| Patents for Charles H. Irwin |
Patents 1 -
7
of 7
      |
| Number | Date | Patentee | Title | Type |
| 306,907 | Oct. 21, 1884 | W.M. Dimitt | Auger Bit | drill bits |
| 361,522 | Apr. 19, 1887 | C.H. Irwin | Auger Bit | drill bits |
| 378,251 | Feb. 21, 1888 | C.H. Irwin | Die for Making Auger-Bits | making drills and augers |
| 404,197 | May 28, 1889 | C.H. Irwin | Auger-Bit | auger bits |
| 427,325 | May 06, 1890 | J.E. Hitch, F. Mill, C.H. Irwin | Boring-machine | portable timber mortisers |
| 430,344 | Jun. 17, 1890 | F.I. Hoefle | Single Twist Auger Bit | auger bits |
| 1,128,986 | Feb. 16, 1915 | C.H. Irwin | Angle Plate | track angle plates |
