One Good Turn: A Natural History of the Screwdriver and the Screw (2 page)

The most unusual hammer I own comes from a hardware market in Mexico City. Made in China, it is a “combination case opener,” that is, a packing-crate opener. Like the specialized shingler’s hammer, which combines a hammer and a hatchet, the case opener incorporates several tools: a hammer, a nail puller, a hatchet, and a crowbar. Mine must have been made in one of Mao’s backyard furnaces, for shortly after I bought it, one of the metal claws broke off as I was pulling nails. Nevertheless, I still have it. While I am unsentimental about most possessions, I have never thrown away a tool.

I have always thought of combination tools as particularly modern gadgets—I am embarrassed to recollect that I once gave my father a screwdriver with a built-in flashlight as a Christmas present. In fact, the combination
tool is ancient. The two oldest woodworking tools are the ax, for felling trees, and the adze—with its blade turned ninety degrees—used for dressing timber. A combination ax-adze was used by the Minoan civilization of Crete, which also invented the double-headed ax. The ax-adze was popular with Roman carpenters. The Romans, who invented forged iron nails, used another dual-purpose tool: the claw hammer. Pulling nails exerts heavy pressure on the handle, which risks being pulled out of its socket, or eye. Medieval English claw hammers sometimes had two metal straps that reinforced the connection to the handle. An American was responsible for the modern form of the claw hammer. In
1840
, a Connecticut blacksmith, inspired by the adze, added a tapered neck that extended down the hammer handle, resulting in the so-called adze-eye hammer, which survives to this day.

Ancient Egyptian woodworkers used wooden pegs instead of nails. They made the holes with a bow drill. The bow drill, probably adapted from a fire-stick, has a cord wrapped around the drill and held taut by a bow. Holding the drill vertically, the carpenter moves the bow back and forth, like a cellist, pressing down on alternate turns. Because the carpenter exerts downward pressure with only one hand—and the cord can easily slip—the bow drill is ineffective for heavy drilling. (Bow drills continued to be used for delicate drilling until the nineteenth
century.) Moreover, since each drilling stroke is followed by an idle return stroke, the bow drill wastes energy. Once again, it was the Romans who found a solution: the auger. The auger has a short wooden cross-handle, attached to a steel shaft whose tip is a spoon-shaped bit. The carpenter, holding the handle with both hands, can apply both great rotational force and heavy downward pressure. A particular variation of the auger, developed in the Middle Ages for drilling deep holes in ships’ timbers, is called a breast auger. It is topped by a broad pad on which the carpenter rested the entire weight of his body.

A medieval workman with his tools, including a carpenter’s brace. Detail from
Bearing the Cross,
part of an altarpiece painted by Meister Franke,
1424
.

The auger is a great advance, but it has one drawback: the bit tends to freeze in the wood between turns. The great breakthrough in drilling tools occurred during the Middle Ages with the invention of the carpenter’s brace. The brace holds the same spoon-shaped bits as an auger, but the handle is shaped in such a way that it is possible—for the first time in history—to drill holes with a continuous rotation. A rounded pad atop the brace enables the carpenter to push down on the bit as he turns with a smooth back-and-forth motion.

One of the earliest representations of a brace is contained in the right-hand panel of an altar triptych painted about
1425
by the Flemish artist Robert Campin and now hanging in the Metropolitan Museum of Art in New York. The subject is Saint Joseph in his workshop. Joseph is making mousetraps (this is an allegorical painting), and he is surrounded by tools—a hammer and nails, a chisel, pincers, a straight saw, and an auger. He is holding a carpenter’s brace and is drilling a hole in a piece of wood that he awkwardly balances on the arm of his chair.

What is striking about the tool that Joseph is holding is that it is identical to the eighteenth-century wooden braces I have seen in collections of American tools, and basically not much different from the brace in my own
toolbox (although mine is steel). Some tools, such as hammers and saws, evolve slowly over centuries; others, such as planes, seemingly spring to life fully formed. The brace seems to have been such a case—it bears no resemblance to the auger or the bow drill. The brace has no antecedents because it incorporates an entirely new scientific principle: the crank. The crank is a mechanical device with a unique characteristic: it changes reciprocal motion—the carpenter’s arm, moving back and forth—into rotary motion—the turning bit. The historian Lynn White Jr. characterized the discovery of the crank as “second in importance only to the wheel itself.”
⁵
The crank made possible not only the carpenter’s brace, but also hand-cranked mills and grinders, as well as a variety of water- and wind-driven machines such as stamping mills and pumps, and eventually steam engines.

There is no material or textual evidence that the crank existed in antiquity—as far as we know, it is a medieval European discovery.
⁶
The oldest representation of a crank is in a fourteenth-century medieval treatise that shows a design for a boat with a manual crank drive that resembles the kind of recreational foot-driven paddle-boat that is a staple of summer-cottage lakes and city parks.
⁷
A Bavarian book on military engineering published in
1405
includes a sketch of a milling machine turned by a hand crank.
⁸
At about the same time,
cranked lecterns (similar to modern dentists’ adjustable tables) were used by scholars to swing books within convenient reading range.
⁹
So, around
1400
, cranks were in the air. Whether the carpenter’s brace came first or was inspired by one of these other gadgets, there is no doubt that this simple tool was the first practical application of the crank on a broad scale. The origin of the name
brace,
incidentally, is obscure. The tool was first called a piercer, for it was used to drill starting holes that were then enlarged with an auger. One historian speculates that
brace
may refer to the metal braces that were sometimes added to reinforce the crank shape.
¹⁰

The carpenter’s brace is a good tool and it definitely belongs to our millennium. But, as far as my essay is concerned, there is a problem: the brace is, well, boring. Despite the importance of the crank, the carpenter’s brace itself never really developed further. The only nonwoodworking application occurred in the sixteenth century, when surgical braces, called trephines, were used to cut out a disk of bone from the skull. Otherwise, the brace seems to have had an uneventful history. It was merely a better way of drilling holes.

—

I have spent a week thinking and reading without making much progress. Since I am embarrassed to admit to David Shipley that I can’t come up with a subject, it’s beginning to look as if I will have to write about the
unexciting carpenter’s brace. This is not going to be an easy assignment; what had seemed like fun is turning into a chore. Dejected, I mention my predicament to my wife, Shirley. She thinks for a moment and answers, “There is one tool that I’ve always had at home. A screwdriver.” I look at her skeptically. “Definitely, a screwdriver,” she says. “Wherever I’ve lived, I’ve always had a screwdriver in the kitchen drawer. Preferably the kind that has several interchangeable heads, or whatever those end pieces are called.” She adds conclusively, “You always need a screwdriver for something.”

I had forgotten the screwdriver. I go back to my standard reference on hand tools, William Louis Goodman’s
History of Woodworking Tools,
published in
1964
. Goodman was a thirty-year veteran of teaching wood shop in an English boys’ school. He was also a tool collector. I have the impression that he was someone who not only knew a lot about the origin of the Saxon adze, but could also give a handy personal demonstration of its proper use.

I look up
screwdriver
in Goodman’s index—nothing. That’s odd. Flipping through the book, I find an entire chapter on the carpenter’s bench, a meditation on the origin of the glue pot, but nothing about screwdrivers. Then a chart catches my eye: “Woodworkers’ Tool Kits at Various Periods.”
¹¹
It lists the times when various carpentry tools were invented and confirms what I already
know—most hand tools originated during the Roman period. The Middle Ages added the carpenter’s brace; the Renaissance, some specialized planes. The next period, “
1600
to
1800
,” saw the invention of the spokeshave, a sort of pulling knife used to make wheel spokes and chair spindles. Finally, in “
1800
to
1962
,” I find the screwdriver. It is one of the last additions to the woodworker’s toolbox.

Usually, my
1949
edition of the
Encyclopaedia Britannica
is informative, but the entry “Screwdriver” is a simple definition—no history. The “Tools” entry does not even mention screwdrivers. I check the on-line
Britannica,
which is more helpful: “The handled screwdriver is shown on the woodworker’s bench after
1800
and appears in inventories of tool kits from that date.”
¹²
At least it isn’t another Roman invention. I’m not convinced that the screwdriver is any more earthshaking than the carpenter’s brace, and it is a laughably simple tool. Still, I am puzzled by its late appearance. It is definitely worth looking into.

I.
Traditional Japanese saws likewise are pulled rather than pushed. With paper-thin blades, they are used chiefly for delicate cabinetwork.

I
START MY SEARCH
for the origins of the screwdriver by consulting the
Oxford English Dictionary.
According to the citation, the first appearance in print of
screwdriver
was in
1812
, in a book titled
Mechanical Exercises.
My university library has an original copy. It is a self-help manual for budding artisans written by a Glaswegian, Peter Nicholson. At the back of the book, in a list of definitions, I find the quote: “Screw Driver: a tool used to turn screws into their places.”
¹
Simple enough. Unfortunately, the author does not include an illustration. Nor does he mention the screwdriver anywhere else in the book; he either thought that the tool was little used—or else he took it for granted.

In the introduction, Nicholson acknowledges his debt to Joseph Moxon, the author of the first systematic account in English of craftsmen’s tools and methods, published more than a hundred years earlier. Moxon, a friend of the diarist Samuel Pepys, was a printer by trade. His London shop, “under the Sign of Atlas in
Warwick Lane,” sold not only books, but also maps, nautical charts, globes, and mathematical instruments. In
1678
, to expand his business, Moxon began publishing how-to-do-it pamphlets for carpenters, bricklayers, and joiners. The booklets appeared monthly and sold for sixpence. In
1693
, he compiled the series into a book. The
238
octavo pages, including eighteen copperplate engravings, was titled
Mechanick Exercises.

The endearing subtitle of Moxon’s book is “The Doctrine of Handy-Works.” “I may safely tell you,” the author advises in the preface, “that these are the
Rules
that every one that will endeavour to perform them must follow; and that by the true observing them, he may, according to his stock of
Ingenuity
and
Diligence,
sooner or later, inure his hand to the
Cunning
or
Craft
of working like a
Handy-Craft.
”
²
Moxon begins his book by discussing smithing, “which comprehends not only the
Black-Smith’s Trade,
but takes in all the trades which use either
Forge
or
File,
from the
Anchor-Smith,
to the
Watch-Maker;
they all working by the same Rules, tho’ not with equal exactness, and all using the same
Tools.
” Moxon describes a screw-pin and a screw-plate, crude taps and dies used to make nuts and bolts to attach strap hinges to wooden doors. The bolts have square heads and are tightened with a wrench, which may be why Moxon does not mention a screwdriver, here or anywhere else in his book.

I keep looking. There are false leads. I come across a reference to an ancient Greek dedicatory epigram that describes the tools of a carpenter and includes not only a plane and a hammer but also “four screwdrivers.”
³
Since the author lived in the third century
B.C.
, this would make the screwdriver ancient after all. I consult a classical scholar at the university. He points out that the Greek word translated as “screwdrivers” really means “tools to make holes,” for the “dowels” that are mentioned in the same line. So, not screwdrivers—bow drills.