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).
Specification sheet detailing the carbon gap, copper gap, and button depression for a push-button switch.
| Identifier | ExFiles\Box 34\3\ Scan090 | |
| Date | 13th February 1925 | |
| X2641 13.2.25. X.9781ps. PUSH BUTTON SWITCH. X.8661. Position. Carbon gap. Copper gap. Button depression. Off. .040 ±15 .060±20 0 Carbons just in contact. 0 .033 ±10 .020±7 Coppers just in contact. 0 0 .045 ±15 (total) ------- ------- ------- COPY CHASSIS DEPARTMENT EFC. Issued 13-2-25 | ||