| Year | 1989 |
| Date | 04-Aug |
| Volume | 163 |
| Issue | 3,854 |
| Page | 138 |
| Category | Workshop |
| Part | 2 |
| Title | Hardness Tester |
| Author | Dave Lammas |
| Notes | Describes the function and building of an instrument for the home workshop. Optical measurement best, construction of the tester body |