Knife making

"For more information, see the Knife article."

Knife Making (also known as knifesmithing) is the process of manufacturing a cutting instrument by any one or a combination of processes: stock removal, forged to shape, welded lamination or investment cast.Typical metals used come from the carbon steel, tool, or stainless steel families. Primitive knives have been made from bronze, brass, iron, obsidian, and flint.

Materials for Blades

Different steels are suited to different applications. It is a tradeoff between hardness, toughness, edge retention, price, corrosion resistance, and achievable sharpness, Also the difficulty of working with the material must be taken into account. Some examples of extremes:
*Obsidian can achieve a nearly molecular edge (high achievable sharpness) and only requires stone age technology to work, but is so brittle that it cannot maintain that sharpness for very long. Also the entire blade is very easy to break by accident.
*The newest powder metallurgy steels can be made very hard, but can quickly wear out abrasives and tooling.
*A blade made from low carbon or mild steel would be cheap in materials cost and cheap to make. A low carbon blade would be very hard to break, but would bend easily and be too soft to hold an edge.

Initial Shaping

Forging

Forge
Anvil
Hydraulic Press In forging, the metal heated to high temperature in Forge and pounded against an Anvil to achieve the shape, often %90 done. Steel can be folded either to form decorative pattern welded steel or to refine raw steel, as the Japanese call it, tamahagane. Grain size should be kept at a minimum and growth is easily occurring in forging.

Blanking

In mass production or well equipped shops blanking can be done. This is done with a number of methods, depending on the thickness and the alloy of steel to be cut. Thinner, low alloy blanks can be stamped from sheet. More difficult, or higher production jobs can be done with cnc water jet cutters, lasers or electron beam cutting. These two lend themselves towards larger custom shops.

Knifemakers will sometimes contract out to a shop with the above capabilities to do blanking. For lower production makers, or lower budgets, other methods must suffice. Knifemakers may use many different methods to profile a blank. These can include hacksaws, files, belt grinders, wheel grinders, oxy-acetylene torches, or any number of other methods depending on budget.

Grinding

Initial grinding

If no power equipment is available, this can be done with files if the piece of steel has not yet been hardened.Grinding wheels, or small belt sanders are usually what a beginner uses.Well equipped makers usually use a large industrial belt grinder, or a belt grinder made specifically for knifemaking.

Heat Treatment

For an in-depth article on this process, see heat treatment.

Blade Finishes

The finish quality of the blade is determined by the Grit of the finishing grind. These can range from a low-shine 150-250 grit finish to a mirror-shine accomplished with a Japanese water-stone, which has an approximate grit of 10,000-12,000. Most high quality manufactured knives have about an 8000 grit finish.

References