From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Blueprint showing a cross-section of a threaded mechanical component with dimensions.
| Identifier | ExFiles\Box 171\3\ img166 | |
| Date | 18th May 1925 guessed | |
| TAP 1.500 DIA 16 THDS PER 1" R.H. .900 DIA .150 RAD .50 .500 DR | ||