I’ve always fancied screws. That such a devilishly cunning device with no moving elements can impart immense force through simple rotation is nothing short of brilliant.
Brilliance was Leonardo da Vinci’s code; he no doubt looked at Archimedes’ water screw and decided to apply the principal more appropriately to making fasteners. In any event, he designed a screw-cutting machine, but it’s not known if he ever built his machine let alone produced any boxes of ten-by-inch screws with it.
It probably says a lot about the Germanic race as a whole that the medieval Princes of Wolfegg saw fit to employ the action of the screw to operate their thumbscrews, head presses and other frightful instruments of torture rather than to make wood screws to repair the great creaking castle doors.
Oh for goodness’ sake!
Another Continental, a Frenchman ingénieuse, Jacques Besson, devised a screw-cutting lathe in 1586, but if early French furniture is any indication of Gallic excellence, it’s of little surprise we’ve heard no more of Monsieur Besson and his screws.
Early screw-cutting lathes seem to have been little more than proofs of concept with the majority of screws (in a world of little screw production) still being produced by smallworkers, often family groups, using crude devices to hold the iron blanks, and files and chisels to cut the threads and head slots. The screws they produced are easily identifiable by their blunt, deep, irregular threads, roughly terminated points and often off-centre head slots.
Roughly shaped shank and blunt, parallel threads.
Irregularly filed, tapered shank and the off-centre slot.
Nonetheless, a few more furtive gentlemen had a stab at mechanising screw-cutting during the successive years, some with more success than others. William Wyatt, from Burton on Trent of all places, patented a screw-cutting machine (Patent No. 751) in 1760 which appears to be the first major advancement capable of true mass-production.
These late eighteenth century machines produced screws with more regular heads, sharp even threads, but the blunt tips remained.
Sharper, more uniform threads with well formed point.
In 1767, thirty six of Wyatt’s machines were installed in an old water-powered mill at Hartshorne near Burton on Trent, “… producing an average of 1,200 gross of screws per week.” Wrote the Reverend Shaw in 1796. “The screw mill employs 59 people, many of them children.” I’ve always thought a childhood spent playing with toys was overrated.
Further advancements by Henry Maudsley resulted in a new screw lathe in 1798 which truly established screw mass-production and widespread adoption of the screw in cabinet-making.
With astonishing prescience, King James II annexed Rhode Island in 1686 (so Mssrs. Abom and Jackson could set up the first North American screw factory there in 1810), screwing the Narragansett and Wampanoag tribes in the process.
Prior to Wyatt’s invention which produced screws with parallel shanks, hand-cut screws might have had tapered or parallel shanks – the gimlet point screw wasn’t patented until 1837 by two more gents born in the U.S.A., Sloat and Springsteen. Their invention also formed the screw heads automatically, producing distinctive concentric marks on the heads.
Nineteenth century gimlet point screw.
Lathe-made swirl marks on screw head.
Examining these key distinctions can assist in dating screws (and ultimately, furniture) although care is required as abuse by slapdash screw drivers – not screwdrivers – and rust can often obscure tell tale marks we might prefer not be present.