| Year | 1921 |
| Date | 28-Jul |
| Volume | 45 |
| Issue | 1,057 |
| Page | 72 |
| Category | Workshop |
| Part | |
| Title | Simple Types of Trammels |
| Author | |
| Notes | Trammel head, core box, pencil holder, washer plates, wide beam, light skeleton frame head, adjustable scribing points, open side head, small beam, spring adjustment, made from round stock, extension socket |