| All Patents in class 408/212 |
Patents 1 -
15
of 56
      |
| Number | Date | Patentee | Title | Type |
| 13,261 | Jul. 17, 1855 | L.H. Gibbs | Expanding auger or bit | adjustable drill bits |
| 20,192 | May 11, 1858 | W.A. Clark | Method of seating the movable cutter in expansive bits | adjustable drill bits |
| 22,474 | Dec. 28, 1858 | H. Stone | Expanding bit | drill bits |
| 27,946 | Apr. 17, 1860 | J. Blake | Auger | adjustable drill bits |
| 29,793 | Aug. 28, 1860 | W.A. Ives | Single-Spur Double-Twist Auger Bit | auger bits |
| 29,883 | Sep. 04, 1860 | J.M. Hathaway | Adjustable Auger | adjustable drill bits |
| 47,946 | May 30, 1865 | C.L. Griswold | Improvement in Augers | auger bits |
| 52,056 | Jan. 16, 1866 | E.G. Lamson | Improvement in Augers | auger bits |
| 55,132 | May 29, 1866 | S.L. Lyford | Improvement in Gages for Augers | drill depth stops |
| RE3,879 | Mar. 15, 1870 | I.T. Payne | Improvement in Augers | auger bits |
| 111,099 | Jan. 17, 1871 | B. Walch | Adjustable Spur Auger | adjustable drill bits |
| 124,089 | Feb. 27, 1872 | H.S. Shepardson | Improvement in bits | drill bits |
| 131,946 | Oct. 08, 1872 | E. Ford | Improvement in expansive bits | adjustable drill bits |
| 141,324 | Jul. 29, 1873 | W.A. Clark | Improvement in Expansive Bits | adjustable drill bits |
| 155,333 | Sep. 22, 1874 | W.L. Parmelee | Improvement in expansion-bits | adjustable drill bits |
