Issued Patents All Time
Showing 1–2 of 2 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 5289889 | Roller cone core bit with spiral stabilizers | Marvin Gearhart, Johnny Castle | 1994-03-01 |
| 5145017 | Kerf-cutting apparatus for increased drilling rates | Jesse L. Holster, Roy D. Estes, Jack Castle | 1992-09-08 |