| Year | 1921 |
| Date | 13-Jan |
| Volume | 44 |
| Issue | 1,029 |
| Page | 29 |
| Category | Workshop |
| Part | |
| Title | Some Modern Machine and Hand Tools |
| Author | George Gentry |
| Notes | Comparator for checking cylinder bores, the Birmel 3 1/2-in. screwcutting lathe, the Dalton Six type B-4 lathe |