Under the Loupe/An overview of Modern Lubricants Used in Watchmaking
An Overview of Modern Lubricants
Used in Watchmaking
The reduction or, better still, complete elimination of friction in the functioning of the motion works a timepiece is an issue of utmost importance. The great 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 the watchmaker in our never ending quest for horological perfection.
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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 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 accepted practices in the area of lubrication are always changing. The information presented here is current as of March 2007 and will no doubt change 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, is likely to eliminate the need for lubrication of the escape wheel teeth and pallets 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 pithwood in those every two weeks.
Preparation
Prior to lubricating a watch, the timepiece should first be entirely disassembled, including the removal of all cap jewels and setting parts. While a number of watchmakers leave the mainspring in the barrel for cleaning to promote efficiency in the turnover of their services, the barrels of automatic watches should always be completely disassembled and the barrel walls cleaned with a disposable absorbing material such as a q-tip. The graphite and MoS2 based lubricants used on the barrel walls of automatic watches are particularly insoluble and it is best to try and remove as much of the lubricant as possible before washing in a watch-cleaning solution.
Once disassembled the parts must be thoroughly cleaned. Ultrasonic equipped cleaning machines take to this task well, and do a better job of removing any old or dirty oil that has dried or become thick along the inner walls of the jewel bushings than traditional cleaning machines or hand washing methods can. 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, bearing mounted rotor, and reversing wheels of a number of calibers 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, 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 mechanism is ready for 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.
The Essentials
Moebius Synt-A-Lube 9010
An oil which used to be used ad hoc throughout the going train, it is now commonly agreed upon that it is best suited for application to balance jewels and escape wheel jewels. In a pinch, it can also be used to lubricate the pallet stones, however Moebius 941 and 9415 are better suited for this application. Balance jewels should be treated with epilame prior to oiling.
Moebius 941/Moebius 9415
The Moebius 941 series of oils is designed specifically for the friction plane that exists between the pallet jewels and teeth of the escape wheel. Ideally, each tooth of the escape wheel should receive the same amount of oil and lubrication should not be notable on the upper or lower portions of the impulse face of the pallets as these areas do not come into contact with the escape wheel teeth. In no case should any lubrication appear on the top or bottom planes of the pallet as capillarity will tend to cause the oil to creep away from its intended plane of action.
Moebius 9415 was designed to remain in place while providing lubrication for the rapid and forceful impacts of the escape wheel teeth in watches with a beats per hour count of 28,800 and higher. Moebius 941 is not recommended for high beat escapements, however it is becoming more and more commonplace for 9415 to be used in movements with a beat rate of less than 28,800.
Lubrication to the pallet stones/escape wheel teeth should be applied sparingly. Both the pallet and escape wheel should be treated with epilame prior to lubrication.
Moebius Microgliss D5 and Moebius Synt-HP
Microgliss D5 is a versatile and economic solution to many of the friction reducing needs of the typical mechanical watch movement. It can be applied to almost all posts and setting components, and is commonly used to lubricate most of the jewels in the gear train. It has also come to replace Moebius 8300 in the lubrication of the setting and winding systems in most watches.
Microgliss D5 is slowly being phased out by the currently more expensive and further refined line of Synthetic High Pressure lubricants (Synt-HP for short) 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 2824. 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 aimed at 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.
Molykote DX
Molykote DX is a mineral based, adhesive lubricant that can handle very heavy loads. Molykote is less fluid than Moebius D5 and will not drip or run. White in colour, it 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 suited to meet the friction needs of certain applications in mechanical chronograph systems.
Moebius 8201
The physical properties of Moebius 8201 make it perfectly suited for the lubrication needs of the barrel wall in automatic watches, allowing the mainspring to hold fast until the load bearing threshold of the lubricant is met. Moebius 8201 utilizes the same base as Moebius 8200 mainspring grease, to which a lamella structured material known as molybdenumdisulphide (aka. Moly Disulphide, Moly, or MoS2) has been added. Moly is a peculiar lubricating material in that friction is reduced as load and surface speeds increase. On a molecular level, as the compound is compressed the weaker bonds of the sulphur layers slip against the more strongly bonded molybdenum layers. When power from the automatic winding mechanism becomes too great, friction drops and the spring glides against the barrel wall until the power stored in the mainspring dips below the load bearing threshold of the molybdenumdisulphide. If moly, or a similar lamella structured material like graphite, is not applied to the barrel wall of an automatic watch, the watch in question is highly susceptible the risk of breakage and wear of parts.
Moebius Quartz Oil 9000
Moebius Quartz Oil 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
Moebius 9020
More viscous than Moebius 9010, Moebius 9020 is suited for use on slow moving parts and large caliber watches, such as pocket watches, where 9010 would not otherwise be suitable. It can also be substituted in many cases for Moebius 8141 when it is specified for lubrication of the train jewels.
Moebius 9030
Has a much higher viscosity and slightly lower range of operating temperature than Moebius 9010 and 9020.
Moebius 9040
Designed specifically for use in very cold environments, it 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.
Lubeta V105
Designed especially for the lubrication of reversing wheels. Apply sparingly.
Lubeta V106
Designed for the lubrication of the ball bearings used in oscillating weights. Apply sparingly.
Jismaa 124/Moebius 9501
Both lubricants are synthetic greases recommended for medium pressure, high friction surfaces. Used for lubrication between the canon pinion and driver, as well as on some components of chronograph systems.
PML Stem Grease W-10
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
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.
Rolex MR4
A highly viscous grease, this gel-like lubricant is highly recommended for use on the winding and time setting works of a watch.
Kluber 125
A relatively new grease, recommended by ETA for use on the outer coil of the mainspring of some of their automatic watches.
Dinosaurs
Moebius 8141
A quasi-viscous lubricant, superior to Moebius 8200 for the lubrication of mainsprings in mid-size watches when such lubrication is called for. Note that new, white-alloy mainsprings should never be lubricated. As they do not need to be greased it should also be noted that they do not require washing to remove any old lubrication and washing may actually tend to damage the teflon-like, frictionless coating that is applied to these mainsprings. Old stock mainsprings, however, in most cases, do require lubrication.
Moebius 8200
A penetrating grease designed for effective and lasting lubrication of the mainspring.
Moebius 8300
A viscous grease, used for the winding and setting works of a watch.
Concluding remarks
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.