US Patent: 2,358,304
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Method of Making Oil Hole Twist Drills
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Patentee:
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Stuart A. Cogsdill (exact or similar names) - Detroit, Wayne County, MI |
Manufacturer: |
Not known to have been produced |
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Patent Dates:
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Applied: |
Dec. 07, 1942 |
Granted: |
Sep. 19, 1944 |
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Joel Havens "Vintage Machinery" entry for Cogsdill Twist Drill Co.
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Description: |
Claim:
In the manufacture of an oil hole twist drill from a cylindrical blank, the steps of forming a pair of longitudinally extending grooves in an exterior surface of said blank, one of said grooves being deeper and narrower than the other and said other of said grooves being disposed equally on, both sides thereof and shaped to form a bead along each side of the first-mentioned groove, and then simultaneously operating upon said beads to displace them toward one another and into contacting and sealing engagement with respect to each other whereby to close the outer side of said first-mentioned groove. |
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