Number | Name | Date | Kind |
---|---|---|---|
2748298 | Calosi et al. | May 1956 | |
3089411 | Sollberger et al. | May 1963 | |
3328925 | Hewitt | Jul 1967 | |
3635609 | Balamuth | Jan 1972 |
Entry |
---|
Neppiras, "Special Ultrasonic Drilling Techniques", Metalworking Production, Oct. 5, 1956, pp. 1599-1604. |