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).
Failure of force fit knurled assemblies and exploring alternative solutions.
| Identifier | ExFiles\Box 151\2\ scan0313 | |
| Date | 6th November 1936 | |
| LES. {Ivan A. Leslie} Believe you are dealing with this Rm. {William Robotham - Chief Engineer} 189#2 Rm. {William Robotham - Chief Engineer} c. Sft. {Mr Swift} RHC. {R. H. Coverley - Production Engineer} Da. {Bernard Day - Chassis Design} Hdy. {William Hardy} EV. {Ivan Evernden - coachwork} E.5/HP. 6.11.36. re Force Fit Knurled Assemblies. The figures obtained experimentally for the driving torque and slip torque on the above are about one tenth of what they should be for the purpose of their application. We are, therefore, forced to the conclusion that this scheme in which a soft knurled shaft is forced into a smooth hole is not a success. Alternatively we might use a serrated shaft forced into a serrated hole, or a hardened serration forced into a plain hole. The former is the one that suits our purpose better, and we have discussed the question of its production with the Tool department. The splining of the various shaft ends involved is the operation on which the limitations occur, and we understand the only alternative to cutting the serrations one at a time is to again use knurling. We are assured however that a knurled serration could be used in conjunction with a broached hole, and we, therefore, want to repeat the experiments with this combination. Da. {Bernard Day - Chassis Design} is issuing instructions accordingly for the dimensions required. E. {Mr Elliott - Chief Engineer} | ||