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).
Measurements of the parallelism and 'skew' errors of timing gear axes on a Bentley Unit (B-4).
| Identifier | ExFiles\Box 136\1\ scan0154 | |
| Date | 18th May 1935 | |
| To Hs{Lord Ernest Hives - Chair}/Rm{William Robotham - Chief Engineer}: X115 Hs{Lord Ernest Hives - Chair}/FJH.{Fred J. Hardy - Chief Dev. Engineer}1/KW.18.5.35. Accuracy of Timing Gear Axes. We have made some measurements of the parallelism of the timing gear axes on a Bentley Unit (B-4). The errors measured were the "skew" errors, i.e., at right angles to the plane containing the two axes. The variation of centre distance was not measured because it is relatively unimportant so far as the gears are concerned, and is more difficult to measure accurately. The results are shown below where the "skewness" of the shafts is expressed in thousandths per inch. As the timing gears are 1.000" wide this represents the amount of separation of the teeth on one side of the face. Between Crankshaft & Camshaft 0.2 thou. per inch. " Camshaft & Dynamo 1.1 " " " " Camshaft & Idler Gear 0.4 " " " " Idler Gear & Water Pump 0.5 " " " As we consider that 0.25 thou. per inch should be the maximum allowable error, the above results are very bad. The above error of 1.1 thou. per inch was demonstrated to the Production people, who agreed to carry out similar measurements on a number of production engines with a view to obtaining some representative figures. Hs{Lord Ernest Hives - Chair}/F.J.Hardy. F.J.Hardy | ||