While cooking oil can provide a temporary or emergency form of lubrication for bearings, it is generally not recommended for long-term or critical applications due to its properties and limitations compared to dedicated bearing lubricants.
The Role of Lubrication in Bearings
Bearings require lubrication to reduce friction, minimize wear, dissipate heat, and prevent corrosion. Proper lubrication extends the lifespan and maintains the performance of machinery.
Cooking Oil as a Lubricant: What the Science Says
Cooking oils, such as Canola Oil and Olive Oil, are vegetable-based oils with lubricating properties. Interestingly, in tests evaluating performance, some vegetable oils have shown potential. For instance, one test specifically noted:
In order from longest to shortest rolls on average, it went from the Canola Oil, to the Olive Oil, to the Mineral Oil. The results of my tests were very interesting. When it showed me that the vegetable oils did better that the Mineral Oil, I was awed.
This suggests that under specific conditions or in certain simple tests, vegetable oils like canola and olive oil can provide lubrication and might even outperform standard mineral oil in a narrow metric like rolling distance after initial lubrication.
Why Cooking Oil Is Not Ideal for Most Bearing Applications
Despite showing lubrication potential in some tests, cooking oils have significant drawbacks when used for typical bearing lubrication:
- Oxidation and Gumming: Cooking oils degrade rapidly when exposed to air and heat, which are common in operational bearings. This process, called oxidation, causes the oil to thicken, become gummy, or even solidify, leading to increased friction, reduced performance, and potential bearing failure.
- Lower Thermal Stability: They cannot withstand the higher temperatures often generated within bearings, breaking down and losing their lubricating film more quickly than conventional lubricants.
- Lack of Additives: Standard bearing greases and oils contain additives specifically designed to improve performance, such as anti-wear agents, extreme pressure (EP) additives, rust inhibitors, and anti-foaming agents. Cooking oils lack these crucial components.
- Water Absorption: Many cooking oils can absorb water, which promotes corrosion and reduces lubricating effectiveness.
- Not Designed for Specific Loads and Speeds: Conventional lubricants are formulated to handle specific load capacities, speeds, and operating environments for bearings, which cooking oils are not designed to do.
Comparison: Cooking Oil vs. Bearing Grease
| Feature | Cooking Oil (e.g., Canola, Olive) | Bearing Grease/Oil |
|---|---|---|
| Primary Function | Food Preparation | Bearing Lubrication & Protection |
| Oxidation Rate | High | Low |
| Thermal Stability | Low | High |
| Additives | Generally None | Formulated with Additives |
| Water Resistance | Low | High (Varies by Type) |
| Long-Term Use | Not Recommended | Recommended |
Conclusion
While a simple test might show cooking oils like canola or olive oil providing lubrication performance comparable to or even better than mineral oil in that specific scenario, this does not translate to suitability for typical bearing applications. The rapid degradation and lack of protective additives make them a poor choice for reliable, long-term bearing lubrication. Stick to lubricants specifically designed for bearings to ensure optimal performance and longevity.
