| Year | 1956 |
| Date | 02-Feb |
| Volume | 114 |
| Issue | 2,854 |
| Page | 198 |
| Category | Expert's Workshop |
| Part | |
| Title | Machining large-diameter holes |
| Author | Duplex |
| Notes | Trepanning. The machining operation, greater accuracy of centring, cleaning-up operations, the Enox tool, other types of hole saws |