Ron Duncan wears his passion for fine steel on his sleeves. Actually, he wears it under his sleeves, where his skin bears the scars of innumerable burns from hand forging Damascus-steel knives.
A resident of Cairo, Mo., Duncan is one of many craftsmen around the country who specialize in making high-quality knives featuring Damascus steel blades. Notable knife-makers who have influenced and even trained Duncan include Corbin Newcomb of Moberly, Bill Moran of Maryland, Jerry Fisk of Arkansas and the late Jim Mayes, formerly of Auxvasse.
Due to the popularity of inexpensive, mass-produced, commercial-grade knives, Damascus steel craft became what many considered a lost art. However, fine quality never really falls out of fashion, and there's no question that Damascus steel is more durable and holds a razor-sharp edge longer than any other steel. Duncan and his colleagues recognized the demand, and they have been largely responsible for bringing Damascus back into vogue.
Unlike retail grade knives, which are stamped from a sheet of 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. He then forges a blade out of each blank. The craftsman then grinds the forged blade into a finished knife. Afterwards, he heat-treats it, and then tempers it. Finally, he bathes the blade in acid, which etches the beautiful patterns that define Damascus steel.
It takes about 20 hours to complete a single knife, and each one has a distinct look and feel. These qualities make every Damascus knife an heirloom.
A Brief History of Damascus
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, and they represented the most advanced form of weapons-grade metallurgy in existence.
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, and they are extremely valuable and sought after still today. Vikings also made Damascus knives and swords, and their metalwork is considered some of the finest ever created.
Damascus artisans were so protective of their craft that most of them did not train proteges or employ assistants. When a sword maker died, he took his secrets to the grave. In time, the number of Damascus artisans progressively dwindled. By the 1800s, the art was all but extinct. The last place it was used extensively was in the manufacture of shotgun barrels. However, Damascus twist barrels were built for the low pressures generated by the ignition of black powder. When smokeless powder became the standard as a firearms propellant, Damascus was "laid to rust," so to speak.
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 some steel 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.
An avid outdoorsman, Ron Duncan got frustrated with discount store knives while elk hunting in Colorado. He had a brand new hunting knife made by a well-known company, but it dulled well before he'd finished field dressing an elk.
"A good knife should be able to field dress three or four elk without resharpening," Duncan said. "You can do that with the knives I make."
To find the right combination of qualities, Duncan has used steel from an amazing variety of sources. Automotive leaf springs contain good knifemaking steel, but he also loves to use 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.
Standing in the Furnace
There's a hard frost on the ground in Cairo, but it's mid-summer inside Ron Duncan's workshop. The fire in the gas forge is roaring, and soon I have to remove my jacket. Within minutes, sweat breaks out along my forehead and along my collar.
As the inside of the forge approaches 2,300 degrees, Duncan carefully stacks 10 steel wafers to form a rectangular billet. These wafers are alternating layers of high-carbon and high-nickel steel. He uses an arc welder to attach a steel handle to the rectangle. This also immobilizes the wafers, allowing Duncan to control them during the forging process. Then, like a baker stuffing a loaf of bread dough into an oven, Duncan places the billet into the forge. We pour ourselves a cup of coffee and wait. Within minutes, the billet reaches welding temperature, which is about 2,300 degrees. This is the temperature at which steel molecules separate into a semi-liquid state, allowing them to bond. At this point, the 10 layers will be hot enough to forge into one solid billet.
Duncan removes the billet from the heated forge and puts it under a hydraulic press, which squeezes the layers of steel into one homogeneous mass. He creases the middle of the billet after pressing the layers together and expanding them to the right length. This allows Duncan to fold the billet in half. Now, instead of 10 layers, the billet contains 20 layers. After reheating, he'll fold it again to form 40 layers, then 80, then 160, on up to however many Duncan desires.
"The more layers you have, the better it is from both a visual perspective and for strength," Duncan said. "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 as far as 15 feet. The scars on Duncan's arms are souvenirs from years of being splattered by molten flux.
"You can avoid that by wearing burn-resistant clothing," Duncan said, "but you feel how hot it is in here now. Imagine how hot it gets in here in July and August. If it's 90 degrees outside, then it's 120 degrees inside the shop. You can hardly stand it. Sure, you get burned sometimes, but that comes with the territory. You learn to live with it."
When he finally obtains enough layers in his billet, Duncan stops welding and 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 uses a 25-pound trip hammer, along with an old-fashioned anvil and hammer, to pound the billet into the type of knife blade he wants to make.
In a separate workshop wait a fascinating array of belt sanders and grinders. For the next several hours, Duncan will sit in a veritable shower of white-hot sparks as these machines shape the blank into a serviceable blade.
"For most of my work, I use a grinding belt that's two inches wide and 72 inches long," Duncan explained. "I start with a 36-grit belt, which is really coarse, and gradually step down to a 400-grit finish, which is very fine."
When he finishes grinding, Duncan holds a nearly-completed knife blade with a bright, mirror finish. Now, it's time to heat-treat the blade, which he does with an acetylene torch. He reheats the blade to above 1,800 degrees, and then quenches the cutting edge in Canola oil. This heat-treating process hardens the edge, but leaves the rest of the blade softer so it will flex.
If you look at one of his knives that's heat treated, you'll notice a distinct line where the steel changes color. That's called the Harmon line, where the steel goes from hard to soft.
"Unfortunately, the edge is too hard at that point," Duncan said. "I have to draw it back by heating it up to a lower temperature--say 325-450 degrees, depending on the type of steel in the blade--for one to two hours. The amount of time also depends on the type of steel. I repeat this process two or three times."
This process is generically called tempering. More accurately, it is called stress-relieving. That 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, Duncan 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. He fashions handles from a myriad of materials, including burly maple, walnut, antler and horn.
Now we're down to the trim work. Duncan grinds the handle and guard to the desired shape, and then finishes them by hand-sanding. Sometimes he uses a buffing machine to give the guard and pommel a mirror finish.
He then soaks the blade in ferric chloride, a highly corrosive acid, for 30 minutes or more. The acid eats away at 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 jet black. To neutralize the acid, he 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.
The knife is now finished. All that's left is to sharpen it and make a sheath for it. The product is a knife for the ages.