| All Patents in class 408/190 |
Patents 1 -
10
of 10
      |
| Picture | Number | Date | Patentee | Title |
 | 63,882 | Apr. 16, 1867 | A.P. Gruger | Improved Device for Cutting Washers |
 | 115,587 | Jun. 06, 1871 | R.H. Dorn | Improvement in circular cutters |
| | 143,738 | Oct. 14, 1873 | H.E. Whipple | Washer-Cutters |
 | 195,877 | Oct. 09, 1877 | D.F. Barber | Improvement in Countersinks |
 | 256,979 | Apr. 25, 1882 | J.W. Cooper | Washer Cutter and Adjustable Bit |
 | 326,342 | Sep. 15, 1885 | J.C. Smith | Adjustable Concentric Channeler |
 | 458,091 | Aug. 18, 1891 | C. Beauchene | Expansion-Bit |
 | 596,420 | Dec. 28, 1897 | F.W. Britton | Expansion Router-Bit |
 | 3,241,404 | Mar. 22, 1966 | F. Sirola | Boring tool |
| | 4,231,691 | Nov. 04, 1980 | H. Woerz, D. Pape | Dual Cutter Boring Head |
