Fitting and assembly of a handmade knife

The fitting and assembly of a handcrafted knife constitute the stage where properly made parts become a coherent tool. A blade, a spring, liners, and a handle can be flawless individually and result in a mediocre knife once assembled. What matters is the relationship between the parts: how they meet, how they move, how they hold. This page explains what I adjust, what I check, and what I refuse to let pass before a knife leaves the Courpière workshop, whether it is a lockback folding knife, a friction knife, or a kitchen knife.

Fitting consists of adjusting the surfaces and contacts between the parts of a knife — blade, pivot, spring, liners, handle — to achieve smooth movement, without play, and a stable assembly over time. The final assembly only takes place after a temporary assembly, inspections, and any necessary adjustments.

Adjusting is not simply assembling

Making a part means giving it its shape, dimensions, and surface condition. Assembling means bringing the components together in the correct order. Adjusting is something else: it is correcting the way these parts interact once assembled. A plate can be flat, a blade straight, an axis of the right diameter — and the whole assembly can still rub, resist, or have play.

A few tenths of excess thickness on a spacer change the clamping of the blade. A slightly different angle on the heel alters the behavior of the spring. A barely shifted drilling distorts the overall alignment. None of these parts is "defective" when taken individually. It is their relationship that doesn’t work yet.

That is why the crafting a handmade knife does not end when the last part comes out of machining. It ends when all the parts work together.

The trial assembly: adjust before finishing

I carry out a dry fit before the finishing. It is a temporary assembly, without permanent gluing or riveting, which allows checking the knife as it will actually function: blade movement, spring contact, alignments, flushness.

This temporary assembly is taken apart and reassembled as many times as necessary. Each time, I look for points of friction, I note what catches, what resists, what gaps. A contact mark on the heel, an irregular resistance to opening, a gap between a mitre and a plate: each defect is corrected — rectifying, deburring, smoothing — then the knife is reassembled and checked again.

The logic is simple: it is always better to correct a raw piece than a polished piece. Correcting after finishing requires redoing the finish, with the risk of rounding an edge or digging a surface. Correcting early means correcting cleanly.

The parts that must work together

According to the model, a knife includes all or part of the following components:

• the blade, with its heel, a crucial contact area on a folding knife;
• thepivot, around which the blade rotates;
• the liners, which form the frame of a folding knife;
• the spring, on mechanisms that include one;
• thespacer, which fixes the spacing between the liners;
• the bolsters, when they cover the ends of the handle;
• the handle or the scales, with their fasteners: rivets, screws, or pins;
• a stop, on certain mechanisms, that limits the blade's travel.

Not all knives have all these elements. A kitchen knife has neither spring nor pivot pin; a friction knife does without a spring; some folding knives add a stop. The mechanisms of folding knives determine which parts exist — and therefore what needs to be adjusted.

Adjusting a folding knife

On a folding knife, I check the blade in every position: open, closed, and throughout the entire range between the two. The checks common to all mechanisms are as follows:

• the movement of the blade, smooth from the beginning to the end of the motion;
• the absence of lateral and vertical play;
• the centering of the blade between the liners, blade closed;
• the contact between the parts, without parasitic friction;
• the tightening of the shaft, neither blocking nor floating;
• the regularity between the specimens of the same series.

Two priorities dominate: smoothness appropriate to the mechanism and the absence of play. The rest — the sound, the "click," the resistance to opening — pertains to the sensation specific to each mechanism, not to a universal quality criterion. A Piedmontese knife, a friction knife, and a liner-lock knife do not have the same behavior or the same expected sensations. Judging them with the same framework makes no sense.

The case of the forced notch

In a detent position, the spring presses on the heel of the blade and holds it in place. This is not a lock: the spring provides resistance, it does not block the blade. The quality of the mechanism depends on the geometry of the contacts between the heel and the spring, the tension of the spring, the smoothness of the movement, and the absence of play.

Adjustment consists of refining these contact surfaces until a crisp opening, stable retention in position, and controlled closing are achieved. A spring that bends the tip of the thumb before giving way is not a sign of quality; it is often a sign of poorly adjusted contact. The resistance should come from the geometry, not from brute force. The operation of the assisted detent is detailed on a dedicated page.

The case of the friction knife

A classic friction knife has no spring. The blade is held by friction around the pivot and by the geometry of the assembly. Adjustment consists of finding the right balance: enough friction for the blade to stay in place, enough freedom for it to be handled effortlessly. Tightening the pivot to the maximum is not an adjustment; it is a lock.

On theAsmo D, a pivot screw allows this friction to be adjusted — a feature of this model, not a general rule for friction knives. And above all: a friction knife should not be judged by the "click" of a forced lock. It doesn’t have one, and this is not a flaw. The operation of a friction knife based on other qualities.

Assembling a fixed knife or a kitchen knife

Adjustment does not only concern folding knives. On a fixed knife or a kitchen knife, there is neither an axis nor a mechanism, but the relationship between the blade and the handle requires the same care.

Depending on the construction of the model, this involves:

• alignment between the blade and the handle, in both planes;
• preparation of the surfaces before fastening or gluing;
• adjustment of the scales on the tang, without gaps or overhang;
• adjustment of a guard or bolsters when the model includes them;
• the fastenings — rivets, pins — placed on the handle without stress;
• the gluing, when it is part of the assembly, applied to clean and fitted surfaces;
• the final flush fit between steel and handle material.

None of these methods is universal: an assembly with a full tang, an assembly with scales, and a one-piece handle are not worked in the same way. What does not change is the objective: a coherent grip, without unwanted edges under the fingers, and a handle that will last over time. A kitchen knife spends its life between the cutting board and the sink; an approximate flush between scale and tang quickly becomes a moisture trap.

What is adjusted according to the type of knife

Series and unique piece: same requirements, different finishes

The level of finishing varies according to the range. Functional requirements do not. A production knife and a unique piece must both be handled without play, with a properly adjusted mechanism and stable assembly. The difference lies elsewhere: a series requires consistency — ten examples must behave in the same way — whereas a unique piece allows more revisions, details, and time spent on each surface.

For some production models, heat treatment or a preparatory grind can be entrusted to professional partners. Fitting, assembly, revisions, and inspection are still carried out in the workshop. Non-series pieces, on the other hand, are entirely made in the workshop. The Hack N Slash illustrates this logic of series: the same design, several variations, and the same level of mechanical requirement on each piece.

A slight visual uniqueness between two handcrafted pieces is normal: a wood grain, a finish reflection. A poorly adjusted mechanism, however, is not a uniqueness. A beautiful handle draws the eye; it also draws attention to a poorly flush ferrule.

What the user actually feels

These operations remain invisible in a product sheet photo. They are felt in the hand. A well-fitted knife has a consistent opening from the first to the last degree of the motion, a blade that does not move once in position, a grip without surprises, no extraneous movement when pressing on the board.

It is also a behavior that lasts. An assembly under stress eventually shows itself: a handle that wobbles, an axis that loosens, a flush that opens. A properly fitted assembly ages better and can be repaired: the parts have been designed to be adjusted, not to hide a defect.

I do not claim that a handcrafted mechanism is by nature smoother or stronger than an industrial mechanism. I can, however, describe precisely what has been adjusted, checked, and corrected on each knife that leaves here — and that is exactly what you feel when you open it to cut sausage rather than to admire it in a display case.

Check again, before finishing and shipping

The fitting does not stop at the first satisfactory assembly. After the dry assembly come the finishes, and each finish can alter a surface condition or a measurement. The knife is therefore checked again: mechanism, centering, play, flushness. Then come sharpening, cleaning, and a general inspection.

The final inspection of a knife reviews all of these points before shipment. A knife that has play, rubbing, or a functional defect does not go out. It returns to the workbench.

From spare parts to finished knife

Fitting is the step that transforms a batch of correct parts into a usable knife: a mechanism adjusted for its type, no play, a stable assembly, a coherent grip. It is also what explains part of the price of a handcrafted knife — not the material alone, but the time spent adjusting, inspecting, and reworking until everything works.

To see how these principles are applied in practice, the Currently available pieces show the result of this work, ready to join a pocket or a kitchen.