Issued Patents 1989
Showing 1–2 of 2 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4869329 | Rock bit insert | Thomas W. Oldham | 1989-09-26 |
| 4836307 | Hard facing for milled tooth rock bits | Madapusi K. Keshavan, Lance D. Underwood, Thomas W. Oldham, Cary A. Roth, Brian J. Armstrong | 1989-06-06 |