Custom knife makers wear their passion for fine steel on their sleeves. Actually, they wear it under their sleeves where their skin bears burn marks from hand forging steel blades.
Arkansas is a repository of native craftsmen and others who came from afar to hone their bladesmithing skills. Notable Arkansas knifemakers include Jimmy Lile, Jerry Fisk and Bob Dozier. Most specialize in certain types of steel. Dozier, for example, is so closely associated with D2 stainless steel that he is known in the industry as Dr. D2. Others create Damascus steel, which is known for durability, versatility and edge-holding ability.
Unlike retail grade knives, which are stamped from medium quality steel, Damascus steel is formed by folding many layers of high quality carbon steel into one block. This block is called a billet. From one billet, a knifemaker can cut several blanks. It takes about 20 hours to complete a knife, and each one has a distinct look and feel.
A Brief History
During the Middle Ages, when European crusaders invaded the Holy Land, they often fared poorly against Saracen cavalrymen swinging thin, light swords so sharp they could slice a man cleanly in two. They were also so flexible that they could bend without breaking. Those swords were made of Damascus steel, an advanced form of metallurgy for that era.
Japanese sword makers also used the Damascus process to make samurai swords. Vintage Damascus samurai swords contained as many as 2,000 layers of steel. Vikings also made Damascus knives and swords, and their metalwork is considered some of the finest ever created.
Hard Steel, Soft Steel
Modern knives are judged by the amount of carbon and other components in their steel. The higher the carbon content, the harder the steel. However, too much carbon makes the steel brittle. Too little carbon, and the steel is too soft to hold an edge. Discount store knives generally are made from low quality stainless steel, or with too little carbon to make a good blade. Also, the carbon content is uniform throughout the blade. Thus, the steel is just as hard on the edge as in the middle and at the top.
Damascus steel, on the other hand, exhibits many different qualities. For example, a good Damascus blade contains different steels with high nickel and high carbon content.
To find the right combination of qualities, bladesmiths use steel from a variety of sources. Automotive leaf springs contain good knifemaking steel, as do large circular saw blades or large bandsaw blades discarded from sawmills. Woven steel cable makes a good knife that will have a unique, highly desirable pattern.
A basic Damascus knife begins with 10 steel wafers that form a rectangular billet. These wafers are alternating layers of high-carbon and high-nickel steel. A smith uses an arc welder to attach a steel handle to the rectangle. This also immobilizes the wafers, allowing the smith to control them during the forging process.
Then the smith stuffs the billet into the forge. When the billet reaches welding temperature -- 2,300 degrees -- steel molecules separate into a semi-liquid state and bond. At this point, the 10 layers are hot enough to forge into one solid billet.
The smith removes the billet from the forge and puts it under a hydraulic press, which squeezes the layers of steel into one homogeneous mass. The smith creases the middle of the billet after pressing the layers together and expanding them to the right length. This allows the smith to fold the billet in half. Now, instead of 10 layers, the billet contains 20 layers. After reheating, the smith will fold it again to form 40 layers, then 80, then 160, on up to however many layers the smith desires.
"The more layers you have, the better it is from both a visual perspective and for strength," said Ron Duncan of Cairo, Mo. "But, you want to see the layers when you etch it, so I stop at around 300-400 layers. People like that because it's pleasing to the eye. Personally, I like my billets to have about 300 layers to get the effect I want."
During repeated weldings, it is important to seal out oxygen. For this, Duncan douses the billet with regular laundry borax (without soap) before putting it back in the forge. This process is called "fluxing." It prevents oxidation from occurring between the layers and ruining the billet.
With each fold, Duncan presses the billet flat, squeezing the layers ever tighter. With each stroke of the press, flux squirts out in all directions. This is where the burn marks come from. Burn resistant clothing offers protection, but a knife shop is so hot that many smiths prefer to work in short sleeves.
When a billet has the desired number of layers, a smith lets the billet cool. He cuts a piece from the billet roughly the size of the knife he wants to make, and then he reheats it in the forge. Once the metal is malleable, he pounds the billet into the type of knife blade he wants to make.
Next comes the laborious process of sanding and grinding. These machines produce a shower of white-hot sparks as they shape the blank into a serviceable blade. A common practice is to start with a coarse, 36-grit belt and gradually step down to a 400-grit belt, which produces a very fine, bright, mirror finish.
Next, the smith heat-treats the blade with an acetylene torch. When the blade temperature exceeds 1,800 degrees, the smith quenches the cutting edge in light oil. This heat-treating process hardens the edge, but leaves the rest of the blade softer so it will flex.
At this stage, a blade exhibits a distinct line where the color changes. That's called the Harmon line, where the steel goes from hard to soft. The edge is too hard at that point, so the smith reheats the blade to 325-450 degrees, depending on the type of steel in the blade, for one to two hours.
This stress-relieving process brings the hardness down to 58 on the Rockwell Scale, where before it was 61 or 62 or higher. It shrinks the grain size of the steel and makes it very fine. That makes the knife a lot tougher. A knife that is only heat treated is very brittle.
After tempering, a smith regrinds the blade with a 400-grit belt to remove hard scale that builds up from the heat-treating process.
After removing the hard scale, he attaches the guard and handle material to the knife.
Then, the smith soaks the blade in ferric chloride, a highly corrosive acid, for 30 minutes or more. The acid etches the high-carbon steel but does little to the high-nickel steel. This exposes the different patterns in the blade, but at first, it turns the blade black. To neutralize the acid, the smith washes it off with water and dishwashing soap. Then, with 1,000-grit sandpaper, he sands the blade by hand. This highlights and brings out the blade's delicate, signature Damascine pattern.
All that's left is trim work. The smith grinds the handle and guard to the desired shape, and then finishes them by hand-sanding. A buffing machine to give the guard and pommel a mirror finish, if desired. He fashions handles from a myriad of materials, including burly maple, walnut, antler and horn.