphite based lubricants of decades past. It is both cleaner and easier to handle than Klüber P125 and other barrel wall greases like Moebius 8201 or 8301. As with all greases intended for use on the barrel wall of automatic watches, TEPA holds the bridle of the mainspring to the barrel wall until its load bearing threshold is met, at which point it allows the mainspring the slip.
Moebius 941 is designed for use in low beat watches, at the friction plane that exists between the pallet jewels and teeth of the escape wheel.
Moebius 9415 is a thixotropic lubricant intended specifically for high-beat escapements. Its physical properties allow it to remain in place while absorbing impact and providing lubrication for the rapid and forceful blows of the escape wheel teeth in watches with a beats per hour count of 28,800 and higher.
Rolex RL-2 is a proprietary escapement grease developed by Rolex. Prior to RL-2, 2 different lubricants, which will be discussed below, were necessary to lubricate watches that ran at either a low or high frequency. Moebius 941 was tailored to low beat calibres, while its thixotropic alternative, Moebius 9415, was created specifically for high beat watches. Rolex RL-2 replaces both of these lubricants, as a stable, high performance, escapement grease.
RL-2, like Moebius 9415, is a thixotropic grease. In simple language this means that the grease liquifies (becomes less viscous) and becomes more slippery when hit with force. Thus, when a tooth of the escape wheel comes quickly into contact with the pallet fork the grease adapts to the force and helps to provide a smooth, near frictionless, surface for the escape wheel tooth to glide across. RL-2 has a more uniform consistency than Moebius 9415 and displays excellent staying power on epilame treated surfaces. It offers all of the benefits of 9415, while still allowing enough "give" to be suitable for use on low beat calibres where Moebius 941 would otherwise be necessary.
Special Purpose Lubricants for the Automatic System
Lubeta V105 is a dry, waxy lubricant suspended in a clear, sweet smelling liquid similar to that used as the carrier fluid for the ink in ball point pens. Its name is a concatenation of “lube” and “ETA” as the formula was developed by the movement manufacturer ETA SA. The product was designed to simplify the lubrication of the reversing wheels in ETA calibres while also helping to prevent over lubrication, which can be detrimental to the proper functioning of the automatic system.
Lubeta V105 is applied by submerging the reversing wheels into the solution for several seconds and then removing them to dry. Excess fluid should be blown off with a hand blower and the parts left to dry underneath a bell cover for 15 minutes. Due to the nature of the carrier fluid that the lubrication is suspended in, contact between a freshly coated part and solvent sensitive materials (such as plastic) should be avoided.
Lubricants for Quartz Watches
While greases or heavy lubricants such as Synt-HP 1300 are as suitable for the setting works of a quartz watch as they are for a mechanical watch, a specially formulated, light oil, known as quartz oil 9000 is available from Moebius for the gear train of quartz watches. The gear trains of some modern quartz watches can run efficiently with no lubrication whatsoever.
Moebius Quartz Oil 9000 is especially designed for the bushings of the rotor and going train of analog quartz watches. The oil should be applied sparingly, as excess will cause a decrease in efficiency and gain in power consumption of the timepiece.
Lubricants for Special Purposes
Designed specifically for use in very cold environments, Moebius 9040 has very low viscosity and much lower range of operating temperature than other Moebius 9000 series lubricants. Due to its extremely low viscosity at normal room temperature, the operating surfaces to which it is applied must be treated with epilame before being lubricated. Highly recommended treatment in preparation for polar exploration and high altitude flying.
An American made grease highly applauded for the silky feeling it lends to winding and setting. It can be used on the winding stem and parts of the winding and setting works.
Fomblin grease is recommend in lieu of silicone for the lubrication of gaskets in the caseback, bezel, and crown/tube system, as it can withstand the very high temperatures to which a watch is often exposed during a day on the beach or an afternoon at the pool.
It is important to note that the proper application of lubrication is just as, if not more, important than the choice of lubrication being applied. Consultation of technical guides, training courses, and the insights gained through the experience of revisiting watches you yourself have serviced in years past are all valuable means of honing and perfecting your technique.