| Year | 1937 |
| Date | 07-Oct |
| Volume | 77 |
| Issue | 1,900 |
| Page | 349 |
| Category | Tool-Room Topics |
| Part | |
| Title | Differential Indexing |
| Author | R.Hutcheson |
| Notes | The process of differential indexing, end view of the "Parkson" head, determining the change-wheels, some examples |