Angular contact ball bearings ensure the effective functioning and reliability of many mechanical systems in boats. These components are manufactured with high precision, bearing both radial and axial forces. Thus, it becomes mandatory in applications with high performance and durability requirements. Nevertheless, the proper operation and increase of service life of these bearings implies regular and appropriate maintenance services. This guide is written to help the reader with the basic concepts related to the maintenance of angular contact ball bearings fitted in boats to avoid costly breakdowns and understand some of the critical steps involved in sustaining functionality. Everything from general care to actual disassembly and repair tools is covered, making this guide an excellent resource for seasoned boaters and those just getting started with marine maintenance related to angular contact ball bearings.
What are angular contact ball bearings, and why are they essential for boats?
Understanding the role of angular contact ball bearings in marine applications
Ball bearings have been critical to the engineering sector due to their ability to simultaneously provide radial and axial loads. They are commonly used in propeller shafts, rudder systems, and gearboxes, all components of boat systems.
These ball bearings have an inclined contact angle and an increased axial capacity, which allows them to bear loads efficiently and accurately.
Contact Angle: It usually follows a metric between 15° and 40°, combined with increased spindle rotation, for efficient axial loading.
Load Capacity: Marine split bearings are reported to have a dynamic load-bearing force several times exceeding a few thousand Newton, which is heavily reliant on their manufacturing material and composition.
Material Composition: Stainless steel, along with alloys of higher strength, is one of the most commonly used alloys for marine environments due to its resistance to rust and corrosion.
Seals and Cutting Fluid: Shields, as well as pre-lubrication, have made it possible to restrict water from entering and require providing lubrication management.
Integrating ball bearings into marine systems improves their reliability and durability, especially their ability to withstand harsh conditions such as heavy loads, vibrations, and saltwater.
Key benefits of angular contact ball bearings for boat performance
Increased Load-Carrying Capacity: These bearings are manufactured to simultaneously accommodate axial and radial loads under certain conditions, including marine applications where the forces acting on shafts and valve stems are uncontrollable and may vary occasionally. The standard contact angle, approximately 15º and 40º, provides the optimal load-carrying capacity and stability configuration.
High-speed Operation: Thanks to their precise and balanced construction, these bearings can achieve more rotation. This allows for adjusting the propeller shafts and other rotating parts of the seacraft. Bearings with lower friction and higher speed, such as limiting speeds of 20000 RPM or more, positively affect performance.
Resistance to Environmental Stress: These angular contact ball bearings are made from anti-corrosion materials and have effective seals, which reduces their vulnerability to heavy exposure to seawater. This prevents rust or material failure, guaranteeing a long lifespan and efficient performance even in harsh seawater environments.
Less Vibration and Noise: Proper assembly of the elements and smooth rolling elements lessen vibration and noise, enhancing comfort and effectiveness during use. Higher-grade bearings, which come with advanced lubrication, tend to wear out less over time and guarantee quiet operations.
Thermal Stability: These bearings must endure high temperatures due to long hours of continuous work. However, grease is required to maintain consistency, and specific designs associated with the components can operate at temperatures reaching 150 degrees Celsius and higher.
Angulated contact ball bearings increase the durability and efficiency of marine systems. As such, they are an essential part of modern boat engineering.
Typical applications of angular contact ball bearings in marine machinery
Due to their nature of withstanding combined axial and radial loads, angular contact ball bearings are widely used in different machinery. These include:
Ship Propulsion Systems: The angular contact ball bearings are utilized in the ship’s propulsion shaft and thruster shaft assemblies as they can withstand axial forces created due to the rotation of the shaft at high speeds. These bearings within these systems can operate around speeds of 10,000 RPM and can withstand axial forces between 10 to 50 Kilo Newtons.
Marine Gears And Transmissions: Shear forces must be transferred in marine gears; therefore, angular contact ball bearings are used to ensure smooth boat anchoring. These bearings can withstand critical load factors of around 20 kN while ensuring the gear set is aligned perfectly.
Pumps and Compressors: Air and seawater pumps rely heavily on angular contact ball bearings. These bearings can operate at critical temperatures between 120°C and 150°C and withstand high temperatures and constant load fluctuations.
Cranes and Winches: In these systems, angular contact ball bearings can withstand radial loads of around 30 kN, ensuring stability while lifting heavy loads.
Navigation and Control Systems: Various machinery, such as gyroscopes and automatic steering systems, rely on angular contact ball bearings. These bearings are susceptible to any change in mechanical load and offer a much smoother rotation.
Appropriate angular contact ball bearings must be chosen in precise detail based on criteria such as operating speed, load, and temperature to ensure maximum and dependable performance in different sea environments.
How do I properly lubricate angular contact ball bearings for marine use?
Selecting the proper lubricant for marine angular contact ball bearings
There has been a recent development in lubricants specifically for marine environments. Marine environments are pretty aggressive, so there is a great need for a lubricant that withstands harsh conditions without support limitations. Thus, it revolves around resisting corrosion resistance, water washout resistance, and thermal stability. In light of these requirements, some critical parameters must be considered:
Temperature and Viscosity: Marine lubricants are typically rated between ISO VG 68 and 150, but the lubricant temperatures are deemed a more significant challenge as they range from -20C to 120C. A good oil film must be present to withstand shear with progressive loads.
Corrosion: Calcium sulphonate or anti-corrosion agents are vital to preventing saltwater damage.
Water: To stand moisture, it is imperative to use lubricants with low water washout percentages to prevent losing any further function. It is ideal to have anything below 5%.
Load-bearing: Steel pressure or better-allowing additives must improve the lubricant’s performance to assist with radial and axial load.
For continuous outstanding performance in marines with ball bearings, it is best to routinely check for levels of lubrication potential and apply recommended products.
Proper lubrication techniques to ensure optimal bearing performance
Use Suitable Lubricant: Use lubricants of appropriate viscosity and additives per angular contact ball bearings requirements. A lubricant with a viscosity index of about 100 to 150 cSt at 40 °C is indicated in marine services, provided the speed and load work well. Use corrosion inhibitors and EP additives to improve strength at high temperatures.
Ensure Adequate Quantity of Lubricant: The bearing’s performance can deteriorate if too much or not enough lubrication is applied. In the case of grease-lubricated bearings, the housing cavity should be filled to 30-50% of its volume but capacity so that while adequate grease is provided, excess heat is not generated.
Control Lubricant Temperature: The temperature of the bearings should be maintained within appropriate limit ranges that depend on the lubricant used, but they are usually between 70 °C 90°C. Too much heat can cause lubrication varnish and other heat damage; therefore, monitoring the temperature regularly is essential.
Regular Re-Lubrication Schedule: The periodicity for re-lubrication, as provided by the manufacturers, should be observed concerning operational speed, load, and ambient conditions. For example, re-lubrication may occur after every 3000 to 5000 hrs of running for those bearings that work under increased radial loads, but fewer apps may be extended.
Contamination Control: Appropriate seals, filters, and Drying Breathers must protect bearings from water, dirt, and other particles. To maintain the lubricant’s crucial elements and the bearing’s overall integrity, a water contamination level of no more than 200 ppm is recommended.
Angular contact ball bearings can be made more efficient while maximizing their life by following these procedures and checking the technical parameters even in harsh marine conditions.
Frequency of lubrication for marine angular contact ball bearings
The relubrication procedure for marine angular contact ball bearings is a function of specific conditions, the load, speed, or differences in the temperature range or atmospheric pressure. These considerations should generally guide relubrication cycles:
Operating Speed: The higher the speed, the more sinew and heat-bearing elements generate; therefore, lubrication must be administered more often. You can ascertain the speed factor (n × dm) and check catalogs for intervals.
Load Conditions: Adding heavyweights to bearing elements can escalate damage, resulting in the need to complete more frequent lubrication cycles. Such weights must be inspected to ensure they are not beyond the manufacturer’s specifications.
Operating Temperature: Bearing fellows exposed to high-temperature ranges will experience the quicker degradation of oils and other lubricants. Where temperatures go beyond the usual (i.e. 150F or 65C) it is better to cut down on the length between two lubrication sessions as fastened oils or lubricants malfunction more regularly.
Environmental Contaminants: The weather in which the bearing will find itself plays an integral role; the marine environment exposes the bearing to more moisture, salt, and dirt, thus increasing the degradation rate. Those contained in such environments might need lubrication every week or two or perhaps every couple of months, depending on the levels they are exposed to.
Lubrication type: Lastly, relubrication frequency also varies between different types of lubricants, such as oil or grease. High-grade and marine-rated lubricants resistant to water can allow longer intervals between sessions.
Considering these technical parameters, a relubrication schedule that is most efficient and guarantees maximum reliability for marine applications can be formulated.
What are the signs of wear and damage in angular contact ball bearings?
Common indicators of bearing wear in marine applications
Various methods may provide insight into the state of angular contact bearings when they are sick underwater. To me, an integrator of mechanical systems, a general deterioration of surface contact between forged fittings and fish shields can be seen in the increased vibration and noise during operation. Bearings should also not be checking for gees, rather, an increase in operating temperature will provide clues regarding lack of sufficient lubrication and pumping load. Obvious signs of damage include a pitted or core texture with a bearing finishing off with an unusual color fading.
Vibration Levels: Excessive increase in vibration amplitude might be due to one or two factors: wear, imbalance, or misalignment. This should never be the case. If otherwise, advanced monitors in rotation analysis should be put to use.
Temperature Range: A lubrication problem or overloading can be suspected only if the temperature exceeds the set operating range of 80C to 100C in most cases.
Lubrication Condition: If your lubricant retains a contaminated texture, expect poor performance, however to refrain from such incidents the cleanliness and viscosity of the lubricant needs constant assessment.
Load Conditions: Barring axial or radial loads unnecessarily burdens angular contact ball bearings beyond the framed load point and hampers growth.
Visual Inspection: Rounding off with a glance around would not do, physical signs of wear, such as pitting, cracks or fretting corrosion need to be taken into notice during general overhaul.
The systematic treatment of these parameters allows me to detect potential bearing problems and eliminate them early to conserve reliability in marine applications.
How to inspect angular contact ball bearings for damage
Regarding the angular contact ball bearings examination, I follow a stable work sequence so that nothing is missed.
Visual Inspection: I microscopically inspect the surrounding area of the balls to look for signs of pitting, cracking, or fretting corrosion. These markings indicate that the bearing is exceeding its operational limits.
Check for Deformation: I have also found the presence of warping or deformation in the bearing, which I suspect occurred due to the bearing being subjected to an excessive amount of axial or radial load beyond its rated capacity by the manufacturer.
Lubrication Assessment: I evaluate how much the lubrication has been adequate. Poor lubrication or contaminated lubricant can hinder performance and lead to overheating or damage. The lubricant’s viscosity and classification were controlled to ensure the required standards for the use were met.
Noise and Vibration Testing: I would listen for any possible noise or measure vibrations during an operation cycle using only the necessary instruments. Noise or vibration levels above or below normal can also indicate internal failure, an out-of-alignment condition, or severe contamination by debris in the rotating assembly.
Measurement of Radial Clearance and Axial Play: I also measure these two parameters to ensure they conform to the manufacturer’s manual. Exceeding these limits may indicate component wear or incorrect mounting pressure during assembly.
Focusing on these technical parameters during inspections helps me guarantee that the bearings will sustain efficient operation and reduce the chances of failure in essential systems.
When to replace angular contact ball bearings in boat machinery
Everything relies on the specific team member in charge of monitoring the performance of angular contact ball bearings and other technical parameters. If a replacement is deemed necessary, he should take a look at the following conditions:
Excessive Vibration or Noise: Some components of the system, such as races or rolling elements that are cracked or worn out, will tend to create excessive noise and vibration when in operation, which is an abnormal occurrence as a standard bearing should operate seamlessly.
Elevated Operating Temperatures: If the temperature exceeds the manufacturer’s predetermined threshold, it could mean overheating caused by a malfunctioning lubricant, which might indicate a need for replacement.
Radial Clearance and Axial Play Outside Specifications: Such incidents should be noted and monitored closely to ascertain the tolerance limits advised by the manufacturer; otherwise, it means excessive preloading was applied, hence the degradation of the bearing along with the reduction of its operational capabilities and lifespan.
Visible Wear or Corrosion: If damage such as rust, scoring, or pitting is evident, the bearing may require replacement due to excessive structural wear. These are significant signs of surface damage.
Lubrication Contamination or Leakage: A damaged bearing that requires replacement will allow lubrication with debris and water present to leak, all while smoothly operating the system, further damaging the system and making the need for a replacement unpreventable.
Regular replacement allows for smooth functioning as long as these indicators are in check order and the manufacturer’s guidelines for each standard are adhered to.
How can I protect angular contact ball bearings from marine environmental factors?
Effective sealing solutions for marine angular contact ball bearings
When protecting angular contact ball bearings from harsh marine conditions, I always use high-quality sealing solutions for extreme environments. This includes using contact seals made of rubber or polymers as double lip seals that are perfect for sealing against the penetration of water, salt, or any impurities. In addition, corrosion-resistant, non-contact labyrinth seals prevent damage while acting as a barrier. The key technical parameters I look at are:
IP Rating: To ensure that dust does not penetrate, I look for seals with at least IP66 ratings and high-pressure water jets.
Temperature Range: I search for seals with operating temperatures between—20C (-4F) and 120C (248F) for marine applications.
Corrosion Resistance: I select seals coated in PTFE or nickel plated for protection from salt water.
Seal Friction: I measure the friction torque of the seals to ensure they don’t use too much power while still being effective in the prolonged use of the bearing.
Naturally, when I consider strengthening the performance and reliability of angular contact ball bearings in marine applications, the first step I take is pairing robust sealing solutions with proper inspections and regular maintenance.
Preventing corrosion in angular contact ball bearings used in boats
Corrosion in angular contact ball bearings, especially topological ones that are designed for marine environments, places a strain on the performance capability of the bearings. The best way to go about it is to focus on a few prominent structural choices:
Material Composition: I utilize life-cost practical bearings. Such bearings have a ceramic and or stainless steel composition. The salient component of any bearing that is astonishingly right but is also wrong is a stainless steel grade like 440C, which is inexorably target-resistant
Anti-Corrosive Coatings: The coatings I tend to apply are PTFE, nickel plating, or even chromium, which are all anti-corrosive elements in essence. The coatings enhance performance and supersede factors such as harmful moisture, allowing the bearings to last for an extended period.
Lubrication: Marine bearings are best suited for use in the context of anti-corrosive lubricants. Such lubricants come within proximity to bearing components and thus create a layer that protects air and water rust from the elements.
Water Repellence: It is essential to note whether seals are present at bearing system junctures. Ideally, seals designed with an IP67 or higher rating should be used. These seals cannot be immersed entirely and are opaque to high-pressure water.
Maintenance Schedule: Interestingly, the bearings’ self-guiding mechanism is irrefutably slated for optimal control, and their maintenance schedule focuses on enhancement.
By applying such measures, I can help prevent corrosion-related failures and optimize the performance of angular contact ball bearings used in boats operating in challenging marine environments.
Best practices for storing and handling marine bearings
In preserving and using marine bearings, I make it a point to always adhere to the following best practices:
Proper Storage Environment: I store bearings in a clean, climate-controlled facility. Such a space generally maintains a relative humidity level of less than 60%, preventing condensation or corrosion. Bearings are kept at a constant temperature of 14 to 122 degrees Fahrenheit so they do not undergo thermal expansion or extreme temperature fluctuations.
Original Packaging: No use of the bearings until needed means that the bearings transportation from the original location to the storage is made in the original packaging. On such a measure, an antifouling layer would be enough to shield them from dirt, moisture, and other debris.
Handling Precautions: When handling bearings, I always ensure my hands are clean and dry. This prevents dirt, oil, or self-sweat from transferring to the bearings. I also avoid dropping something or placing bearings under impact, which might deform their shape or cause internal damage.
Positioning During Storage: I place larger bearings horizontally, which does not apply tangential loads or indicate distortions. Edging the bearings vertically could lead to thyroid letting else wear from the inequitably steep angle.
Checking Before Use: each bearing undergoes a thorough inspection to avoid any signs of corrosion, contamination, or unilateral damages before being incorporated into the installation process. I remove and change any bearings that are not in their ready-to-use state for the smooth operation of the system.
These actions allow me to guarantee that my marine bearings are adequately maintained, enhancing their effectiveness and reliability in harsh circumstances.
How do I ensure proper angular contact ball bearings installation in marine machinery?
A step-by-step guide to installing angular contact ball bearings in boats
Preparation and Inspection: To begin the installation, I look for bearing housings and shafts and ensure their tolerances are adequate. Angled contact ball bearings can support an axial load in either direction, but the shaft tolerance range is usually an H5 fit, and the housing bore has to be an H6 or H7 fit. However, alignment accuracy is generally regarded as high, considering the shaft diameter.
Lubrication: As indicated, I also use a specified amount and type of lubricant, usually oil or grease, recommended by the respective manufacturer, since it is this greasing that helps reduce friction and overheating otherwise, which will disable practical and functional operation to occur. When mounting marine vessels, I select a penetrating lubricant that is tough and practical to use in moist and corrosive environments since it’s designed for marine applications.
Positioning the Bearings: Installing angular contact ball bearings requires proper orientation according to the axial load requirements that an application may require. However, if it is the case where more axial load support is needed, I install the bearings in a back-to-back configuration or DF, and when tilting the rotor in the middle, more radial load is required. A proper orientation must be installed to ensure efficiency and avoid undue failure.
Press-Fitting the Bearings: The press-fit process defines essential factors, such as the hydraulic and mechanical details, to begin with, and for the edgewise support. Besides, it is also important to note that controlled force applications allow mounting the bearings without risking damage to the devices. In other cases, pressure must be applied to the upper portion if the inner ring is mounted onto a shaft. In contrast, other external pressure is applied towards the outer region when the device is fitted into the housing. I closely watched the process to ensure that the allowable force values did not exceed the safe range defined by the manufacturer.
Checking Clearances: In a broader context, after the bearing is installed in its final position, the focus shifts to the device’s clearances to ensure the application is successful. The criteria for success involve most of the angular contact ball bearings achieving the desired preload. Continued adjustment of the preloading through the shims or bolts after using a torque wrench to ensure preloading is in the median range, which could result in operating correctly, is also essential for efficiency.
Final Assessment: As claimed before, the primary purpose of the prime objectives defined in the broader context surveys was to focus on mounting parameters satisfactorily integrated inside the assembly. Moreover, these encompassed defining parameters such as volumes of sealant or throughout the vicinity of the bearings that were set out to be corrosion-free, and proper coverage was applied. This would cover every parameter balanced, from rotating the parts overhand to preemptively differentiating and segregating their operational masses while dry.
Considering all these factors and undertaking all these procedures step-wise, I am now confident about the durability and performance of my assembled marine machinery and, more significantly, their angular contact ball-bearing installation.
Common installation mistakes to avoid
It is reasonable to bear in mind that one of the most critical requirements for achieving the stipulated efficiency and durability of angular contact ball bearings is to avoid some of the most apparent mistakes. I would mention them as follows:
Setting The Preload Incorrectly: It is crucial to note that the angular contact bearing requires some degree of compression, as failing to meet that designated limit will result in insufficient load capacity and overheating. For those reasons, it is advisable to set up the axial clearance as instructed; in this case, an axial clearance of .02 to .04 millimeters does indeed suffice. Variance in torque is a non-issue if the right tools are used.
Incorrect Lubrication: Whether excessive or inadequate, Lubrication is vital for standard applications as it maintains the life of the bearings. Therefore, I always follow the manufacturer’s stipulated limitations, whether a lithium grease or a more general grease, as this prevents more significant issues from arising.
Debris: Dust, water, or debris can serve as the leading causes of failure for a bearing if the proper precautions aren’t taken. Even additional cleaning shouldn’t hurt, as I only use that specific shaft and housing once it has been carefully sterilized.
Preloading Misalignment Deviation: If left unattended, it becomes a stressor for the bearing, and if compression is a concern, then so is uneven wear. Rather than taking a viewing guess, I utilize feeler gauges and dial indicators to mitigate that risk. Even 0.01 mm becomes an ulterior force to calculate when dealing with such minutiae detail.
Not completing the documentation: Not properly documenting all parameters pertinent to installation, such as torque values, preload adjustments, and applicable lubrication details, may pose hurdles during troubleshooting. Quite per the parameters above, I always make a point of recording all of these to facilitate future maintenance and operation verification.
Concentrating on these likely shortcomings and verifying the parameters will ensure that bearing installation is done reliably in all cases.
Tools and equipment needed for proper bearing installation
To achieve the required results while installing the bearings in place, a wide range of specialized tools and equipment come into play:
Torque Wrenches: These are essential in tightening the bolts to the specific torque parameters the bearing manufacturers have put in place, thereby not allowing the bearing to be over or under-tightened and misaligned.
Feeler Gauges and Dial Indicators: These devices are pivotal in measuring gaps with alignment tolerances of up to 0.01 mm. This factor helps avoid uneven wear and provides an extended bearing life span.
Bearing Pullers and Pushers: These enable the end components of the shaft to be fitted with bearings easily or removed without incurring mechanical abuse.
Lubrication Tools: Tape or paint is also essential in lubrication such as when referred to a grease gun or an oiler, the proper form and quantity must be used according to the bearing requirements. For instance, I ensure that the oil pressure does not exceed 30 to 50 psi to avoid damage to the seal.
Sealing Tools are handy for putting seals in place precisely as they are required to exclude foreign materials. I also have seal conditioners, which I use to keep foreign material out and keep the seal tight for long-term use.
Documentation Tools: These can be paper or smart devices that record and save specific tools’ torque, alignment, and lubrication characteristics for future reference.
I am assured of an effective and dependable settlement process by utilizing these tools and observing the prescribed technical constants. This process also reduces the threat of bearing overloading at initiation and ensures maximum bearing efficiency.
Frequently Asked Questions (FAQs)
Q: What maintenance procedures should be performed on angular contact bearings found on boats?
A: Cleaning, lubricating, adjusting, and realigning angular contact bearings are general cleaning and maintenance practices for boats. It’s also important to check that the marine lubricant is indeed marine grade, that there are no signs of corrosion, and that the bearing is sealed against water. Good upkeep allows for a longer bearing lifespan and maintains the working condition of various boat system parts.
Q: How frequently should I check my boat’s angular contact ball bearings?
A: Testing your boat’s angular contact ball bearings on a minimum of one per season basis or every hundred hours, whichever comes first, is deemed fit. Still, if you use your boat in harsh and rugged situations or even at a high flow rate, you may need more excellent performance regularly the next time. Ensure you follow all instructions the manufacturer provides for your item’s specifications.
Q: Under what conditions will my angular contact bearings begin to have grinding noise or vibration?
A: Notable wear on the inner or outer rings, noise, vibrations, overheating, damage to the cage, and corrosion of any components will all indicate the strengthening of your angular contact bearings. Many argue that bearings should be replaced slowly because this will wear and tear the rest of my other boat parts, which is invalid.
Q: How must I maintain my marine angular contact bearings well-maintained in saltwater?
A: Rust-preventative materials, such as stainless steel bearings, can be used whenever possible. Moreover, water-resistant lubricants are also very useful in protecting marine bearings. Complete the sealing so there is no dry sand on such bearings, and marine salt water must be removed with fresh water. Along with thorough inspection and maintenance, corrosion can be avoided.
Q: What lubricant do you recommend for the angular ball bearings of my boats?
A: Make sure you use grease for the marine grade boat; it is water resistant and avoids corrosion. Companies such as SKF now have specific lubricants that can be used for marine grease. Ensure the grease is approved with the other materials and worth the operating pressure and temperature. If marine grade grease is not working for you, remember to check what lubricant is in your product manual or consult the bearings provider.
Q: How do I perform the alignment task in an angular contact bearing in my boat machinery?
A: A consequence of an improper alignment of angular contact bearings is the reduction of the bearing’s performance, life span, or both. Examine the surface of the shaft and the surface of the housing for any physical damage, as well as dirt. Alignment should allow measurement and be adjusted with the aid of precision tools. For double-row bearings or bearing pairs, care should also be taken about the preload settings. If you’re not confident about how to align the bearing, you should seek assistance from a technician or the bearing distributor.
Q: May I apply a self-aligning ball bearing instead of an angular contact bearing to my boat?
A: Conversely, fully self-aligning ball bearings can be performed in marine applications. However, they’re not substitutable in angular contact bearings. One of the angles or pairs of angles in every bearing application relates to the amount of load angled or combinations of those loads. Always contact the bearing expert or Machine manufacturer before doing it to guarantee its integrity and performance.
Q: What are the recommended procedures for storing spare angular contact bearings for my boat?
A: Spare angular contact bearings should be stored in a cool, dry place with consistent temperature. They should be kept in their original boxes or wrapped in a cover such as oil-proof paper whenever possible. The regions that may contain water, dust, or sunlight must not be allowed to come into contact with them. For long-term storage, consider applying a thin layer of oil to prevent rust. Remember to handle and touch the bearings with clean hands or gloves.
