Knife sharpening and 5 care principles
Nothing can withstand everything, and that’s true for knives as well. If you want your knife to stay beautiful and functional, follow a few simple guidelines.
- Use the knife in accordance with the purpose for which it was made
- Keep the knife sharp
- Take care of the steel parts of the knife
- Take care of the handle
- Take care of your knife sheath
How to use the knife
Handle the fine knife with care. The thin blade, high cut and small bevel angle provide excellent cutting ability, but such a knife is susceptible to mechanical damage to the blade and tip.
Never use the knife as a crowbar. Hardening to high hardness causes brittleness and the blade can break when prying. Especially the tip of the knife is prone to breakage.
Use an axe for chopping. Knife only as a last resort and only one that is adapted for such activity. Knives with a thicker blade, a blunter bevel angle and preferably a lens blade can tolerate chopping to a limited extent. If you really have to, cut with a swing, do not hit the back of the knife with another object, especially not a steel one. This would reliably destroy the knife.
Don’t stab the ground with a knife. Sand grains scratch the blade and dull the edge. Do not leave the knife stuck in the wood. It has moisture and various essential oils in it, so the blade could corrode. This also applies to stainless steel knives.
Do not use the handle of the knife as a mallet. It’s not really designed for that.
If possible, cut with slight pressure combined with a knife stroke perpendicular to the direction of the cut. If you just push, the blade will penetrate the material less easily.
Knife sharpening
A dull knife requires more pressure, there is a risk of breaking the blade and injuring yourself. Basic maintenance of the blade is carried out with a honing iron. Use it to flatten out small waves in the facet and pull the cutting edge out. The honing iron does not remove material from the blade, so the knife wears only minimally. It takes a little practice to use a honing iron.
When the honing iron is no longer enough, it’s time to sharpen the knife. If you have a good quality knife, avoid the various stretching sharpeners. Do not use a conventional high-speed disc sander either. If you think of using an angle grinder, you should better throw the knife away.
Knife sharpening is not just a technical maintenance of the blade, but a skill that has a fundamental impact on the functionality, life span and character of the knife. The sharpening method determines not only the final sharpness, but also the consistency of the angle, the speed of work and the degree of control over the entire process.
The most commonly used methods include hand sharpening on stones, angle-guided sharpening systems (e.g. KMFS, Kazak, TSProf) and slow-speed sharpeners such as Tormek. Each of these approaches has its own specific advantages and limitations.
Hand sharpening on stones
Hand whetstones are the traditional and purest form of knife sharpening. They use water, oil and ceramic stones in various grits — from coarse for creating a bevel to fine for polishing the edge.
Benefits:
- Maximum feel and control: Sharpening the knife is completely in the user’s hands, allowing for subtle response to the behavior of the steel, pressure and shape of the blade.
- Versatility: Almost any blade shape can be sharpened on stones, including complex curves.
- Low acquisition cost: A basic set of stones is relatively affordable and, with proper maintenance, will last for many years.
- Top-notch results: An experienced sharpener can achieve an extremely sharp and fine edge.
Disadvantages:
- High skill requirements: Maintaining a constant angle is difficult for beginners.
- Time-consuming: The process is slower and requires concentration and patience.
- Dependence on experience: The result varies significantly depending on the skill of the grinder.
Sharpening systems with angle adjustment
These systems use mechanical guidance that fixes the angle of the knife sharpening. The knife is clamped and the sharpening stones or rods move along the guides at a precisely set angle.
This group includes, for example, the KMFS, Kazak and TSProf systems.
Most systems work with one working stone, the KMFS system works simultaneously with two stones on both sides of the blade.
Advantages:
- Perfect angle consistency: The greatest benefit lies in the repeatability and symmetry of the edge.
- Suitable for beginners and professionals: Even less experienced users can achieve a very high-quality result.
- Wide range of adjustment options: The angle can be precisely defined according to the type of knife and application.
- Efficiency: After setting up the system, the work is fast and predictable.
Disadvantages:
- Higher purchase price: Quality systems represent a larger investment.
- Preparation time: Clamping the knife and adjusting the angle takes more time than with stones.
- Less contact with the material: Some sharpeners lack a direct feel for the steel and pressure.
Low-speed disc grinders
Low-speed grinders are electric devices with a water-cooled grinding wheel that operates at low speeds, minimizing the risk of overheating the steel. The brand that sets the standard here and that others only try to come close to is Tormek.
Advantages:
- High material removal rate: Ideal for severely dulled or damaged blades.
- Steel overheating protection: Low speeds and water cooling prevent the blade from burning out.
- Consistency: Repeatable results can be achieved thanks to fixtures.
- Low physical effort: The machine does most of the work for the user.
Disadvantages:
- High price: Low-speed grinders are among the most expensive solutions.
- Risk of excessive removal: Too much material can be removed if you are not careful.
- Less “craftsmanship” feeling: The process is more mechanical and less personal.
- Space and maintenance: The device requires space, water, and regular maintenance.
Belt grinders
Belt grinders work similarly to disc grinders, only instead of a disc, the grinding is done on a grinding belt. This solution makes sense for a knife maker who will also use the basic knife machine (belt grinder) for sharpening. However, a prerequisite is that the grinder has a regulated belt speed and the ability to reverse.
When grinding on a belt grinder, we can use fixtures designed for rotary grinders, such as blade holders or angle gauges. The Tormek range is a great advantage in this regard.
The advantages and disadvantages are similar to those of a slow-speed disc grinder.
Summary
There is no universally best way to sharpen a knife — it all depends on your experience, goals, and the number of knives you sharpen.
- Hand-held stones are appreciated by those who seek maximum control and a crafty experience.
- Guide systems are ideal for precision, repeatability, and perfect blade geometry.
- Slow-speed sharpeners excel in speed and efficiency with a larger volume of work.
- Many knifemakers and enthusiasts therefore combine multiple methods — for example, rough shaping on a machine and final fine-tuning on stones. The right approach to sharpening is the key to a long knife life and the joy of using it.
I personally use a belt sharpener, classic hand-held stones, and two types of guide systems, depending on the situation.
Whatever sharpening method you use, make sure that the sharpening stones are of high quality. The difference between a good and a bad stone is in the speed of sharpening, the homogeneity of the material and therefore the quality of the sharpening, and the rate of wear of the stone.
Grinding stones can be natural or synthetic (a variety of materials). Diamond grinding surfaces are often used for coarser grinding.
The difference in price between a high-end and an “ordinary” grinding stone is large. Therefore, it is a good idea to consider all your requirements and expectations before purchasing. For occasional grinding, a mid-range stone will do the trick, but for professionals, top quality is worth it, especially because of the time savings and the quality of the work performed.
How to use a honíng iron
How to grind on stones
How to care for the blade
In the case of knives constructed with a hidden tang, this means taking care of the blade, and in the case of full-tang knives also of the handle. Carbon steel needs to be kept oily at all times. It is possible to use synthetic preservative oils, but if you use the knife to cut food, it must be a food-grade oil. A popular way of preserving the blade is bacon – stick the knife in it and it’s preserved. Camellia oil is also suitable.
In the case of corrosion-resistant steels, preservation may not be so meticulous, but especially in corrosive environments, they certainly benefit from oiling.
It must be taken into account that some foods contain aggressive substances that cause colour changes on carbon steels. You cannot prevent the patina from forming unless you always wipe and preserve the knife immediately after use. For example, citrus fruits, mustard, tomatoes and onions have this effect.
How to care for a knife handle
Handles made of synthetic materials and stabilized wood need virtually no maintenance, but it is different with wood without stabilization. When I make the wood I impregnate it with natural oil and protect the surface with hard natural wax, but these materials should be renewed after a while. For the home procedure, for example, linseed oil is suitable, which you rub on the handle and polish with flannel after it dries.
How to care for a leather knife sheath
The leather also needs to be cared for. Properly treated leather resists moisture and does not crack. It is enough to soak the sheath once in a while with some leather care product without added dye, there is a wide choice on the market. I personally like beeswax products the best because they smell so good.