| All Patents in class 408/213 |
Patents 16 -
30
of 81
      |
| Number | Date | Patentee | Title | Type |
| RE3,516 | Jun. 22, 1869 | W.A. Clark | Improvement in expansive bits | adjustable drill bits |
| RE3,733 | Nov. 16, 1869 | W.A. Clark | Improvement in expansive bits | adjustable drill bits |
| 102,829 | May 10, 1870 | D. Kelly | Improvement in Boring Bits | drill bits |
| 104,404 | Jun. 21, 1870 | A.L. Andrews | Improvement in Auger Bits | auger bits |
| 104,457 | Jun. 21, 1870 | R.H. Hopkins | Improvement in Auger | auger bits |
| RE4,668 | Dec. 12, 1871 | W.A. Clark | Improvement in expansive bits | adjustable drill bits |
| 125,076 | Mar. 26, 1872 | H. Pitcher | Improvement in Augers | auger bits |
| 131,946 | Oct. 08, 1872 | E. Ford | Improvement in expansive bits | adjustable drill bits |
| 166,378 | Aug. 03, 1875 | S.W. Higgins | Improvement in Augers | auger bits |
| 199,391 | Jan. 22, 1878 | T.W. Wissinger | Improvement in Augers | drill bits |
| 202,061 | Apr. 02, 1878 | H.L. Shaler | Improvement in Augers | auger bits |
| 205,218 | Jun. 25, 1878 | G.F. Stearns | Improvement in Augers | auger bits |
| 254,184 | Feb. 28, 1882 | J. Morris, T. Wood | Auger-Bit | auger bits |
| 269,406 | Dec. 19, 1882 | P.A. Gladwin | Auger | adjustable drill bits |
| 270,200 | Jan. 09, 1883 | W.W. Brigg | Auger and gimlet | drill bits |
