| Year | 2021 |
| Date | 21-May |
| Volume | 226 |
| Issue | 4,665 |
| Page | 698 |
| Category | Workshop |
| Part | 1 |
| Title | Polygonal Holes & Rotary Broaching |
| Author | Jacques Maurel |
| Notes | Discusses the process of making non-circular holes. Striking, rotary broaching, measuring the concentricity of the machined bore |