- quality of steel
- quality of mechanical and heat treatment
- compliance with correct geometry
- quality of sharpening
So, let’s divide the blade in half and consider the possible shapes of its cross-section, the main ones include three:
- wedge-shaped
- curved lens
- convex lens
The other types are secondary and derived from the three cross-sectional types listed.
Cuneiform cross-section
A simple wedge is considered the classic form. Its peculiarity is that the planes of the blade converge and form a sharpened edge. At small angles of sharpening can achieve incredible sharpness of the blade, but if the quality of steel will be insufficient, such a blade will easily crumple or crumble when in contact with hard material.
1. Strict Wedge
2. A wedge with a lead
3.4. Flat-conical section
5. Double wedge
6. Wedge with a lead and wedge-shaped shank
7.8. Double-edged section
9. Double-edged cross-section with subsets
10. Combination of double-edged section with flat central part
11. Combination of conical section with truncated cone
12. и 13. Section in the form of a unilateral wedge – right-sided and left-sided, characteristic of the knives of the peoples of the North
Concave cross-section
The concave cross-section (lens) allows to achieve the finest sharpening. The value of the angle of the edge decreases as it gets closer to its tip, the thickness of the blade in this part also tends to zero. This is the main limitation in the use of the classic concave wedge, because such a blade can be stained even when cutting soft wood.
1. Razor section (dangerous razors)
2. 3. Widespread form of cross-section of modern hunting knives
4. Cross-section of the Russian saber
5. Characteristic form of section of medieval swords (combination of wedge-shaped blades with a wide concave chisel)
.
6. 7. Section of rapiers, bayonets, stilettos, conchars – stabbing weapons
Convex cross-section.
The convex lens (convex) is best suited for hard materials: chopping bones, branches and trees, burnt and horny limbs, etc. This cross-section is found in axes for chopping wood, combat swords and daggers, cleavers. The knife should be sharpened at a certain angle, which depends on the purpose of the tool.
1. Classic convex wedge (a cross-section characteristic of some Eastern longbow weapons)
2. Flat-convex wedge (cross-section, often found on Japanese samples of cold weapons, on some hunting knives)
.
3. Combination of flat-concave cross-section with convex shape of descents (sharpening)
.
4. Combination of flat-conical cross-section with convex form of descents
5. Lenticular cross-section (some samples of ancient swords and daggers)
6. Combination of wedge with convex shape of descenders
Having considered the types of cross-section it is possible to draw a conclusion:
- Lower blade sharpening angle – less effort to go deeper into the material
- Larger blade sharpening angle – more effort required
- Lower angle of sharpening – less blade strength
- Higher blade strength – more effort to cut
Thus large angles are needed to cut hard materials, while for cutting soft materials the angle will be much smaller. After studying the types of blade cross-section it becomes clear that for the use of the knife, it is necessary to consider the geometry of descents and angle of sharpening as the most important factors that provide comfort of work and quick results.
