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).
Manufacturing processes including final shaving, frame fixtures for aero engine cylinders, and the care of jigs, tools, and fixtures.
| Identifier | ExFiles\Box 96\2\ scan0083 | |
| Date | 27th November 1935 guessed | |
| 4. cont. The object of final shaving which is the equivalent of diamond boring, is not only to correct bores for size but also alignment in both planes, as a certain amount of crankcase distortion arises due to the releasing of internal stresses and handling during the machining operations. Since great pains are taken with timing gears to correctly produce tooth form by gear grinding, it is reasonable to suppose that timing gear troubles will be eliminated providing crankcase bores are machined to the required standard of accuracy. This process should also apply to gear boxes. Reaming has been in practice on production for some time but it is doubtful whether the required standard of accuracy can be obtained by this process because reamers will always prefer to follow existing bores which means the necessary accuracy is not obtained. 5. Frame fixtures for measuring aero Engine Cylinders. This was put forward as a means of checking the alignment of cylinder liners to prove accuracy of the top joint and is a more satisfactory method than the present system of clocking, because the constant disturbance of the clock indicator in transferring from one liner to another is sufficient to give rise to unsatisfactory readings and it was proved that the use of feelers made it possible to check to a higher degree of accuracy than could be obtained with clock indicators. The fixture also had the advantage of usefulness under any conditions, field service or test department, without the necessity for a surface table and clock indicator. In any event a fixture of this description will be absolutely necessary in the case of ramp type cylinders where there are so many studs which make it impossible to obtain reliable readings by the clocking process. Therefore a fixture suitable for one type of cylinder must be equally suitable for others. 6. Maintenance, Storage, and general care of special jigs, tools and fixtures. On completion of operations it is customary to remove fixtures from the machine and in many instances allow same to lie about the machine until they are again required, but when the necessity arises fixtures not only require cleaning before being put into operation but certain tool adjustments are necessary resulting in considerable delay before the operation can again proceed. This has the effect of increasing the cost of the manufacturing process. | ||