| Year | 1972 |
| Date | 20-Oct |
| Volume | 138 |
| Issue | 3,451 |
| Page | 1,034 |
| Category | Correction |
| Part | |
| Title | Co-ordinate Marking Out |
| Author | "Tubal Cain" |
| Notes | Location of holes from edges, location from given centre-lines, setting to an existing hole, more complicated hole arrangements, holes in a circle, holes dimensioned to radius & pitch, holes in triangle-angles not known, useful special case & accessories |