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Key to Links for Patent Information
USPTO = U.S. Patent Office .
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on patents related to machinery and tools. A much easier user interface than the
USPTO's for finding information on machinery patents.
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421,218
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Feb. 11, 1890
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Countersink/Counterbore Bit
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Morris Wood |
Chicago, IL |
The innovation here is an auger bit with a hole down the center into which a screw-tipped rod is inserted, which forms the center-point of the auger. The rod is fixed in place with a set screw. This construction allows the tip to be removed for sharpening the auger spurs. As the sharpening gradually reduces the length of the auger, the placement of the screw-tip can be adjusted. In addition, a damaged screw-tip can be replaced for considerably less than the cost of replacing the entire auger bit. This style of auger bit was seen in a 1903 catalog from Morris Wood & Sons of Chicago, makers of countersinks, boring bits and twist drills for woodworkers. |