| Year | 1986 |
| Date | 07-Feb |
| Volume | 156 |
| Issue | 3,770 |
| Page | 160 |
| Category | Workshop |
| Part | |
| Title | Trepanning |
| Author | Tubal Cain |
| Notes | A repair completed and a workshop technique described. Repairing the pulley, tools for trepanning, machining the discs, trepanning in the drilling machine |