UNT Libraries Government Documents Department - 2 Matching Results
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- Drill-Bit
- Patent for new improvement in drill-bits. The object of the invention is to "provide the driller with advanced knowledge of the formation into which he is about to extend his main hole".
- Well-Drilling Device.
- Patent for well drilling device with new and useful improvements in well-drilling device for simultaneously drilling the main hole and an advance or "rat-tail" hole.