Sunday, November 3, 2019

The Magic of Steel

Samurai swordmaking

About a dozen years ago, I tried to by a steel rod that I could use in my karate training as a bo staff. This karate weapon is like the ancient quarterstaff that Robin Hood and his forest band used, but much faster and in greater combinations of moves. Even though the word “bo” means wood, I already had staffs made of fiberglass and aluminum. I figured a weapon made of solid steel would be unbreakable and invincible. So I looked up a steel fabricator online, called them, and tried to place my order.

“What are your specifications?” the polite woman on the sales desk asked me.

“Oh, I want a rod about six feet long and half an inch to an inch in diameter,” I said.

“You don’t understand,” she said. “What are your specifications for the steel?”

Ah! Well. Um … I did know what she was talking about. Any aficionado of pocket knives who peruses the catalogs knows a bit about Rockwell hardness, edge holding capability, rust resistance, and so forth. But what did I want in a staff?

When I was growing up and became interested in knives as both tools and weapons, as well as kitchen utensils, I asked my father—a mechanical engineer who had to be familiar with the properties of various metals—why we didn’t have stainless steel pocket knives. He said that stainless steel was too soft, with a consistency more like stiff taffy, and it could not be ground to take and hold an edge. Nowadays, however, through the work of chemists and steelmakers, we have stainless blades that are as strong as carbon steel, just as good at edge holding, and yet rust free.

In the end, I asked the steel fabricator for a rod of the most “vanilla” metal they had, middle of the road on all specification, except for stainless. They sent me two in the order, and I still have them. But just unpacking the things, I knew I had made a mistake. A six-foot rod of one-inch diameter weighs about thirteen pounds—far too heavy to swing at the speeds of any bo kata and still hold onto. One slip and it would go flying across the room. Still, the experience of purchasing a steel bo had been instructive.

I have long thought it a shame that this country buys most of its steel from China, Japan, and even India. The company called “U.S. Steel” used to be one of the powerhouses of our country’s industry. Steel is the metal of civilization. It’s what we use to build bridges and skyscrapers. It’s the rebar in every concrete structure. It’s the main ingredient in our automobiles, still ahead of aluminum, plastic, and carbon fiber. That we apparently don’t make it anymore, that we rely on overseas, practically Third World countries to supply our steel is a shame.

But it’s not that we don’t make steel in this country. We just don’t make large volumes of non-specific steel for I-beams, rebar, and other general utility purposes. We let the Japanese, the Chinese, or whoever else wants to build a plain old steel mill do that. Instead—as my father knew back in the 1960s and ’70s—we are the world’s leader in specialty steels, metals with specific qualities of hardness, ductility, flexibility, compression strength, rust resistance, and other measures of performance that are dictated by the composition of metal additives in the steel, its carbon content, its treatment, and its finishing.

For example, ball bearings must be extremely hard steel, because they work under the pressure of weight loads, but that kind of steel can be fairly brittle. Tool steel, the sort that goes into drill bits and chisels, must be extremely durable but also shock resistant, because they may be used to cut and shape other metals, including lesser steels. A knife blade has to be durable to stand up to shocks, hard enough to hold an edge, but also ideally resistant to rust in daily use and just sitting in your pocket, where it becomes subject to the moisture surrounding your body.

So when we speak of steel anymore, think of chocolate. The most popular brand in this country, the kind you get out of vending machines—the kind that’s made in great bubbling vats, distributed in boxcar lots, and sold everywhere—is Hershey’s. It’s not bad chocolate, as far as milk chocolate goes. But it’s not special. And it does have a sort of grittiness and leave an oily feeling in the mouth that children don’t mind but that connoisseurs care about. This is bulk chocolate—not the kind they use in making truffles or gift boxes with assorted flavors and fillings. If you want something special, with a particular texture, flavor, cacao content, and so on, you go to a premium chocolatier. The Swiss make fine chocolates for the discriminating baker and the customer’s palette; they let the U.S. pour out vats of Hershey’s milk chocolate.

The Swiss are to chocolate what America has become to steel: the experts in taste and quality.

Being a karate buff and an admirer of oriental martial arts, I used to think that the highest quality of steel—the magical stuff that can cut through anything, hold an edge forever, and never be bent or broken—was found in the samurai sword. We’re not talking about the swords that the Empire turned out by the carload for junior officers at the end of the war, usually cut and hammered from truck leaf springs. No, I’m talking about the ancient art of the sword as practiced by Japanese smiths for centuries—the kind that The Bride sought from Hattori Hanzo in the Kill Bill movies.

The Japanese have made samurai swords for hundreds of years. They work and fold, work and fold the steel, over and over again, to give it strength. They make a certain kind of steel with toughness and flexibility for the back of the blade, and another kind that can be ground sharp and stay sharp for the steel along the edge. These two are then put together: the edge steel in a groove that has been shaped into an ingot of the back steel. The combined blade is then pounded into shape while red hot to weld the steels together, then plunged into water or oil to temper them. The different steels react differently to the sudden temperature change, with the blade steel extending and the back steel contracting at different rates. This bends the blade backward and gives the sword its characteristic curve.

Layering the steel to give it strength, which the Arab and Spanish steelmakers did with Damascus steel, is an old trick.1 But it is only really needed when working with low quality steel that contains a lot of impurities. The Japanese swordmaking artisans would smelt a large lump of steel for just one or two blades in a backyard kiln made of bricks and fired with charcoal. It’s a creative and humanistic approach, requiring great knowledge and the skills acquired through centuries of trial and error and passed down from master to pupil. But the process lacks the precise, scientific control of a modern blast furnace. So these artisans had to layer their steel to drive out the impurities with repeated hammering and to give the steel the strength of many welded bands. A modern steelmaker only makes Damascus steel for show now, not for any inherently superior strength.

Steel has almost magical properties of strength, hardness, durability, and now resistance to corrosion and other specifications. These qualities have made it the favorite of tool makers and armorers over the centuries and to builders and engine makers in the last two hundred years. It was even chosen as his party name by a world leader, Stalin. But anymore, when you think of steel, think of chocolate.

1. It was the Arabs of Damascus, in ancient Syria, who are supposed to have invented this work-and-fold technique of forging, and so they gave this particular kind of patterned steel its name. The Moors brought the technique into Spain, which was also known for its fine steel blades. Tradition says the Damascus steelmakers didn’t temper their red hot blades in water or oil but instead plunged them into the bodies of slaves, to temper them in blood. But that is probably a myth.

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