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Drill-Bit.
Patent for improvement to drill-bits. The object of the invention is to provide a bit of the character described which is especially adapted for deep well drilling by the rotary process.
Date:
December 30, 1919
Creator:
Humason, Granville A.; Bierce, Edward B. & Parker, John W.
System:
The Portal to Texas History
Combination Drill Bit and Drill Shank
Patent for "Improvements in Combination Drill-Bits and Drill-Shanks" (lines 6-7) including illustrations.
Date:
December 30, 1919
Creator:
Humason, Granville A.
System:
The Portal to Texas History