A lot of times in the industry, lubricating machines is a task given to new employees because it’s thought to be a job for newer workers or apprentices. Although lubrication is a relatively easy task to perform, it is still instrumental to have a good understanding of the different types of lubricants. Doing so will ensure that the wrong type is never used for the wrong application. This will inevitably prevent machine downtime and failure.
Let’s start with the basics. There are 4 types of lubricants: Oil, Grease, Penetrating Lubricants, and Dry Lubricants. The 2 most common lubricants you’ll be dealing with daily are oil and grease, however, your facility will still be using dry and penetrating lubricants. It’s important to understand when you should and should not be using these different types of lubricants.
Oil is one of the most common lubricants found in plants. It’s a thin liquid that comes in different “weights” or viscosity, the lower the weight number, the thinner the oil. At times, additives can be mixed with the oil to prevent oxidizing and corrosion.
When to Use Oil:
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- On hinges, bearings, tool maintenance, sharpening blades
- You want to lubricate something without the resistance that’s common when using grease
- You need lubrication, but don’t want to take everything apart, so you wick the oil into a small space
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Don’t Use Oil When:
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- The machine or part needing lubrication looks to be dirty or dusty. Adding oil to a dirty or compromised area will cause additional friction or the oil will “gum up.” Additionally, if the surface isn’t clean, oils that are lower in viscosity will drip or run.
- If the surface area is wet or will become wet, this will wash the oil away. This is a common misconception since oil does make things water-resistant. However, the oil absorbs the water and over time it will lower its adhesion and wash off the parts that needed lubrication in the first place.
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Grease is made by mixing oil, a thickener, (usually a lithium-based soap) and at times additional lubricants, like PTFE (Teflon). Due to how it’s made, it has the same lubricating properties as oil. However, it’s texture and stickiness helps it adhere to surfaces better. Greases come in a variety of consistencies, the thinnest being similar to ketchup, the thickest coming close to a block of cheddar cheese.
When to Use Grease:
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- On gears, bearings, chains, linkages
- You need the lubrication to stick to the surface for a long period of time
- You want to seal out particles of dust or water droplets
- You use the machine so seldom that you may forget to oil it
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Don’t Use Grease When:
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- Your machine has fast-moving or fine parts and grease could slow it down or create too much resistance
- If you need to keep the area clean, moving parts can fling grease around
- You have fine or fast-moving mechanisms where thick grease would create too much resistance
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Penetrating Lubricant is what you’re grabbing when you have rusty jack bolts or parts with years of rust or debris on them. Penetrating lubricant is not long-lasting lubrication, it’s only use is for infiltrating tiny cracks, adding lubrication and breaking up rust.
When to Use Penetrating Lubricant:
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- Loosening stuck nuts or bolts. Whether they’re covered in rust or years of debris, this will set them free.
- Removing chewing gum (it happens), adhesive stickers, and warehouse repair tasks.
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Don’t Use Penetrating Lubricant When:
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- This cannot be used in place for other lubricants, never use this product on bearings or other parts. It doesn’t last long and will damage your machine.
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Dry Lubricant is a great alternative when you can’t use oil or grease that will attract dust and dirt. At a molecular level, the tiny particles that make up dry lubricant (like graphite) are super slippery. Dry lubricant usually comes in a spray form that’s been mixed with water, alcohol, or another solvent that eventually will evaporate away leaving behind a thin film of lubricant to reduce friction.
When to Use Dry Lubricant:
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- On threaded rods, locks, hinges
- Tiny parts that can’t be gunked up with grease or surrounding surfaces that need to remain clean
- You need to avoid using a lubricant that attracts dust or dirt
- Surfaces may be exposed to extremely high heat or pressure. If this occurs, oils will start to oxidize.
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Don’t Use Dry Lubricant When:
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- The application surface will be exposed to liquids or solvents that can wash away the remaining lubricant.
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Grease Compatibility
Knowing the proper grease compatibility is particularly important to machine maintenance because lubricant failure can have a serious impact and price tag attached to it. Dire consequences will occur when the wrong thickeners react together. You may see a reaction that causes a separation of the base oils from the thickeners. Also, the base oil may no longer stick to the grease, causing it to ooze and run out of wherever it was applied. Other reactions from mixing greases can affect the performance characteristics of a running machine such as the load, temperature, stability, and more.
We made a downloadable Grease Compatibility poster for your plant to easily see which greases mix well together.
Most grease manufacturers produce compatibility charts, but often manufacturers disagree with one another on certain thickener-type combinations. At the end of the day, compatibility testing is the best option. It will always take the base oil and elastomer into consideration, giving you the most accurate result.
We hope this helps you understand more about how to properly lubricate your machines and how to keep them running smoothly. Stay tuned for our next blog post, which will cover lubrication best practices such as cleanliness, overgreasing, oil sampling, and more.
Did you know that we offer hands-on training classes for learning about topics such as lubrication and more? Our Reliable Precision Maintenance course has expert trainers that train valuable maintenance practices to make your workplace faster and efficient to save money on unnecessary down-time down the road. Learn more about our course here.
