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).
Graph plotting the results of a reversibility test on various worm gears.
| Identifier | ExFiles\Box 67\3\ scan0086 | |
| Date | 14th February 1925 guessed | |
| - REVERSABILITY TEST - LOAD ON PENDULUM LEVER (lbs) UNWINDING LOAD EAC SHORT WORM (X) EAC SHORT WORM ROLLER BRG (⊕) EAC LONG WORM (□) STANDARD 40/50 (⊙) | ||