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).
Gear, bearing, and material considerations for engine and transmission components.
| Identifier | ExFiles\Box 173\4\ img108 | |
| Date | 1st December 1935 | |
| -2- enough to finish hob or broach. He suggests also use of a cast iron cap. (2) The gears should have the splines finished first and the gear teeth operation done with the gear mounted on a splined arbor for concentricity. Selective assembly would ensure good fitting. (3) End load the shafts. (4) The sliding piece should also have involute splines as long as possible for oil cushioning. (5) Taper Timkens on the lat. motion shaft would be quieter and shorter than the present arrangement. As regards erratic synchromesh operation Thompson condemns lapping of the cones and the use of EP{G. Eric Platford - Chief Quality Engineer} oils. He suggests the final steel cone should be diamond bored with a coarse prim feed to leave tool marks clearly visible. The 100 per inch thread on the bronze also helps. The use of lapping paste gives inconsistent results. Cadillacs use a male of 20' larger to allow for distortion of the female cone. Taper Timkens instead of plain bushes for the free pinions helps to line up the synchromesh cones. Next we met the bearing experts who one and all condemned cadmium. It has a life about 3 times whitemetal provided no acid forms in the oil. With the present high grade oils and Ethyl Fluid the bearings corrode away very quickly at high temperatures above 100°C. In some cases in 400 miles. The acid content of the oil is preventable by having sulphur in the oil which the refining processes remove. Cadmium will run successfully on cheap low grade oils or on oil to which sulphur has been added. The latter is not on the market. The sulphur will produce sludge but although not looking nice does no harm except to silent tappets. G.M. have been experimenting with copper lead and have come to the following conclusions - (1) The present lead bronze as H.R. make it requires large clearances to accommodate crankshaft and crankcase distortion and will run satisfactorily at small clearances if (a) bell mouthed the right amount initially (b) the engine is stiff enough not to deflect - the only engine stiff enough being the large Packard. (2) Copper lead 55 : 45 instead of 20 : 30 will run in any engine at whitemetal clearances if made by this new process of rapid drenching in shallow flat trays. After | ||