Wood Screw.
Description:
Patent for a new and improved wood screw. This design "consists of a screw-head having on the underside . . . cutting-edges alternating with flat and deep interspaces or notches, said notches completely filling the circuit of the screw-head and the notches gradually increasing in width and depth from the screw-shank to the crown of the head, thus enabling the cutters to clear themselves" (lines 12-20).
Date:
November 23, 1880
Creator:
Eckford, John
Partner:
UNT Libraries Government Documents Department