US Patent: 3,899
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Single-Twist Auger, Gimlet, &c.
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Patentee:
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William N. Clark (exact or similar names) - Chester, CT |
Manufacturer: |
Not known to have been produced |
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Patent Dates:
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Granted: |
Jan. 31, 1845 |
USPTO (New site tip) Google Patents
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Jeff Joslin (dm)
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Description: |
Patent claim has to do with the inner and upper surfaces of the twist being concave, rather than convex. The purpose is to allow the chips to rise up through the bit more freely, especially an advantage while boring deep holes. |
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