For knives, the grinding angle is the angle between the blade and the grinding surface or the angle of the bevel to the vertical between the cutting edge and the back of the blade. It is critical to both the sharpness and the durability of a blade. The choice of sharpening angle depends heavily on the type of knife and its intended use.
Before you start sharpening knives, there are a few basic things you need to know to get the best results. The sharpening angle is the most important factor.
The grinding angle depends on how the grinding units are in contact with the knife. For knives ground on both sides, the grinding angle is half the cutting angle. For knives ground on one side, the grinding angle is equal to the cutting angle.
Influence of the grinding angle on the cutting properties
Sharpness: A smaller angle produces a sharper cutting edge that glides more easily through materials. This is particularly important for precise cuts and fine work.
Durability: A larger angle increases the resistance of the cutting edge to wear and damage. A larger angle is more likely to be found on solid, relatively blunt cutting edges such as axes or machetes.
Cutting performance and efficiency: The correct grinding angle ensures that the knife works efficiently, the edge lasts longer and cutting is easier.
Factors for determining the correct grinding angle
Purpose of the knife: The type of task a knife will be used for determines the optimum sharpening angle. Kitchen knives, such as filleting knives, for fine, delicate work require smaller angles, whereas outdoor knives, for example, require larger angles for more tougher tasks.
Blade material: Harder steels can be ground with sharper angles as they are less susceptible to wear. Softer steels, on the other hand, require larger angles to ensure maximum edge life and therefore sharpness.
Personal preferences and usage frequency: People who use their knives a lot and are prepared to sharpen them frequently may prefer smaller angles. Occasional users, on the other hand, may prefer more robust cutting edges.
How can I find out the original grinding angle of my knife?
The original grinding angle of a knife should normally be given in the user manual or manufacturer's information. However, the grinding angle is almost inevitably changed when the knife is first sharpened. The original angle can therefore rarely be maintained exactly.
How can I check the grinding angle? The pencil method will help you!
The pin method is a very simple way of determining the current grinding angle (the original grinding angle for new knives). This makes it easy to determine if the angle is being maintained correctly.
This is done by colouring the edge, or better still the entire bevel, with a permanent marker. After a few strokes with our V-Sharp knife sharpeners you can tell if you have chosen the right angle by the colour removal. Depending on whether the colour is being removed from the cutting edge or the top of the bevel, the angle needs to be increased or decreased.
When the colour has completely disappeared on both sides, the blade is sharpened evenly.
Should I change the grinding angle?
This is not about 'should'. Changing the grinding angle once is inevitable, as the exact original angle can rarely be maintained. It is only important to maintain the resulting angle consistently. This is essential for minimising blade removal and wear.
Of course, the grinding angle can be deliberately changed or adjusted if the intended use requires it. However, this is not intended by the manufacturer and, depending on the type of steel, may result in a duller blade.
Detailed grinding angle ranges
10-17 degrees
Characteristics: The acute angle produces extremely sharp cutting edges that are ideal for very precise and delicate cutting work.
Usage: Typical of high quality Japanese chef's knives such as Santoku, Nakiri or Gyuto, but also filleting and paring knives. These knives are designed for fine cutting and the preparation of fish, vegetables and boneless meat.
Pros: The cutting edge is very sharp, ideal for fine cuts.
Cons: The blade is more susceptible to damage and is therefore not suitable for hard materials or rough work.
18-25 degrees
Characteristics: These knives offer a good balance between sharpness and durability. The edge is sharp enough for precise cutting, yet tough enough for everyday use in the kitchen.
Usage: This angle is often found on western kitchen knives such as chef's knives, carving knives, utility knives and bread knives and is ideal for slicing, chopping and mincing. Pocket knives also usually use this angle, making them versatile tools for everyday tasks and outdoor activities.
Pros: A good compromise between sharpness and durability, making it particularly versatile.
Cons: The cutting edges are less sharp than on knives with a smaller angle.
25-30 degrees
Characteristics: These angles result in a very robust cutting edge that can withstand heavy loads. The blades are less sharp, but very resistant to wear and damage.
Usage: Excellent for outdoor, hunting and survival knives designed for rough work and cutting hard materials such as wood and ropes.
Pros: Highly resistant cutting edge, ideal for tough and demanding applications.
Cons: Less sharp, not ideal for fine cutting.
30 degrees and above
Characteristics: These extremely blunt angles are rarely used for normal knives, as they produce a very tough but hardly sharp edge.
Usage: They are used for specialised tools such as axes and hatchets, machetes and swords, where extreme durability is more important than sharpness. They are ideal for cutting through dense undergrowth and vegetation.
Pros: Extremely resistant, practically impervious to damage.
Cons: Very low sharpness, therefore unsuitable for most cutting applications.
Common sharpening problems and solutions
Non-uniform angle: Depending on the sharpening method, it can be difficult to maintain a specific angle. Angle guides are available for whetstones, for example. Knife sharpeners with a blade guide, such as the ones we offer, do not even have this problem.
Blade does not become sharp: The grinding angle may be too large. Try adjusting the angle. It is also possible that the blade is just very dull and takes longer to sharpen. In this case, the pencil method described above may help you.
Conclusion
Overview table of the grinding angle ranges and common blade types:
| Grinding angle range | Blade types |
|---|---|
| 10-17 degrees | paring knives, all-purpose knives, other small kitchen knives, Japanese knives, carving knives, filleting knives |
| 18-25 degrees | chef's knives, bread knives, steak knives, Deba knives, pocket knives, hunting knives, survival knives, combat knives |
| 25-30 degrees | cleavers, machetes |
| more than 30 degrees | axes, scissors |
The grinding angle is a key factor in the performance of a knife. Understanding the different sharpening angles and their effect on sharpness and durability is crucial to choosing the right angle. Adjusting the grinding angle to suit specific requirements and materials will ensure optimum cutting performance and blade life.
Which one is the right one for you?
