A dull knife is more dangerous to you than to whatever you want to cut with it. This guide will show you how to care for your military or bushcraft knife. Whether you’re carrying a Varusteleka Jääkäripuukko in the wilderness or battlefield or a tactical folder in the urban jungle, don’t abuse it, or it will turn on you. You have been warned.
Pre-emptive care
The first part of knife maintenance is pre-emptive care. Neglect is the enemy of knives, and it will give you craploads of unnecessary work afterward. If you leave your knife wet and dirty, it will rust. Even stainless steel can rust if neglected or exposed to corrosive elements, such as seawater.
Clean and dry your knife after each use. If it requires washing, do it by hand. Never put your knife in a fckn dishwasher. Oil the carbon steel knives before storing them. Use a non-toxic, non-reactive, neutral oil, such as mineral oil, MCT oil, or Canola oil. Salted lard is a very bad idea.
Rust removal
If your knife has rusted, it isn’t the end of the world, and it can be easily cleaned. However, the better you take care of your blade, the less time you need to spend on rubbing it. There are various rust-removal methods, such as chemical treatments, fine-grit sandpaper, and steel wool. They all can work. The benefit of sandpaper is that it is easy to use, readily available, and can reach tight spots.
If you choose sandpaper, choose the grit based on how rusty your blade is. For fine surface rust, you can go with a fine-grit paper, and for a blade that you buried in the sea for eons, you need the coarsest you can get and an exorcist. Rub the blade thoroughly with sandpaper until no rust remains. Remember that rubbing the edge with the paper will dull the blade and lead to a blood pact with the knife. Adding water may make the process easier, but then you should use a specific “wet sandpaper”. Dry sandpaper will quickly turn to mush. Be thorough and check your progress. Pay special attention to small nooks and crannies. Once you are done, clean any possible crap, dry the blade, and oil it.
Blade angles
Before you start sharpening the bejesus out of your knife, you need to know something about sharpening angles. Different knives use different angles for a reason. The smaller the angle, the sharper the edge is—but also the more fragile. So, if you need to do some batoning or hacking through zombie skulls, you need a wider angle.
The riddle of steel: Does the blade material matter?
Most blades are made either from carbon steel or stainless steel. Within these, there are, of course, loads of different variations, and then there are specialty blades that we won’t cover here. Stainless steel blades keep their edge longer, but they are more difficult to sharpen. Carbon-steel knives lose their edge faster but are easier to sharpen.
The sharpening techniques are the same, but since stainless steel is harder, you just need to spend a lot more time on stainless steel blades.
Sharpening tools
1. Pull-through sharpeners
Pull-through sharpeners are fast, affordable, and easy to use for quick knife maintenance. They usually use carbide or ceramic slots to create a fixed-angle edge, often 20 degrees. They are best suited for beginners or restoring dull, lower-end knives rather than precise sharpening. They can aggressively remove metal, potentially ruining high-end knife geometries.
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Pros: Fast, idiot-proof, fits in a pocket.
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Cons: They eat your steel. They force a single, generic angle, leaving a rough edge.
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Verdict: Use it on a cheap knife, but keep it away from your high-end blades unless it’s an absolute emergency, you are out of other options, and you need to cut something quickly
2. Sharpening rods (steel, ceramic & diamond)
A honing rod is a good tool for field maintenance. Ceramic rods remove a lot less material than diamond rods, so they are safer for beginners. Steel rods straighten rolled edges without removing material.
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Pros: Lightweight, great for touching up an edge between tasks. Excellent for folding knives with recurve blades.
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Cons: Keeping an even angle requires a steady hand. It’s hard to reprofile a damaged edge with just a rod.
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Verdict: A handy option for your ruck. Great for quick maintenance, poor for repair.
3. Guided systems (Gatco, Lansky, etc.)
These come with several stones and use clamps and rods to maintain the selected blade angle.
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Pros: Guarantees a perfect, consistent bevel every time. Even a beginner can get a hair-shaving edge.
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Cons: Slow to set up. Not suited for field use. Doesn't work on very long or oddly shaped blades.
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Verdict: Great for perfectionists who want a "factory edge" without learning the skill of freehand sharpening. Too slow and bulky for field use.
4. Electric Wheels (Tormek, etc)
The heavy artillery. Water-cooled grinding wheels. These are what professionals who need to sharpen lots of blades use.
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Pros: Fast, incredibly precise, and the water cooling prevents the steel from losing its temper (becoming soft from heat).
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Cons: Expensive and heavy. It’s a workshop tool, not a field tool.
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Verdict: If you have a fleet of knives and other tools needing sharpening or you’ve severely chipped your blade, the Tormek is the king.
The master class: Sharpening stones
If you want to be self-reliant and get the best possible result, learn to use sharpening stones.
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Pros: You can freely select the angle you want. By choosing the right stones, you can make a very dull, damaged blade sharp enough to shave beavers (Castor Canadensis, you dirty rascal). Smaller stones are also easy to carry along in the field.
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Cons: Good stones are fairly expensive, and you need several. Maintaining the correct angle requires practice.
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Verdict: This is the most versatile sharpening method for outdoor knives. Learn their secrets.
Grit progression
You need several sharpening stones for the best possible result. The duller the blade is, the coarser the first stone should be, or you will have to spend an eternity on it. And the sharper you want your blade to be, the finer the final tool has to be.
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Coarse (120–600 grit): For repairing chips and "resetting" the edge. If your knife is truly dull and/or damaged, start here.
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Medium (700–2,000 grit): The workhorse. This puts the actual "working edge" on the blade.
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Fine (2,000+ grit): For fine-tuning. This is how you get that hair-shaving sharpness. Go gradually higher. For experienced sharpeners, an 8,000-grit finishing stone is recommended as the endpoint, while beginners may find that 3,000 to 6,000-grit stones produce sharp enough results.
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Leather strop: No matter which stones you use, always finish with a leather strop and some honing compound. This removes the microscopic burr, turning a "sharp" knife into a "scary sharp" knife.
Oil stones vs. water stones
There are numerous types of sharpening stones, from natural to synthetic. However, the main thing for a regular user is whether the stone uses water or oil.
Sharpening stones require a liquid medium—water or oil—not for lubrication, but to act as a vehicle that floats away "swarf" (metal shavings and stone grit). Without liquid, these particles clog the stone's pores, creating a glazed surface that stops the abrasive from cutting the steel.
Waterstones are generally softer-bonded, which means the dull grit breaks away quickly to reveal fresh, sharp particles; this makes them faster and more efficient at removing material, but they wear down into hollows and require frequent flattening.
Oilstones are harder and more durable, maintaining a flat surface much longer—making them ideal for delicate or rounded carving tools—but they cut more slowly and are messier to clean. While water is convenient for outdoor use and easy to source, it can cause rust on carbon steel if not dried properly, whereas oil naturally protects the blade from corrosion.
There are also hard-bonded combination stones that can use both oil and water. However, stick with the chosen liquid once you have made your decision. Switching from water to oil may still be possible (stone must dry completely). However, the other way round is very time-consuming, because the stone has to be cleaned with solvents.
Sharpening technique
There are various sharpening techniques that provide good results. The most important thing is to maintain the correct angle without waving the knife around like a maniac. And that you sharpen all parts of the blade on both sides equally.
Since moving pictures tell more than words, check out this video for one good way to sharpen your knives.
Conclusion
Sharpening is not rocket science, but it does require some consideration regarding tool selection and some practice, especially when it comes to sharpening stones. You don’t need expensive electric systems unless you have to sharpen a lot of knives and other tools that you use daily. Or if you really like power tools. On the other hand, don’t get the cheapest crap either for high-quality knives.
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