The geometry of the Corsican knife: when the shape of the blade and the handle makes all the difference
blade ventrue, tip, ball, blade grind, thickness, curvature of the handle and balance...
Understand the technical choices that give each handcrafted Corsican knife its character and quality of use.
Two corse knives can be made in a comparable steel, have a blade of the same length and have an equivalent manufacturing quality, without offering the same sensations and behavior at cutting.
The difference is often due to their geometry.
Behind this term are very concrete choices: the curvature of the edge, the width and thickness of the blade, the position of the tip, the curve of the handle and the way in which the whole fits into the hand.
These characteristics are not independent. They participate in the personality of a knife, its effectiveness and the approval of its use.
In the Corsican cutlery, where the traditional curnichjiolu is now home to a wide range of artisanal creations, this geometry is a particularly interesting area of expression for knifemakers.
The silhouette of a knife is not only aesthetic
When you look at a profile Corsican knife, you immediately distinguish its general line.
Some models have a largely rounded blade. Others have a more elongated profile, a more marked tip or a handle whose curvature extends that of the blade.
These differences are not solely a matter of drawing.
The silhouette corresponds to what the knifemakers call the profile of the blade: its shape side view.
This geometry intervenes in the way in which the edge comes into contact with the material and in the position of the tip in relation to the hand.
However, the profile must be distinguished from the section geometry, which corresponds to the thickness distribution between the back of the blade and its wire.
These two aspects are complementary.
A blade can have an elegant and robust silhouette while presenting a relatively thin section, favorable to the cut. Another may have a close silhouette, but a thicker section intended to favour certain mechanical constraints.
It is their combination that defines much of the behaviour of the knife.
The belly of the blade: understanding the role of the curved edge
The belly is the rounded part of the edge.
It is particularly interesting in the study of Corsican knives, some of which have a large and curved blade.
When the edge is curved, its point of contact with the material can move gradually during the cutting movement.
This provision favours certain cutting or cutting gestures accompanied.
A pronounced curvature allows for a large rounded portion of the yarn.
On the other hand, a straighter edge may be of interest for cuts requiring regular support on a relatively flat surface.
This is not an opposition between good geometry and bad geometry.
The knifemaker seeks a form adapted to the vocation of its creation.
On a handcrafted Corsican knife, the curvature of the edge also contributes to the visual continuity between the blade and the handle.
This is one reason why two creations of similar dimensions may have very different characters.
The tip: a small part that influences the whole blade
The tip forms the tip of the blade, at the point of encounter of the back and the edge.
Its position influences the actions that can be carried out with precision.
A relatively low tip, close to the general grip axis, can facilitate some detail work.
A more raised tip can accompany a geometry favouring a large portion of curved edge.
The fineness of the tip also intervenes in its ability to penetrate.
A very fine tip may be particularly precise, but it retains less material than a more robust tip.
The choice therefore depends on the destination of the knife.
On Corsican artisanal creations, the design of the tip takes part in the general silhouette without the existence of a unique geometry imposed on all models.
Width and thickness: two dimensions not to be confused
The width of the blade corresponds here to the distance between its back and its edge, measured at a given location.
Its thickness corresponds to the size of the metal between the two sides, measured in particular at the back.
These two measurements describe different characteristics.
A wide blade is not necessarily thick.
It offers more height available to organize thinning of the metal towards the edge.
A narrower blade can also have excellent cutting geometry, depending on its thickness and the work of its faces.
The thickness of the back contributes to the rigidity of the blade. The amount of material kept close to the edge influences its penetration into matter.
This is why the only maximum thickness does not allow for the determination of cutting performance.
The knifemaker must take into account the full section.
The thickness behind the wire: a decisive detail
Imagine two blades whose back measures the same thickness.
On the first, the faces gradually thinn and retain little material behind the wire.
On the second, the thickness remains greater until close to the edge.
At comparable steel and sharpening, the former can more easily penetrate certain materials.
The second can present more material behind its thread, which can respond to a search for robustness.
The difference depends on the shape of the blade grind, its height and the final geometry of the edge.
This relationship between thickness and cut explains why the performance of a knife cannot be deduced solely from its steel grade.
The blade grind: give a function to the thickness of the blade
The blade grind is the work done on the faces of the blade to thin them to the edge.
She participates in section geometry.
Its role is not limited to making the blade cutting: it also determines how the material is discarded during cutting.
A relatively high blade grind can allow a gradual decrease in thickness.
A lower blade grind retains a larger portion of the blade in its initial thickness.
These configurations can meet different objectives.
In the professional criteria of the Syndicat des knifemakers Corse, a regular and symmetrical blade grind, reaching at least two thirds of the width of the blade, is one of the quality requirements assessed.
This benchmark belongs to a specific professional repository. It is not a universal rule applicable to all forms of knives.
However, it shows the importance attached to controlling proportions.
The work of the knifemaker is to obtain a coherent geometry, where the thickness, the height of blade grind and the shape of the edge correspond to the destination of the piece.
The curvature of the handle: much more than an aesthetic signature
The handle is the interface between the hand and the knife.
Its shape determines some of the gripping conditions.
A straight, slightly curved or strongly curved handle does not necessarily place the hand in the same orientation compared to the blade.
Curvature can help support the palm and influence the way the fingers surround the handle.
But it alone is not enough to define comfort.
The length, thickness, cross-section and surface condition of the handle also count.
A handle too narrow for a given hand can provide an insufficient support surface.
Too large a handle can make some catches less natural.
Therefore, there is no ideal ergonomic form for all users and for all uses.
Rather, the knifemaker seeks consistency between the drawing, dimensions and vocation of the knife.
The special case of curnichjiolu
In the traditional curnichjiolu, the handle horn gives a special place to the natural shape of the material.
The available curvature influences the silhouette that the craftsman can obtain.
The work consists of valuing this material while making a functional handle suitable for mounting the blade.
The horn is therefore not only a decorative element.
She participates directly in the architecture of the object.
This particularity explains in part why two handcrafted curnichjioli can have substantially different lines.
The handle section: round, oval or flattened
The exterior silhouette does not reveal all the geometry of the handle.
It is also necessary to consider its section, i.e. its shape when viewed perpendicularly to its length.
A relatively round section has surface continuity around the handle.
An oval section can offer more perceptible orientation markers in the hand.
A more flattened section changes the distribution of support surfaces.
These characteristics influence the grip, without a particular section being systematically preferable.
Transitions between sides also play a role.
Too marked edges can create uncomfortable pressure points, while rounded connections allow different distribution of contact with the hand.
In the craft industry, the handle is designed precisely to work on these volumes.
Polishing then finishes the surface, but it does not replace the quality of the initial shape.
Proportions: why two knives of the same length are different
The balance of a knife depends on the distribution of its mass between the blade, the handle and the various building elements.
It should not be confused with its total weight.
Two knives of identical mass can give different sensations if this mass is not distributed in the same way.
A larger blade can move the centre of gravity forward.
A heavier handle can produce the opposite effect.
The position of the centre of gravity influences in particular the feeling of weight in hand and the ease with which the knife can be oriented.
However, we must avoid defining a universal ideal position.
On a small folding knife, the sensations also depend on the total length, grip and movements made.
The choice of a handle in horn, wood or other material can change this distribution, but the shape and dimensions of the parts remain equally important.
The balance is therefore the result of the whole construction.
The balance of the knife: understanding the distribution of the masses
The total length of a knife is not enough to describe its geometry.
Two models can have an identical dimension once opened and have very different proportions.
One can favor a relatively long blade and a shorter handle.
The other can have a more compact blade combined with a handle offering more grip length.
The width of the blade, its curvature and the thickness of the handle further accentuate these differences.
On a folding knife, the geometry must also allow the blade to be housed in the handle when closed.
This constraint contributes to the overall design of the object.
The proportions are therefore not only the result of an aesthetic choice: they also depend on the construction requirements.
The knife line: when volumes form a set
A nice line doesn't necessarily match a perfect symmetry.
It is determined by the way in which the different parties respond.
The curvature of the back can visually extend the curvature of the handle.
The belly of the blade can create a contrast with a more straight upper part.
A higher point can change the silhouette without significantly changing the length of the blade.
The knifemaker works these form relationships to build a coherent set.
On an artisanal knife, a variation of a few millimetres can significantly alter the perception of the piece.
This is particularly visible on compact folding knives, whose elements must share a relatively limited volume.
The success of the drawing lies in the agreement between the different parts, rather than in the accumulation of details.
Traditional Corsican knife and contemporary creations: a freedom of forms
curnichjiolu is a major expression of the traditional island cutlery.
The Syndicat des knifemakers Corse includes, for its traditional maker’s mark CT, a balanced line, a wide and curved blade and a handle one-piece made in materials accepted by its reference.
These criteria recognize historical characteristics while leaving room for the personal expression of artisans.
However, the contemporary Corsican cutlery is not limited to this type of knife.
Other designs adopt handles made of different wood or materials, finer or larger blades, as well as various mechanical constructions.
This variety does not erase the identity of the island cutlery.
It also reflects the diversity of artisanal approaches.
It would therefore be reducing to claim that a real Corsican knife must have a definite curvature, a prescribed length or a fixed relationship between its blade and its handle.
The identity of a manufacture must be distinguished from the appearance of the object alone.
Understanding geometry is better to appreciate the work of the knifemaker
The geometry of a knife is not limited to a drawing on a sheet.
Each line corresponds to a manufacturing choice.
The width of the blade influences the possibilities of making the blade grind. The curvature of the edge contributes to the cutting movement. The position of the tip intervenes in the precision of certain gestures.
The ball and section of the handle influence the grip. The proportions and distribution of the masses participate in the general balance.
All these elements must work together.
It is this coherence that gives its technical interest to an artisanal cutlery creation.
In the Corse knifemakers, the diversity of forms allows us to recognize personal approaches, from the sobriety of the traditional curnichjiolu to the lines of the contemporary cutlery.
The beauty of a Corsican knife lies not only in the materials that make it up, but also in the intelligence of its proportions and in the mastery of its manufacture.
Discovering a handcrafted Corsican knife is as much to appreciate the work of the hand as the technical choices that give it its shape.
Couteaux Corses® — Since 2011