| Year | 1939 |
| Date | 05-Oct |
| Volume | 81 |
| Issue | 2,004 |
| Page | 397 |
| Category | Model Machine Shop Practice |
| Part | 3 |
| Title | Hardening and Tempering |
| Author | Ernest F.Carter |
| Notes | Hardening, "case-hardening", "tempering", some hardeing hints, hardening and tempering tools, heat treatments of non-ferrous metals |