On the Edge : The New Stone Age: Sharp and Easy

The cutting edge of a kitchen knife is one-third as thick as a human hair, but if the metal is well tempered and the edge is treated with care, it can remain sharp for a remarkably long time. Some things are hard on an edge: scraping down your plastic cutting board, chopping through bone, dropping your knife into the sink, using your chef’s knife instead of a bread-slicing knife to slice crusty bread. Fortunately, stroking a sharp edge against a ceramic stick every once in a while keeps a knife in working shape for weeks on end.

However, ceramic sticks and butcher’s steels can’t sharpen a dull knife. They can only maintain an already sharp one, and there comes a time when a sharp knife gets dull.

There are many ways to sharpen a kitchen knife. You can buy a diamond stick or a plastic stone encrusted with diamond dust, for instance. But though they give you something that may feel like sharpness, it’s actually an almost serrated edge that tears rather than slices.

The grinding wheel is perhaps the most obvious method, but grinding wheels, like most power-driven sharpeners, eat knives up. The steel simply disappears over a relatively short period of time, which is something to consider when you pay $75 and up for a forged-steel chef’s knife.

And too much depends on the skill of the grinder. Can he maintain the perfect angle between blade edge and rapidly spinning stone surface to achieve the perfect state of sharpened grace? And can he somehow prevent the edge of the blade from heating up in the process, thus losing its temper and becoming soft and weak?

Sharpening stones provide another popular method of sharpening. There are natural stones of varying degrees of hardness and grit, and there are man-made stones that accomplish much the same. Some stones demand oil, others water, to float away the fine metal shavings coming off the edge of the knife with each stroke of blade across stone.

However, attaining a truly sharp edge on a stone requires consummate skill. The blade is held at 20 degrees to the surface of the stone and stroked across in one direction, flipped, then stroked back the other way. Any wavering--lowering the edge to 18 degrees, say, or raising it to 21 degrees--produces an edge that will be too sharp in some spots (where it will quickly weaken and lose its sharpness) and not sharp enough in others.

It is possible to strike a compromise and achieve adequate results with hand sharpening, but only after hands-on instruction (shops that sell expensive woodworking tools tend to offer classes in tool-sharpening technique) and then another 100 hours or so of practice, depending on your hand/eye coordination. Like most simple things, there is nothing easy about it.

What’s a cook to do? Some rely on the Chef’s Choice knife sharpener, a machine-driven set of sharpening stones that can deliver a sharp knife--but only after you carefully read the instructions and then practice with blade after blade. While the angle of blade to stone is pre-set, pulling the blade through the rapidly moving stones with nary a wobble is next to impossible, and each wobble reduces the end result.

Also, the machine grinds a hole in the edge just in front of the heel--the part of the blade closest to the handle. The classic French chef’s knife is meant to rock from tip to heel on a cutting board--grinding a dip in front of the heel defeats the rock. After using the Chef’s Choice for a year, I had all my cutlery ground back into shape and returned the machine to its box.

Now I take my knives to Scott Nighbor, who hand-sharpens knives for many of Seattle’s restaurants, bakeries and supermarkets. He averages 500 blades a week. His sharpening tool requires minimum effort and no electrical power; it removes only microscopic amounts of steel from a blade; it will not overheat an edge; it will not hollow the profile of a blade. It even will correct dips and bellies in a knife edge. The tool is called the Edge Pro. With it, given a modest amount of practice, anyone can take a dull knife and put a perfect edge on the blade.

The device (patent pending) was invented over the course of the last seven years by Ben Dale in his Seattle garage. Knife-sharpening devices are not new; in the patent category “Abrasives; Sharpening Devices; Clamping” there are patents that go back to the 1880s. But in the patent category “Abrasives; Sharpening Devices; Non-Clamping,” Dale’s invention is the only entry.

“It’s the clamping in place of the knife blade that limits those other tools,” Dale says. “You are constantly clamping and un-clamping the blade while you sharpen. And that makes for an inconsistent edge.”

Dale grew up in Cleveland, Ohio. His father, a draftsman, architect, builder and teacher, taught Ben how to sharpen his pocket knife when Ben was 10, and Dale gradually learned to sharpen all the other tools in his father’s wood-working shop. “Some people are into knives,” says Dale. “Like my brother. He collects knives. I’m into sharpening, and could care less about knives in and of themselves.”

One day Dale crossed paths with Jon Rowley, a seafood consultant to the food industry, who knew the value of a hand-sharpened knife. “It never fails to surprise me,” says Rowley, “but most chefs simply have no idea what a sharp knife is or how to sharpen one or how to maintain a good edge. I see that all over the country.”

Rowley told Dale he would generate as much restaurant knife-sharpening work as Dale could handle. “Within two months,” says Dale, “I had a full-time job. And it became immediately apparent that I was going to have to come up with a mechanical way to sharpen knives. It was just too labor-intensive otherwise, hand sharpening with stones.”

Dale’s path to the Edge Pro started the day he positioned a knife blade against the edge of a table, took stone in hand and pushed the stone against the blade. Normally one is inclined to set the stone on the table and move the knife against the stone.

In a moment, Dale had reduced by half the effort of his work. The trick, however, was how to hold the stone and how to push the stone across the edge of the knife and not cut fingers or knuckles while maintaining the consummate angle. In the perfected Edge Pro, the knife blade is rested on and moved across a small stage, and the stone, mounted on a metal rod, is gently pumped by hand at a pre-determined angle across the edge.

The jewel around which the whole machine revolves, however, is the sharpening stone. There are three, maybe four grinding-wheel manufacturers in the United States. It was Dale’s great fortune that one of them, Pacific Grinding Wheel, was nearby in Marysville, just north of Seattle, and that it happened to manufacture man-made abrasives in thin strips one half inch wide and six inches long, the perfect size for the Edge Pro, as Dale envisioned his device.

Dale took an early version of his sharpening machine to the offices of Pacific Grinding Wheel to explain what he was looking for. He set it up on a desk and began demonstrating how it worked. Soon he had attracted a small crowd that included the president of the company. They were all captivated, which is often the case when Dale demonstrates his machine. Dale and Pacific Grinding Wheel spent five years of trial and error before coming up with the perfect recipe for the strips of sharpening stone Dale uses with the Edge Pro.

Here’s how it works: The long arm to which the sharpening stone is attached glides through a pivot mounted at the back of the stage, marked with seven height adjustments in two-degree increments. The one marked in red is 20 degrees, an angle appropriate to the majority of kitchen knives. The other settings allow for re-shaping a badly damaged blade, or for sharpening cleavers (steep edge) or serrated bread knives (nearly flat edge).

Holding the knife in place against the stage, one slowly pumps the sharpening arm across the exposed edge, gradually moving the blade past the stone from butt to tip. Once one side has been worked, the knife is flipped over. After an hour of practice, sharpening a knife becomes a rhythmic exercise lasting two or three minutes.

However, the device that put sharp knives into Seattle restaurants did the home cook little good. The Edge Pro is an industrial tool, intended for businesses that need to keep a lot of cutlery razor-sharp all the time. It costs $195, and few home cooks are interested enough to pay that much.

“It’s why I have come up with this,” Dale says, slapping a stripped-down version of the Edge Pro onto his counter. Instead of an industrial suction-cup base, it has four short legs that pre-set the angle of the stage against which the knife rests. Dale has combined the medium grit (for reshaping a worn knife) and the fine grit (for finishing) into one stone and reduced the seven possible settings for the sharpening arm to two, pre-set for sport knives, kitchen knives, thin-bladed knives and bread knives. A short card, rather than an instruction book and a 20-minute video, explains how it works. It sells for $125, or about what you would pay for a good chef’s knife and boning knife--which you would then need to sharpen.

For information, write to Edge Pro at 425 Federal Ave . East, No. A, Seattle, Wash. 98102.