The handmade nails of the period derived much of their holding power from the ability to drive the nail through two surfaces and bend it over on the backside, i.e. But that solution would not work for securing the top on a chest of drawers or table top without either driving a nail through the top from above or clinching it on the top to hold it fast.The same problem arose while trying to affix a lock to the backside of a drawer.For a nail to hold it would have had to be driven through the front of the drawer.
Note the flat spot on the shaft, the irregular threads, blunt tip and the off center slot.
The screw in the center is machine made around 1830.
It has sharp, even threads, a cylindrical shape, blunt end and the slot is still off center.
The screw on the right is a modern gimlet screw, post 1848, with tapered shaft, even threads, pointed tip and centered slot.
ne of the most overlooked and least understood clues in establishing the date and authenticity of older and antique furniture is the story that screws can tell about the history of a piece.
Screws are relative newcomers to the production of furniture primarily because they are so hard to make by hand.
But as the complexity and sophistication of furniture increased in the late 17th century 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.
The screw on the left was handmade in the late 18th century.
C., used a shaft with a surrounding spiral in a tube to lift water, making use of one of the basic tools of physics, the ramp.
In effect a screw is a ramp wrapped around a column.
But how to manufacture that ramp on that column by hand?