Knife Production

Discover Did You Know

Modern cutting tools have come a long way from the sharpened stones and shells first used centuries ago. Today’s high-end cutlery will last for generations of daily use without undue deterioration if adequately maintained. To successfully describe the features and benefits of high-quality cutlery to your customers, it is essential to thoroughly understand the different materials used and the manufacturing processes in knife production.

How to Choose Quality Cutlery

First, feel and touch it. After all, this purchase is a major investment that should last you a lifetime.

  • Does the blade taper evenly from the handle to the tip and from the back of the blade to the cutting edge?
  • Are the edges smooth with no grooves or gaps between the handle and the blade?
  • Is the knife ergonomically designed?
  • How well balanced is the knife?

Proper balance produces a better, more functional tool. In addition, heft and weight and the blade’s sharpness add safety to the knife by reducing strain and fatigue.

The Making of a Knife

While different manufacturers have their proprietary manufacturing processes, the basic steps are generally the same.

The First Step: The Material

Creating the blade is the first step, and the type and quality of material chosen for it will affect the outcome. Blades are made primarily from steel, but ceramic knives are also growing in popularity. So first, we’ll discuss steel.

The knife’s quality parallels the steel’s quality. Unfortunately, it is not easy to visually determine the quality of the steel used in a particular piece of cutlery. One way you can generally discern the steel’s quality is to give the knife a “ring” test by tapping the blade – flat side down – on a hard surface. If the steel used is soft, the sound emitted will be flat and dead. If the steel is hard, a distinctive ring will emerge.

The main components of steel are iron and carbon, of which the latter increases the steel’s hardness and tensile strength.
The oldest type of steel used, carbon steel, may be hardened to 53 degrees Rockwell (the minimum standard for cutlery). Carbon steel knives, which are susceptible to rusting and staining, may be sharpened with a conventional butcher’s steel. Though they take a wonderful edge, they require a lot of maintenance.

Stainless Steel, which will not rust or stain, creates a blade hardened to 61 degrees Rockwell. Stainless steel that is normally used for making cutlery contains 13 percent chromium, which increases corrosion resistance by forming a protective coating of chromium oxide. Additionally, it improves the metal’s characteristics. Stainless steel blades require a diamond-coated sharpener or a professional knife grinder to be sharpened.

High-carbon no-stain steel is a composite of the two materials and has a hardness that varies according to the amount of each material in the mix. Knives made of high-carbon, no-stain steel are easy to resharpen. The steel components are selected to ensure superior cutting performance, flexibility, no-stain properties, and ease of sharpening. The more carbon in the steel, the higher the knife quality since it provides a better, more durable edge and offers superior cutting capabilities. The makeup of many manufacturers’ high-carbon stainless steel is specifically designed to incorporate edge retention, stain resistance, flexibility, and toughness.
Ceramics are another material used to produce high-quality cutlery. Of all ceramics, zirconium oxide has the highest strength and toughness at room temperature. Ceramic cutlery is less subject to rust and more wear-resistant than conventional metals. The material, second in hardness only to diamonds, was initially developed for industrial cutting applications. Ceramic cutlery holds its edge longer than a steel knife, lasting months, perhaps years, before needing sharpening. Ceramic is also impervious to food acids that tend to discolour some steel products and will not brown fruits or vegetables. Ceramic knives are easy to clean and very lightweight.

Contrary to what many believe, ceramic knives will not shatter if dropped. However, any knife that falls on a hard surface can be damaged if it lands at a certain angle. Ceramic knives are strong enough for everyday cutting; however, they are less flexible, and for that reason, should not be used for cutting bones, prying, or flexing. Ceramic knives are ideal for slicing and dicing boneless meats, fruits, and vegetables.

To manufacture a ceramic knife, ceramic powder is moulded into blade blanks using high-pressure presses. Special binders in the powder allow the blanks to retain their shape before they are fired. The firing process requires several days and occurs at temperatures over 1,000 degrees Celsius. The resulting “blade” is then ground on a diamond wheel and polished to form the final shape and the edge.

Generally, ceramic blades are white, but a more advanced ceramic blade that is moulded and fired simultaneously is also manufactured. Because a carbon mould is used, the edge is stained black and more resistant to damage than the “white” ceramic blade.

Step Two: Shaping the Knife

The material alone does not ensure a good-quality edge. Instead, workmanship and the blade’s design play critical roles in determining the knife’s quality. With steel knives, the method used to create the knife and the hardening, tempering, and grinding processes will all affect the outcome.

The next factor that contributes to the knife’s quality is its shape. The two most frequently used methods of manufacturing a knife are stamping and forging. In the former, cut metal sheets are stamped with a die to create the blade’s shape. A more modern method that offers similar results to stamping is the use of lasers. Laser techniques can produce an exact, consistently finished shape and edge.

During the forging process, a cylindrical bar of steel is formed to achieve the desired shape. Then, in a process often called hot-drop forging, the shape is created by using a drop hammer. The art and craft of forging impart desirable characteristics to steel; among them, the fine, tiny grains that comprise the knife’s structure.

In a newer process called precision forging, the steel blank is heated via electricity at the centre point while intense pressure is applied to both ends of the blank. When a molten bubble forms at the centre, the heated blank is placed into a controlled forging hammer that produces far more pounds of pressure per square inch than the drop hammer method.

The forging process involves heating and cooling the steel, which breaks the steel’s crystalline structure into smaller particles, resulting in a tougher, more robust blade. With a stamped blade or with one formed using lasers, the essence of the metal is not changing during the process.

Step Three: Hardening and Tempering the Metal

Once stamped or forged, the pieces undergo hardening and tempering processes. The steel’s heating and cooling often referred to as quenching, increases its hardness and generally improves its mechanical characteristics.

The forged or stamped metal is heated in a controlled electric furnace to an exact temperature and then quenched in the hardening process. At this point, the steel is tough but also brittle.

To reduce the brittleness and bring the metal to the desired degree of flexibility and hardness, the knife undergoes a tempering process in which the steel is reheated to a lower temperature, soaked at that temperature, and again quenched. Tempering relieves the internal stresses created in the materials by quenching and improves hardness.

Step Four: Grinding the Blade

Following the tempering process, grinding helps determine the knife’s final shape. Grinding may be done either by hand or with automated equipment. Grinding and honing the blade is a skilled art and a significant factor that distinguishes one knife type from another. The blade’s shape also affects the edge’s strength and sharpness. The ideal knife has a blade ground down to produce a razor-thin edge that remains strong enough to resist damage.

Rough sharpening is accomplished primarily by using grinding wheels that help define the knife’s shape. It entails shaping its back, creating the shank to which the handle is attached, and matching the sides to enable a perfect final sharpening.

Different grinders are used in all sharpening phases. During the process, the blades are constantly cooled to prevent them from overheating, which could decrease the blade’s hardness or affect the steel’s ability to resist corrosion.

The taper of the blade is critical to its design. View a knife from the handle to the tip of the blade. The blade should taper from thick at the handle to thin at the point. It should also taper from the blade’s spine to its edge. The blade’s design and geometry determine whether it will cut uniformly when appropriately tapered.

The three general types of edges are: Concave, flat, and convex. Any of these configurations may be ground to a fine cutting edge.

The weakest of the three is the concave or hollow ground edge. An open ground blade has a concave profile instead of a uniform taper from back to edge across its width. Though it gives the impression of being sharp, it fails quickly as little metal is behind the edge to support it. A hollow-ground knife has a fragile edge, dulls very quickly, and is difficult to sharpen. Typically, higher-end cutlery manufacturers do not produce hollow ground knives.

Flat edge knives, which come abruptly, have unstable, sensitive cutting edges that chip easily.

Taper ground knives possess what is often referred to as convex edges since they are shaped like an arch. As a result, they offer good support to the cutting edge, are easily sharpened, and have a long-lasting edge – an ideal geometry. Several sharpening stages are required to achieve this shape, but the result is a sharper, more durable edge that tends to last two to three times longer.

The bolster’s shape is also essential. Formed during the forging process, the bolster is the area between the handle and the blade that gives the knife proper balance and weight and prevents the hand from slipping over the cutting edge.

Some manufacturers taper the bolster to the edge so that the entire blade may be used, including the knife’s heel. If the bolster’s thickness extends to the blade’s edge, it can’t be sharpened. A tapered bolster allows the user to sharpen the blade’s entire length, which is particularly important on chef’s knives.

A knife’s balance is one of the most misunderstood components of knife quality. Consumers typically pick up knives, place their fingers beneath the bolsters, and believe the knives are properly balanced if they balance with a slight bounce. However, each knife must be balanced differently.

The bounce will be around the bolster for the chef’s knife, but for a boning knife, the balance should be near the handle’s middle. The balance point of a paring knife should be towards the bolster since the user will most likely extend their fingers along the top of the blade when using it.

It is important to visualize how you would hold a knife when using it. The balance point should be located beneath your working fingers.

A knife’s tang acts as a counterbalancing point. A larger, longer, heavier knife will require a more extended tang to counterbalance the blade and serve as a balancing point.

Step Five: Creating The Handle

The method of attaching the blade to the handle varies from the traditional two- or three-rivet style to a state-of-the-art binding process. A superior handle should feel comfortable and secure and can be composed of wood, stainless steel, polypropylene, or a variety of composite materials. Consumers generally make handle choices based on comfort and design. For instance, wood can offer an elegant look, while polypropylene is impact resistant, breakproof, and hygienic.

Fine cutlery should never be placed in a dishwasher where it could strike against other cutlery or ceramic pieces, resulting in a dulling of the fine edge.

The Knife’s Parts

Blade. The tip or point of the cutting blade is used for cutting small vegetables and decorative work. The heel is the cutting blade’s back end and the blade’s strongest part. The blade’s back or top edge gives the knife strength and works with the cutting edge to perform with ease.

The Cutting Edge is the knife’s most crucial part. A superior cutting edge contains microscopic teeth. The smaller the teeth, the sharper the blade will be. Likewise, a denser molecular structure provides a finer cutting edge.

Handle. The tang is the end of the blade that extends into the handle and gives the knife strength and balance. The tang may be complete (extending through the entire handle) or partial. The metal rivets should be brass or nickel and firmly attach the tang to the handle. Knife handles are made of a variety of different materials.

A superior knife handle should have an all-around smooth finish and feel comfortable and secure.

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