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US Patent: 21,960
Tap for Cutting Wooden Screws
W. O. Hickok - Harrisburg, PA

USPTO Classifications:
408/214, 408/222, 470/198

Tool Categories:
woodworking tools : hand drills : drill bits


Not known to have been produced

Henry Beader
S. Schriver

Patent Dates:
Granted: Nov. 02, 1858

Patent Pictures:
USPTO pdf tiff
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Claim primarily focuses on the addition of "... a series of minute threads, each of the same pitch as that of the reguar ... screw threads of the tap ..." to the cylindrical projection which guides the bit into the prepared hole. The aim being to ensure reliable and accurate starts for the thread cutting process. He patented a companion screw-box at the same time (21961).

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