What is a forged knife?
“FORGE” : It is a word that talks about metal, fire and hammering…
It is also the result of several cutlery methods that you have to distinguish from cut steel.
Processes, terms, specificities … Learn how to decipher forge and choose your knife.
The different types of forged knives
A kitchen knife, a table knife or a cutlery piece can be :
- full forged, that is to say that it is realized in only one bar, without welding;
- (partially) forged, that is to say that only the knife blade, or the head of the cutlery piece, is forged, not the handle;
- Coming from 2 forged pieces ; the cutlery head and the handle are separately forged then welded the one to the other.
- With a forged bolster, when only the bolster (part between cutlery head or blade and handle) is forged.
In this case, the bolster can come from:
- the upset-forging of a cut steel sheet (not from a bar). the upset-forging ball created is then pressed and cut.
- a forged spare parts (one right, one left) that will be weld on the tang.
Art knives will mostly be forged manually.
However, most knives, are today forged mechanically.
Blade with massive forged bolster and hollow handle : Hollow handle principle
High-end classical knives and cutlery pieces
The blade or the top of the cutlery piece, hot forged, is welded to a handle, itself made from 2 shells welded together.
The all-stainless hollow handle articles are thus light and of an incomparable design with volumes.
A pressed bar : Hot forging principle
Solid handle knives and cutlery pieces
Sections are heated in a hoven to more than 1000°C (1832°F), then, as they are become malleable, they are presented one by one to a drop hammer. Equiped with the matrix (2 moulds) of the future knife, the drop hammer several times hit and crush the “round” until it takes the matrix shape.
For fully forged pieces, each blow of the drop hammer spreads the steel on each side of the bolster which is so formed in the center.
The cutlery head (blade, prong, bowl) will be shaped from one side, the handle (for solid handle pieces) or the tang (for pieces where an other material handle will be added) from the other side.
The forged piece is then die cut and, if need be, the tang is pierced so that the handle can be fixed on it.
NB: Several heat treatments are needed to obtain the raw forge piece that can now follow the finishing steps.
A compressed then pressed bar : Upset-forging principle
Volume where it matters
After cutting, the cool “round” is heated by induction in its center then pushed at both ends in order to create a ball at the heating point. This ball will be the bolster after being passed under the drop hammer.
Press without heating : Cold forging principle
Mass production
This process reduces manufacturing steps as less finishing steps are needed after cutting.
In the cutlery matter, cold forging is usually used for serial ranges.
Pieces are cheaper but shapes are thinner, more simple, steel grain is much less thin, no balance in hand, and quality and cutting edge are not as good as hot forged pieces.
What are the differences between a forged knife and a cut knife?
Visually, volume.
A steel bar allows complex shapes with varied thicknesses.
A piece cut in a steel sheet is flat. It can be curved but has no volume on the handle.
Sensory, a forged knife or a forged cutlery piece is heavier and generally more balanced in hand.
Technically and mechanically:
The different steps of forging process bring to steel a homogenous molecular structure. A bit as if all lumps of a pancakes batter have been removed.
This give strength and solidity.
As the steel is more homogeneous, the cutting edge offers a better and lasting cutting edge and is also easier to maintain.
Financially, forged pieces need more steel and more manufacturing steps.
Far from the principles of mass industrialization, each forged piece has its own asperities that require adjustments that can only be done by hand. Thus, each piece is unique. They are therefore more expensive than standardized cut pieces.
“Forged” is an obvious characteristic of top-of-the-range knives and cutlery. “Forged steel”comes with “balance”, “efficiency” and “longevity”.
But, if forge allows to manufacture high-end cutlery, it is nothing without the finishing steps which let the cutler reveals its work and the forge values.
