Overview:
This 1896 treatise on “Friction, Lubrication, and the Lubricants in Horology” by W.T. Lewis, President of the Philadelphia Horological Society, delves into the scientific principles behind lubrication and its application in watches, chronometers, and clocks. The text emphasizes the crucial role of lubrication in minimizing friction and wear, highlighting the importance of choosing the right lubricants for specific parts and understanding their properties.
Lewis meticulously examines various lubricants, including animal oils like porpoise jaw oil and blackfish melon oil, sperm oil, bone oil, and neatsfoot oil, as well as vegetable oils like olive oil. He then explores the properties of mineral oils, particularly neutral oil and solid paraffine, emphasizing their advantages for horological lubrication due to their purity, stability, and resistance to gumming. The book delves into the characteristics of a good lubricant, including its ability to resist pressure, maintain fluidity, minimize friction, and resist decomposition, all crucial for optimal watch performance.
Key Findings:
- Friction is the enemy of accurate timekeeping: Friction in watches and clocks leads to a loss of energy, increased wear, and fluctuations in the rate.
- Lubrication is essential for longevity: Proper lubrication reduces friction, minimizing wear and tear on delicate mechanisms, extending the life of timepieces.
- Oil viscosity is crucial: The viscosity, or thickness, of oil impacts its ability to resist pressure and lubricate efficiently, requiring different oil viscosities for various watch parts.
- Temperature affects oil performance: Temperature changes can drastically alter the viscosity of oils, affecting their lubricating ability and leading to variations in timekeeping.
- Mineral oils offer significant advantages: Neutral mineral oils, particularly those free from odor and fluorescence, exhibit superior stability, resist gumming, and offer consistent performance across temperature variations, making them ideal for horological lubrication.
Learning:
- Understanding Friction: The text explains the different types of friction—sliding, rolling, and fluid—and their impact on watch mechanisms. It highlights the importance of minimizing friction by choosing appropriate materials, designing smooth surfaces, and using suitable lubricants.
- Lubrication Basics: The text delves into the properties of various lubricants, including their viscosity, ability to resist heat and cold, and susceptibility to gumming or drying. This knowledge allows horologists to choose the most suitable lubricant for each watch component.
- Oil Viscosity and Temperature: The text emphasizes the vital role of oil viscosity in watch performance and how changes in temperature impact the viscosity of different lubricants.
- Mineral Oil Advantages: The text highlights the benefits of using neutral mineral oils for lubrication, emphasizing their purity, stability, resistance to gumming, and consistent performance across temperature variations.
Historical Context:
The book was written in 1896, a time when horology was undergoing significant technological advancements. The development of new materials and manufacturing techniques, along with a growing understanding of the science behind lubrication, were transforming watchmaking. This text reflects the ongoing quest for better lubricants to improve the accuracy and longevity of timepieces.
Facts:
- Blackfish-melon oil is extracted from a head mass resembling a watermelon. This oil is highly valued for lubricating delicate machinery.
- Porpoise jaw oil and blackfish melon oil are worth from $5 to $15 per gallon. This reflects the high demand for these oils in horology.
- The blubber from porpoises and blackfish was traditionally rendered over fire, but modern steam extraction methods are more effective. Steam extraction preserves the quality of the oil better than traditional methods.
- Sperm oil, extracted from the head of the sperm whale, is a well-known lubricant. It is commonly used for general purposes but is not widely used in horology due to its temperature-sensitive viscosity.
- Bone oil is produced from the boiled bones of animals, with the finest quality coming from young cattle leg bones. The oil is purified using benzine to remove impurities.
- Neat’s-foot oil is a popular lubricant in various applications. It is extracted from the feet of cattle by gentle heat.
- Olive oil has been used as a lubricant since the early days of horology. It is prized for its non-drying properties but is susceptible to acid formation during processing.
- Mineral oils are derived from petroleum distillation and are widely used in lubrication. Their application in horology is still being explored, but some varieties are proving to be excellent lubricants.
- Paraffine oil, a refined petroleum product, is used in horology and other applications. It is obtained through a process involving superheated steam distillation and filtration.
- Neutral oils, refined paraffine oils, are frequently used for mixing with animal and vegetable oils. They are known for their stability and resistance to odor and color.
- Solid paraffine is a white, soft substance obtained from petroleum distillation. It is used in various applications, including candles and as a thick lubricant.
- The smallest pivot diameter compatible with strength and load is desirable for minimizing fluid friction. This reduces the energy lost through friction.
- The length of bearing surfaces is determined by the pressure they experience and the materials used. Proper proportions prevent abrasion and ensure oil retention.
- Capped jewels provide superior durability and lower friction compared to brass bearings. The harder, smoother surface of jewels reduces wear and tear.
- The shape of pivots and bearings should be symmetrical and smooth to minimize friction. Conical pivots are recommended for their strength and stability.
- The back-taper on pivots is crucial for oil retention and prevents oil from being drawn towards the shoulder. This design feature promotes longer oil life.
- A slight convex shape on bearing surfaces can further reduce friction by minimizing the contact area at the shoulder. This optimizes the force distribution.
- Escapement teeth should be made as small as possible for durability while retaining sufficient metal to hold oil. This balances the need for small contact surfaces with oil retention.
- The oil reservoir in capped jewels should be large enough to contain sufficient oil and prevent oil from touching the settings. Proper oil placement in the reservoir ensures consistent lubrication.
- Ferric oxide, or rust, can form on watch components due to oil degradation or lack of lubrication. This can cause wear and damage to the mechanisms.
Statistics:
- A pin’s head contains approximately 10^19 molecules. This illustrates the minuscule size of molecules.
- Water can absorb up to 600 times its own volume of ammonia gas. This highlights the porosity of liquids.
- Sperm oil can gain 2-3% in weight in 12 hours when exposed to air at 140°F. This demonstrates the oil’s tendency to absorb oxygen.
- Jenkin and Ewing’s experiments on sliding friction used a disk weighing 86 pounds with pivots 0.25 cm in diameter. This setup allowed them to study friction under controlled conditions.
- The coefficient of friction for a dry steel pivot in a steel bearing is 0.351, while with oil, it drops to 0.118. This highlights the significant friction reduction achieved by lubrication.
- The coefficient of friction for a dry steel pivot in a brass bearing is 0.195, while with oil, it drops to 0.146. This demonstrates that oil lubrication is effective across different material combinations.
- The coefficient of friction for a dry steel pivot in a polished agate bearing is 0.200, while with oil, it drops to 0.107. This shows that agate, even without oil, exhibits relatively low friction, but oil lubrication further improves performance.
- The specific gravity of neutral oil ranges from 0.8641 to 0.8333. This provides a reference point for identifying suitable neutral oil varieties.
- The boiling point of neutral oil is not less than 360°C (680°F). This indicates its stability at high temperatures.
- The melting point of commercial paraffine is typically around 43°C (109.4°F). This helps determine its suitability for different applications.
- A large watch manufacturer uses up to 8 quarts of watch oil annually. This highlights the significant volume of oil used in watch production.
- Another manufacturer uses 1.5 gallons of watch oil annually. This illustrates the variation in oil usage across different manufacturers.
- Another manufacturer uses 12 gallons of watch oil annually. This indicates the scale of oil usage for clock production.
- A chronometer maker uses approximately one pint of watch oil annually. This demonstrates the lower oil requirements for delicate mechanisms.
- One clock manufacturer uses 20 gallons of watch oil annually for clock watches and 20 gallons for clocks. This illustrates the varied oil requirements for different clock types.
- Another clock manufacturer uses 15-20 gallons of watch oil annually. This shows the substantial oil usage in clock manufacturing.
- The orifice diameter in the viscosimeter used to measure oil viscosity is 1 millimeter (0.04 inch). This provides a standardized measurement for comparing oil viscosity.
- The viscosity of one oil at 21°C (70°F) was measured to be 15 seconds, while at 38°C (100°F), it dropped to 10 seconds. This illustrates the significant change in viscosity with temperature increase.
- The viscosity of another oil at 21°C (70°F) was measured to be 25 seconds, while at 38°C (100°F), it dropped to 17 seconds. This demonstrates the varied viscosity changes in different oils.
- The time required for one oil to flow 25 centimeters at 21°C (70°F) was 21 minutes, while at 38°C (100°F), it reduced to 14 minutes. This illustrates the impact of temperature on oil flow rate.
Terms:
- Molecule: The smallest unit of a substance that retains the chemical properties of that substance.
- Pore: An invisible space separating molecules in matter.
- Gravitation: The force of attraction between any two objects with mass.
- Cohesion: The force of attraction between molecules of the same substance.
- Adhesion: The force of attraction between molecules of different substances.
- Capillarity: The phenomenon of a liquid rising in a narrow tube or between closely spaced surfaces due to the combined forces of cohesion and adhesion.
- Centrifugal Force: The outward force exerted on an object moving in a circular path.
- Viscosity: A fluid’s resistance to flow.
- Coefficient of Friction: A measure of the frictional resistance between two surfaces.
- Viscosimeter: A device used to measure the viscosity of fluids.
Examples:
- Blackfish-melon oil extraction: The text describes the process of extracting oil from the melon-shaped mass on the top of the blackfish’s head, highlighting the unique source of this prized lubricant.
- Sperm whale oil: The text explains how sperm oil is extracted from the cavity in the sperm whale’s head and how its viscosity changes with temperature, explaining its limited use in horology.
- Bone oil purification: The text details the process of purifying bone oil using benzine, demonstrating the steps involved in refining this lubricant.
- Neat’s-foot oil extraction: The text describes the traditional method of extracting neat’s-foot oil by placing the cleaned feet of cattle near a fire or in the sun.
- Olive oil purification: The text outlines the meticulous process of purifying olive oil, including the removal of acids and impurities through repeated shaking and filtration.
- Pivot proportions: The text discusses the proper proportions of pivots and bearing surfaces to minimize friction and ensure oil retention, using illustrations to explain these concepts.
- Capped jewels: The text describes the advantages of capped jewels for watch bearings, highlighting their durability and lower friction compared to brass bearings.
- Back-taper: The text explains the purpose of the back-taper on pivots, demonstrating how it prevents oil from being drawn towards the shoulder and promotes longer oil life.
- Oil reservoir in capped jewels: The text details the design of the oil reservoir in capped jewels, illustrating how the oil is placed in the reservoir and how its shape prevents oil from touching the settings.
- Viscosimeter: The text provides a detailed description of the viscosimeter used to measure oil viscosity at various temperatures, explaining how the device functions and how the measurements are obtained.
Conclusion:
“Friction, Lubrication, and the Lubricants in Horology” provides a thorough and insightful exploration of the crucial role of lubrication in the world of horology. The text underscores the importance of understanding the properties of lubricants, their effect on watch performance, and the proper methods for their application. While animal and vegetable oils were widely used in the past, Lewis highlights the advantages of neutral mineral oils, particularly their purity, stability, and consistent performance across temperature variations. This treatise serves as a valuable resource for horologists seeking to improve the accuracy, longevity, and overall performance of their timepieces, emphasizing the critical connection between science, engineering, and the delicate art of horological lubrication.