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).
Modifications to the speedometer drive gears to correct an undercut issue.
| Identifier | ExFiles\Box 165\2\ img173 | |
| Date | 20th April 1938 | |
| CHILDS .../NS.{Norman Scott} C. Rm.{William Robotham - Chief Engineer} 6065 DA.{Bernard Day - Chassis Design}9/G.20.4.38. B.111 and B.50. SPEEDOMETER DRIVE. We have discovered that the 8 Tooth gear driving the speedometer was undercut. In order to avoid this it has been necessary to introduce .050 of correction, compared with Wraith gears. As no reduction in the root diameter of the worm is possible, it has been necessary to modify all the gears, and the centres of the speedometer gears, as shewn on FD.{Frank Dodd - Bodies}160 herewith. The Wraith gears will be used as now made, but should it be desired, hobs ordered for the gears on FD.{Frank Dodd - Bodies}160 can in future be used also to cut Wraith gears. DA.{Bernard Day - Chassis Design} | ||