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).
Table detailing the force required to move the cam lever on various magnetos.
| Identifier | ExFiles\Box 40\2\ Scan160 | |
| Date | 13th December 1926 | |
| X.8793 13.12.26. FORCE NECESSARY TO MOVE CAM LEVER ON VARIOUS MAGNETOS | Magneto. | Type | No. | Force (Lbs.Wt). | |------------|---------|-----------|-----------------| | B.T.H. | FM.6. | 356,071 | 1.0 | | B.T.H. | FM.6. | 356,147 | 1.5 | | Lucas. | EBA.6. | 156 | 1.0 | | Simms. | SRS.L. | 127,505 | 2.0 | | Simms. | SRS.L. | 127,536 | 2.6 | | Lucas. | ER.6. | 51 | 1.0 | | Scintilla. | GN.6. | 57927 | 3.5 | | Simms. | SRS.L. | 135,985. | 3.0 | | Simms. | SRS.L. | 135,986. | 2.6 | | Lucas. | ER.6. | 546 | 1.25 | EFC. [Handwritten text on right] BTH ✓ Lucas ✓ Simms ✓ Eque. C. | ||