SCREW (ante). The common screw indispensable for carpentry, fitted with a coarse thread for insertion in wood. is called • the wood-screw. Machine screws, or otherwise fine-thread screws, are used in metals. Screws were little known or used before 1S36, being rudely made by hand with imperfect tools. The head was forged or swedged up by a blacksmith; the thread and nick'were formed by the use of hand dies and hack 'screws. In 1836 American ingenuity was directed to the subject, and the old hand tools were associated in machines ]caving the capacity of imparting to each tool its proper motion. The swedge hammer became the heading machine, receiving the end of a coil of wire and regularly cutting the required length for a blank, which then received such a blow as to "set up" one end of the wire to form the head—the operation continuing automatically until the whole coil was made into blanks. These blanks were then handled individually and presented to organized machines, first for shaving the head, then for nicking, and lastly for cutting the thread. The above constitutes the second era in this manufacture; and such machinery, partly automatic, was all that was in use before 1846. Then a third era ensued, and an entire revolution was effected by consti tuting the machines entirely automatic. The blanks are by this system supplied in mass by the operator, the machine separating and handling each blank respectively as the nature of the operation demands, and producing with wonderful rapidity, regularity, and perfection. Chief among the inventors and constructors of this machinery was
gen. Thomas W. Harvey (b. Vt., 1703; d. 1834), widely known for inventive genius in many directions. After him, perfecting and developing, were Sloan, Whipple, Rogers, and others; while the leading mind that organized this intricate business into probably the most successful manufacturing interest in this country was the late William G. Auge11 of Providence, R. I., president of the American screw company. Gen. Harvey was the first inventor of the partially automatic and of the entirely automatic machines. It is noticeable that though he produced gimlet-pointed screws in 1836, it was not till 1846 that any considerable market was found for them. His son, Hayward A. Harvey of Orange, N. J., likewise a skillful inventor in many departments, has made important improvements in the automatic machines, and this American invention is now in use throughout the world wherever screws are made. It is estimated that the consumption of screws throughout the world is not far from 100,000 gross per day—about 100 tons; and about 500 tons of iron are required for the daily production of machine and wood screws.