Wood Screws: Why do we care?
Wscrews happen to be one of the least understood clues in establishing the date and authenticity of antique furniture — and are especially valuable for dating country and primitive furniture. The stylistic techniques used to date formal furniture such as Chippendale and Hepplewhite simply do not work for American country and primitive furniture and screws can tell a story about the history of a piece.
Wooden screws — screws made from wood — date from antiquity; Metal wood screws for fastening into wood appear to have originated in the 15th century. Screws are relative newcomers to the production of furniture and did not become a common woodworking fastener until more efficient tools were developed around the end of the 18th century.
As the complexity and sophistication of furniture increased and the use of brass hardware, locks and concealed hinges became more popular, there was an obvious need for a fastener that could hold two surfaces together without having to penetrate the back surface of the second piece. Early screws differ significantly from their modern equivalents, both in how they look and how they were produced.
Handmade screws of the 18th century started out much as the handmade nails of
the period did, as square iron nail stock produced in a rolling mill. In the American colonies, these iron rolling mills existed all along the Atlantic coastline, turning out nail stock for the blacksmiths in the growing settlements. Many times, the smith who made the nails occasionally made screws and left us with personal traces of the maker. Lacking a cold hardened steel die with which to cut the threads, the craftsman had to hand-cut it himself using a file. Screws produced by this technique can vary significantly in their shape and the thread pitch. They are most easily identified by the profusion of file marks in many directions over the surface. Also, on the top of the screw, evidence of handwork is abundant. In most cases the head is not perfectly round and is not centered perfectly on the shaft. The hand cut slot is seldom perfectly centered on the off-center head. Due to the individual nuances and variables in the handwork process, no two handmade screws are identical.
The first record of a manufactured screw was in England in 1760. The patent outlined the use of a lathe and a set of metal cutting tools, which were repeatedly run over the shank of the screw blank to cut threads, which facilitated hand production. Many of these screws were flat bottomed, until it was realized that a pointed end worked better as a fastener.
Screws made from about 1812 through the mid-1800s were partially machine made giving the threading a more even appearance, but the heads were still finished with hacksaws to add the groove to fit a screwdriver like those made even earlier, so no two are exactly alike.
Around the time of the Industrial Revolution, about 1860, the method of making nails, screws, hinges, latches, and of milling lumber changed often. Each change is documented, and most are patented. The style of nails changed a dozen times, the hinge changed four times, the screw changed three times, and so did latches and pulls. The methods of working wood also changed during this time. The saw changed, molding styles changed, mortising changed.
Although country furniture does have its regional styles — the French and the Irish built cupboards with bold moldings, raised panels and bright colors, New England cabinetmakers built simple unadorned cupboards painted in dull colors — using styles to determine the construction date of country and primitive furniture is challenging since regional styles remained unchanged for most of the 19th century. Unable to use style, dealers and collectors have turned to the telltale signs left on the furniture itself by tools and by construction methods, including identifying screw types. This system is remarkably accurate to within a ten-year period.
Buyers should be aware that hand finished screws in a piece of furniture may not be the original. One clue is to look at the slot in the head. In the early 1800’s, screws were hammered into their shape by a blacksmith. When there are marks made by a screwdriver turning the screw in a clockwise direction, it would indicate the screw was screwed into the wood by a screwdriver could indicate that the screw was removed. The original screw may have not been replaced.
The introduction in 1848 of the completely machine-made gimlet screw, with a tapered shaft and a pointed tip, marked the beginning of the modern era in screw production. For the first ten years of production, machine made screws were made with no slot in their head. The slot still had to be cut by hand with a hacksaw. Country furniture made with these screws can easily be dated to the ten-year period 18461856.
With the exception of the materials used and the various types of heads, Phillips, Torx, square recess, etc., the basic design of the screw has remained unchanged since the mid19th century.
Philips head screws were introduced in the late 1930’s and so, any furniture that has a Philips head screw will indicate either the piece was made after the late 1930’s, or it is not the original screw.
Examine examples of old screws very carefully and they will provide a valuable clue to their origin and perhaps to the origin of the furniture in which they are found.