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).
And a diagram on the design and performance of a 12-cylinder gearbox, detailing gear teeth and synchro mesh.
| Identifier | ExFiles\Box 173\1\ img415 | |
| Date | 6th February 1934 guessed | |
| VI Gearbox. On the 12 cyl in particular remarkably good. They use 10 pitch teeth, 45° helix angle and use lapping only, no grinding. They modified the S.K.F. races slightly to take the increased thrust of the high helix angle, that is all. They have been using this box for two years with complete satisfaction. They got better results with 10 pitch than with finer gears due, they consider, to the fact that they found the finer teeth were deflecting as much as .003 under load. They fair off gears in a science room before fitting in box. They used a hot-lap much as we do on aerogear splines. They use a synchro mesh cone of 6°, width of face 7/8". dia at large end 3 3/4". To prevent slipping they t'worke very fine screw thread (100f 1") in the press f-piece of the cone, the only other treatment being radial slots for oil. [Diagram Labels] Screw Thread Slots | ||