| Year | 2021 |
| Date | 18-Jun |
| Volume | 227 |
| Issue | 4,667 |
| Page | 27 |
| Category | Workshop |
| Part | 3 |
| Title | Polygonal Holes & Rotary Broaching |
| Author | Jacques Maurel |
| Notes | Discusses the process of making non-circular holes. Assembling, uses for polygon holes when not for screw driving, nut sinking chart |