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OILS

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1. Definition and role

Oils are fluid lubricants whose role is to reduce friction between the moving parts of a calibre. Unlike greases, their liquid consistency allows them to flow in infinitesimal quantities into the very small spaces that are the jewels, the pivots and the lifts of the Escapement. A poorly chosen oil or one applied in an incorrect quantity can cause immediate chronometric disturbances, accelerated wear, or even block the Movement. Their application requires both precise knowledge of the areas to be lubricated and a rigorous technique, as the volumes involved are measured in fractions of a nanolitre. Although invisible to the naked eye once applied, oils play a decisive role in the accuracy of running and the longevity of a movement.

2. Viscosity, a fundamental parameter

The main criterion for choosing an Oil is its viscosity, expressed in millipascal-seconds (mPa·s) or centistokes (cSt). As a general rule, viscosity decreases as one progresses through the kinematic chain of the Movement: one moves from relatively viscous lubricants at the level of the Barrel to increasingly fluid Oils when approaching the Regulating organ. This gradation is fundamental: an Oil that is too viscous on the pivots of the Escape wheel would slow down the oscillations of the Balance; an Oil that is too fluid on the pivots of the Train (wheel train) would quickly migrate out of the reservoirs. Viscosity also varies according to Temperature, which justifies the existence of specific formulations for environments with extreme Temperatures.

3. Synthetic oils (Moebius — Synt-A-Lube range series 9 010)

Moebius is the reference and virtually exclusive supplier of lubricants for watchmaking. Its range of synthetic Oils covers all the needs of a modern mechanical Movement.

The Synt-A-Lube series brings together fine universal Oils intended for fast-moving wheels and regulating parts. The 9010 (viscosity of 150 cSt) is the universal reference par excellence: fluid, stable and endowed with excellent lubricating power, it is suitable for fast-moving wheels and regulating parts. The 9014 (100 cSt) offers an intermediate viscosity between the 9 010 and the 9 030. The 9015 (150 cSt) is particularly recommended for the Lubrication of plastic components.

4. Synthetic oils (Moebius — Synta-Visco-Lube range series 9 020)

The Synta-Visco-Lube range comprises synthetic Oils of medium to high viscosity, intended for slower moving parts and areas subject to higher pressures.

The 9020 (270 cSt) is ideal for moving parts subject to moderate to high pressures, where the 9 010 would be too fluid. The 9024 (260 cSt) is also recommended for plastics. The 9026 (235 cSt) incorporates molybdenum disulfide (MoS₂) to enhance pressure resistance under increased stress. The 9027 (1060 cSt), highly viscous, is reserved for slow moving parts subject to the highest pressures.

5. Synthetic Oils for the Escapement (Moebius Syntescap 941)

The Escapement is the most delicate area to lubricate in a mechanical movement. The lifts of the pallet stone undergo repeated impacts at high frequency on the escape wheel, in a contact combining shock, sliding and friction.

The 941 (Syntescap, 110 cSt) is a 100% synthetic oil, specially formulated for lubricating the lifts. Its excellent lubricating power and aging stability make it the essential reference for this critical point of the movement. It is applied in extremely small quantities — a few nanoliters — at each lift of the pallet stones. An excess would cause an immediate disruption of the rate due to capillarity.

It should be noted that to avoid disrupting the Isochronism, the Pallets (lever) jewels are never lubricated.

6. Microgliss and silicone Oils

The Microgliss range offers mineral and mixed Oils for Micromechanics. The D series (D-2 to D-5, from 75 to 1200 cSt) covers a wide range of viscosities for varied applications combining stability and pressure resistance.

The silicone Oils stand out for their chemical Inertia and their exceptional stability at extreme Temperatures. The I-31-B (510 cSt) and the I-4 (1000 cSt) offer improved lubricating properties while benefiting from the chemical Inertia of silicone. The H-10 (11,000 cSt), extremely viscous, is used as an assembly aid and for Water resistance. Like silicone greases, these Oils should not be used indiscriminately on all parts, as some Materials are not compatible with silicones.

7. Good application practices

Applying Oils requires suitable tools: oil pegwood. The quantity is as critical as the choice of product: a Drop that is too large migrates by Capillarity out of the jewel’s reservoir, contaminates surrounding areas and disrupts proper running. Conversely, an insufficient quantity does not protect the surfaces.