Like all machines, clocks and watches convert potential energy into movement. That energy is often stored in a wound spring or in the weights that fall under gravity. It is then translated through a series of wheels, with teeth facing out, and rings, with teeth inside, into the movement of hands or dials. These wheels and rings are arranged in three-dimensional space – front to back, top to bottom and side to side – while the position of the hands allow us to observe the fourth dimension of time.

With direct power sources and large gear ratios leading to friction, the lubrication requirements and products used in clock and watchmaking are remarkably similar to those of engines and turbines.

Neglect Over Time

Watch repairers experience challenges that many field-based lubrication engineers would be familiar with. Lubricant starvation, use of the wrong product and incorrect application are the most frequent causes of problems with clocks and watches, according to one timepiece expert.

The first service on modern clocks is often after they have stopped completely due to lack of lubrication, Chris Papworth, the chair of the British Clock and Watchmakers Guild, told LubesnGreases.

Some repair workshops use the cheapest oil available, while others buy the most expensive in the hope that it does the job well. However, the total cost of fluids to the watch or clock repairer is minimal. Bob Bartow, who maintains and repairs grandfather clocks, estimates that he uses just 7 milliliters of oil in a year, which is enough to lubricate hundreds of clocks. Observing a watch repairer at work, it is difficult to even see the lubricant applied using a miniscule pin-like tool.

We decant very small amounts of oil into specialist oil pots with glass inserts and a cover to avoid dust or other contamination. One drop could last us a week, Steve Fletcher, a third-generation clock repairer from Witney, United Kingdom, and resident expert on the BBC television program The Repair Shop, told LubesnGreases. Many inexperienced and hobby repairers contaminate their oils by applying directly from the bottle.

Many watches require three fluids – a low- and a high-viscosity liquid lubricant and sometimes a grease – to lubricate moving parts. Some mechanical watches require only two. Craftsmen also grease seals with a silicone grease.

Although the quantities of lubricant are so small, even on larger mantelpiece clocks and grandfathers, the intervals between applications can be very long.

Horologists arent necessarily experts on lubrication. I will probably see a [particular] grandfather clock two or three times in my lifetime. Thats not enough visits for a clockmaker to establish which lubricant is better or not, Papworth continued.

Combined with poor assembly, the three problems mentioned above mirror the top difficulties faced by industrial gearboxes, according to a recent member survey by the Society of Tribologists and Lubrication Engineers in the United States.

Hold Steady

Chemical instability leading to lubricant degradation is another important issue in watch lubrication. A watch worn regularly is constantly exposed to the wearers wrist temperature of around 38 degrees Celsius, moisture, skin flakes and bacteria, as well as dust and air pollution. Anyone who has worked with metalworking fluids will know that these are ideal conditions for biological breakdown of a lubricant if any bugs get into the system.

When wearers remove their watches for the night – or for longer periods with prestige watches – some pull out the winding pin to stop the watch. The thinking is that this saves the life of the battery or the spring, but it does not. It actually just opens the inside of the watch to contamination.

Larger clocks are permanently open to the environment to some degree, from partially enclosed carriage clocks to completely open clocks on found on turrets.

Turret clocks used to receive weekly visits from a clock winder, but as there are fewer people willing to do this, more clocks are fitted with an automatic winding mechanism.

We are starting to see more wear to those clocks that have been fitted with automatic winding. Clockmakers normally provided a pot of oil which could be used by the clock winder to oil the bearings when he could see that they were getting dry, Papworth said. Now these clocks are neither monitored nor lubricated regularly. This change could lead to the wider use of greases in turret clocks or more extreme pressure additives to enhance the protection by the lubricant.

These clocks are also exposed to air pollution, moisture, greater temperature ranges, birds and other small animals and their detritus, all of which finds its way into the mechanism. High-tech additives will not prevent bat droppings from fouling parts.

Mechanism of Wear

Many watches and clocks have more moving parts than those that drive the hour, minute and second hands. Some common extras are date and day wheels, while chronographs have stopwatches, which are all driven from the same power source. Clocks may have chiming and display mechanisms, such as cuckoo clocks, that are interlinked but have separate power sources. In either case, the mechanisms supporting them become increasingly complex.

The bearings in a high-quality mechanical watch are usually synthetic sapphires, which replaced natural rubies many years ago, hence them being called jewels. These jewels are drilled through and the pivot of a wheel slides into the hole. The outer face of the jewel is concave, and the assembled pivot and jewel form a small bowl that becomes the lubricant reservoir for that pivot and bearing. Watch jewels are also found in the pallets of the escapement (the assembly of tiny parts that produces the ticks) and the end stones, which are parts of the thrust bearings that act as shock absorbers at each end of the balance pivot. The pallet jewels are the only teeth on the entire power train that are lubricated, and they distinguish watches from engines, which have no teeth that are not lubricated.

The corresponding part in many clocks is a hole in a brass plate into which the steel pivot sits. The brass plate is countersunk, or indented around the hole, to form an oil reservoir. This arrangement has been in place since before the invention of the grandfather clock in the mid-17th century.

Over-oiling is another significant problem, explained Fletcher. If you over-oil [the oil sink of a clock], it runs out and forms a track that encourages the rest of the oil to run down the plate. If it stays in place, excess oil attracts dust that mixes to form a grinding paste, Fletcher said. Once this grinds the holes into misshapes, the plate must be repaired with new bushes, or a metal lining, for the hole.

Familiar Fluids

Lubricants for timepieces have common roots with industrial lubricants, and many ingredients are familiar. Natural fats and oils and their blends with mineral oils were once common and are used by some to this day. Sperm whale oil was used on some watches and is the reason that a fishy smell sometimes wafts up from antique watches opened after a long dormancy. Mechanisms lubricated with natural oils tend to gum up and stop quickly, which leads to an unintended advantage – more frequent cleaning and re-oiling, which in turn means the timepiece sustains less wear.

In the early 19th century, a German watchmaker, Hermann Moebius, recognized the exceptional properties of neatsfoot oil (a natural substance made from rendered cow shin and feet bones) for clock lubrication and founded a company producing specialty lubricants for horologists. The company survives today as part of Swiss watchmaking group Swatch and is still one of the preeminent watch lubricant suppliers.

Familiar ingredients in many modern timepiece lubricants and greases include API Group I base oils, zinc dialkyldithiophosphates, phenolic and aminic antioxidants that would be found in the majority of crankcase or industrial lubricants, polyalkyl methacrylate viscosity modifiers and lithium greases. Synthetic esters and polyalphaolefins were introduced in the 1960s and can be found in watch and industrial lubricants today.

The divergence of horological lubricant chemistry from larger-volume lubricants began in the 1950s. Again, Moebius lead the market, and one of its most widely-used synthetic oils is based on an aromatic or aliphatic polyether, well removed from most conventional lubricant base fluids.

Another fluid known as epilame is coated onto the metal parts of a watch to ensure that the lubricant stays where it is applied and does not spread. Current epilames are usually fluorinated esters carried in a volatile, non-staining solvent. Although not a lubricant, they are a class of fluid that could have applications outside this niche area, such as preventing grease loss from ball bearings.

Ultimately, the most notable difference between the movement in a timepiece and an industrial gearbox is that ring and wheel teeth do not require lubrication. Thus, the lubricants used in other parts of a timepiece are subtly different.

Time to Come

In parallel with mainstream lubricant demand, the growth of Asian economies has led to significant increases in demand for luxury items over the past 20 years. However, another similar change – drive train electrification – is less of a concern. Expensive watches and clocks are status symbols and fashion items, so their replacement by wearable computers is probably less likely than the replacement of the internal combustion engine by electric vehicles. In the meantime, the men and women with the magnifying eyeglasses will continue to maintain and repair the beautiful mechanisms produced over the past few hundred years.