Rotary Boring-Drill.
Description:
Patent for improvements in rotary boring drills. The invention provides a fluted drill collar for a drill bit designed to "break up the rock and other material tending to wedge in around the upper part of the head" (lines 19-21). The drill collar forms "a connection between the main rotary drill shaft and the drill bit" (lines 13-15).
Date:
January 28, 1919
Creator:
Hughes, Howard R.
Item Type:
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Partner:
UNT Libraries Government Documents Department