| Year | 2005 |
| Date | 21-Jan |
| Volume | 194 |
| Issue | 4,239 |
| Page | 80 |
| Category | General |
| Part | 4 |
| Title | Paradoxical Gears (A new challenge; Intriguing Object) |
| Author | Jacques Maurel (France) |
| Notes | How to make a true involute gear. Definitions of the involute curve, making a 2-tooth step gear, other solutions for machining involute profiles, setting up, final question |