Oiling steel knife blades, even if they're not porous, is a crucial step in preventing rust and corrosion
. Here's why:

• Protective Barrier: Oil creates a thin, protective layer on the blade surface that acts as a barrier, preventing moisture and oxygen from coming into direct contact with the steel. This is especially important for carbon steel knives, which are more susceptible to rust compared to stainless steel.
• Disruption of Oxidation: When water and oxygen come into contact with iron, a chemical reaction called oxidation occurs, leading to rust formation. Oil disrupts this process, preventing the breakdown of the metal structure.
• Maintaining Appearance: Oiling helps preserve the knife's aesthetic appeal by preventing discoloration, staining, and dulling.
• Enhanced Performance: A properly oiled blade experiences reduced friction during cutting, which contributes to maintaining a sharp edge for a longer period.
• Protection for Moving Parts: For folding knives, oiling the pivot points and hinges ensures smooth action and prevents debris buildup that can impede the mechanism. 

Important considerations:

• Food-Safe Oil: For kitchen knives and pocket knifes as well as hunting knives that come into contact with food, it's essential to use food-grade Blade oil or specialized knife oil like Horace Whitlock's Food Grade Knife Blade Cleaner and Lubricant.
• Avoid using cooking oils, as they can turn rancid and leave a sticky residue.
• Cleaning and Drying First: Before oiling, ensure the knife is thoroughly cleaned and completely dry, as trapped moisture under the oil can lead to rust.
• Even, Thin Coat: Apply a few drops of oil to a clean cloth and wipe it evenly along the blade, then wipe off any excess. 

By incorporating oiling into your knife maintenance routine, you can significantly extend the lifespan of your knives and ensure they remain in top condition for years to come. 

As Horace Whitlock was quoted during an interview "Don't just sharpen the blade........Maintain the knife"

It's a misconception that steel knife blades are truly non-porous. While the surface may appear smooth and solid to the naked eye, even microscopic imperfections in the metal can allow moisture to penetrate and initiate the corrosion process
. This is particularly true for high carbon steel blades, which are more susceptible to rust than stainless steel due to their higher carbon content. 
Here's why oiling is crucial even for seemingly non-porous steel blades:

• Rust Prevention: Oil creates a protective barrier, essentially acting as a shield between the steel and the elements that cause rust, particularly moisture and oxygen.
• Corrosion Protection: Beyond simple rust, oil also helps to protect against corrosion, preventing discoloration and degradation of the blade over time.
• Reduced Friction: A well-oiled blade experiences less friction during cutting, improving the smoothness and efficiency of your cuts.
• Prolonged Sharpness: By minimizing corrosion and friction, oil helps to maintain the blade's sharp edge for longer periods, reducing the frequency of sharpening.
• Enhanced Appearance: Regular oiling contributes to a polished, clean appearance, preventing staining and dulling of the blade's surface.
• Protection for Moving Parts: For folding knives, oil lubricates the pivot points and hinges, ensuring smooth opening and closing mechanisms. 
• In essence, oiling acts as a preventative measure to safeguard your knife blade against the detrimental effects of rust, corrosion, and wear.