One Good Turn: A Natural History of the Screwdriver and the Screw

Epigraph

Chapter One:
The Carpenter’s Toolbox

Chapter Two:
Turnscrews

Chapter Three:
Lock, Stock, and Barrel

Chapter Four:
The Biggest Little Invention

Chapter Five:
Delicate Adjustments

Chapter Six:
Mechanical Bent

Chapter Seven:
Father of the Screw

GLOSSARY OF TOOLS

ACKNOWLEDGMENTS

ABOUT WITOLD RYBCZYNSKI

NOTES

TEXT ILLUSTRATION SOURCES

INDEX

to Shirley

Heurēka! [I’ve found it!]

—A
RCHIMEDES

T
HIS ALL STARTS
with a telephone call from David Shipley, an editor at the
New York Times.
Would I write an article for a special millennium issue of the Sunday magazine? he asks. The end of the millennium is on many magazine editors’ minds, and I have had a number of such requests. Shipley explains that the theme of the issue is The Best of the Millennium. That sounds interesting. “What do you want me to write about?” I ask.

“We’re hoping that you can write a short essay about the best tool,” he answers.

I am a bit let down.
The best tool
is hardly as weighty a subject as
the best architect
or
the best city,
topics I could really sink my teeth into. Still, I have been working on a long biography and would welcome a break. Writing about the best tool of the millennium might even be fun.

While David Shipley is speaking, I compose the essay in my head. There is so much to choose from: paper clips, fountain pens, eyeglasses. I have recently
seen a portrait in the Pennsylvania Academy of the Fine Arts of Benjamin Franklin wearing round spectacles, a reminder that Franklin was the inventor of the bifocal. Yet eyeglasses are much older than the eighteenth century. The first reference to eyeglasses is in a sermon given by a Dominican friar in Florence in
1306
. He mentions that eyeglasses were invented twenty years earlier, and that he has even spoken with the inventor, although he neglects to give his name.
¹
Medieval eyeglasses were only for farsighted people and were used for reading and writing. They were the first practical application of the new science of optics, paving the way for such far-reaching inventions as the telescope and the microscope. A key influence on literacy, astronomy, and biology, eyeglasses surely qualify as “the best tool of the millennium.” This is going to be easy.

However, when I mention my idea to David, it becomes clear that he has something else in mind. He means
tool
in the literal sense—a handsaw or a hammer. So, not eyeglasses. He must hear the disappointment in my voice, and he points out that I once wrote a book about building my own house. That might make a good starting point, he suggests helpfully. All right, I say, I’ll think about it.

—

In my case, “building my own house” meant actually building it. My wife and I, with the occasional help of
friends, mixed concrete, sawed wood, plastered walls, and installed plumbing. We did everything ourselves except the electrical wiring. Ever since my boyhood experiences with recalcitrant train sets, I have been thwarted by electricity. Despite my father’s patient explanations—he was an electrical engineer—and a college physics course, I never grasped the relationship between voltage, current, and resistance. Electricity, in fact, was a problem in our house-building project—there was none. We were building on a rural site about eight hundred feet from the road, and although we planned to bring in power, initially we could not afford the cost of a temporary line. Renting a gas-powered generator would be expensive, too—and noisy. I decided to build the framing and exterior of the house by hand. Once the basic structure was finished, which promised to take a year or two, we would bring in a line and hire a professional to install the electrical wiring.

Does one of my carpenter’s tools qualify as the millennium’s best? I discount power tools. I had used a portable circular saw, a drill, and a sander for finishing and cabinetwork, but these are chiefly laborsaving devices. Not that productivity isn’t important. Ken Kern, the author of
The Owner-Built Home,
estimates that cutting all the two-by-fours for the frame of a small house would take seven full days using a handsaw, and only thirty minutes using a power saw.
²
I appreciate the ease of
cutting wood with power tools, but the result, while more quickly arrived at, is no different than if I use a handsaw. In any case, I enjoy working with my hands. One of the rewards of building something yourself—a house or a bookshelf—is the pleasure of using tools. Hand tools are true extensions of the human body, for they have evolved over centuries of trial and error. Power tools are more convenient, of course, but they lack precisely that sense of refinement. No doubt, if I spent my life hammering nails, I would feel differently about the virtues of a nail gun, say. Yet increasing the productivity of carpenters does not seem to me in the same category as the invention of entirely new devices such as eyeglasses.

That leaves my box of hand tools. The tools required for the construction of a small wood-frame house fall roughly into four categories: measurement, cutting and shaping, hammering, and drilling. My measuring tools include a try square, a bevel, a chalk line, a plumb bob, a spirit level, and a tape measure. A little reading informs me that almost all these tools predate our millennium; indeed, most predate the
first
millennium of the Christian age. A Roman builder, or
mensor aedificorum,
was familiar with the try square, the plumb line, and the chalk line—all tools that were developed by the ancient Egyptians.
³
The level, or
libella,
also an Egyptian invention, consisted of a wood frame resembling the letter A,
with a plumb bob suspended from the apex. To level, the string was lined up with a mark in the center of the crossbar. Not as compact as my spirit level, perhaps, but obviously just as serviceable since A-levels continued to be used until the mid-
1800
s. The spirit level, with its sealed tube containing an air bubble floating in alcohol, was invented in the mid-
1600
s. It was first exclusively a surveying instrument—it took another two hundred years to find its way into the carpenter’s toolbox. For measuring length, the Roman
mensor
used a
regula,
or a wooden stick divided into feet, palms, twelfths or
unciae
(whence our inches), and
digiti
or finger widths. I have a yardstick, too, but most of my measuring is done with a retractable steel tape. That, at least, would impress my Roman counterpart, whose only compact measuring device was a one-foot bronze folding rule. Oak yardsticks were used in the Middle Ages, and folding rules, in ivory, brass, or boxwood, reappeared in the eighteenth century. I can’t find the origins of the tape measure, but I would guess that it was developed sometime in the late
1800
s. I would be lost without my twenty-five-foot retractable tape measure, but it does not seem to me to qualify as the best tool of the millennium.

I own several saws. The handsaw, too, is an ancient tool: archaeologists have found metal-toothed Egyptian saws dating back to
1500
B.C.
They have broad blades, some as long as twenty inches, curved wooden handles,
and irregular teeth. The blades are copper, a soft metal. To keep the blade from buckling, the Egyptian saw was pulled—not pushed. Pulling is less effective than pushing, since the carpenter cannot bear down on the cutting stroke, and sawing wood must have been a slow and laborious process.
^I
The Romans made two important improvements. They used iron for the blades, which made them stiffer, and they set the teeth of the saw to project alternatively right and left, which had the effect of making the saw-cut—or kerf—slightly wider than the blade, allowing smooth movement.

The Romans also invented the stiffened backsaw, whose blade is reinforced at the top. This prevents straight-through cuts, but the tool is useful for cabinetwork, especially when used in combination with a miter box. The most ingenious Roman addition to cutting tools is the frame saw. A relatively inexpensive narrow blade is held in a wooden frame and is kept taut by tightening a cord. Wooden frame saws worked so well that they remained the most common type of saw well into the nineteenth century (the principle of the frame saw survives in the modern hacksaw). In the mid–seventeenth century, a new type of saw was introduced in Holland
and England. It had a broad, unstayed blade and a wooden pistol-grip handle. The rigid blade, originally made by rolling steel strips, makes a more accurate cut than a frame saw, and there is no frame to interfere with deep cuts. This effective tool became the basic modern handsaw. My workhorse is a twenty-six-inch Disston crosscut handsaw, with a skew-back blade, first introduced in
1874
by Henry Disston, a Philadelphia saw-maker. The open handsaw is a definite contender for best tool, but while it is certainly an elegant solution to an old problem, I think that David expects something a little more momentous.

The chief shaping device of the carpenter is the plane. The box plane is nothing more than a holder for a chisel blade, but it marks an important moment in the evolution of hand tools. Unlike an adze or a chisel, which depend on the skill of the craftsman, the effectiveness of a plane is built-in; that is, the carpenter does not need to control the blade, he provides only the motive force. One historian has called the plane “the most important advance in the history of woodworking tools.”
⁴
That makes it sound like a worthy candidate for best tool of the millennium. Unfortunately, I find that the plane, too, is a Roman invention.

Chisels have more ancient origins. Bronze Age carpenters used chisels with both integral handles and socketed wooden handles in house and furniture construction.
The first mallets, which resembled bowling pins, were pounded across the grain and had a short working life. Eventually, a handle was fitted to a separate head, whose harder end-grain made a more durable hammering surface. Heavy, long-handled mallets are called mauls. Eighteenth-century carpenters used a huge maul, known as the Commander, to drive together the joints of timber-framed houses and barns. The Commander has a head six inches in diameter and a foot long. I didn’t have anything that big, but I did use a steel sledgehammer to coax stubborn joists and studs into place.