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).
The application and performance of Perfloc nuts with an accompanying photograph of them on a high-pressure pump.
| Identifier | ExFiles\Box 77\5\ scan0217 | |
| Date | 25th August 1914 guessed | |
| M.I.C.E., M.I.Mech.E. (page 8), whose opinion has since been amply confirmed by the behaviour of the nuts in practice. The other photograph, taken at the same time, shows one of several Perfloc nuts—marked by an arrow—used experimentally on a high pressure pump at Rickmansworth. The pump is subject to considerable vibration. It will be observed that the other nuts employed on the pump are double and that a split pin is used. The Perfloc nuts have been in position since December, 1911, and have required no attention whatever. Perfloc nuts are specially applicable to mining machinery. They may be left in inaccessible places with absolute security, and, being self-contained, no grit or dirt can affect the spring, which is also protected against moisture. The appended report of Messrs. Wm. Robertson and Sons offers conclusive evidence in this connection. A report by Mr. Rankine Lynn is also appended, showing that by this system such a good fit is automatically obtained as to make it impossible for the spring in the nut to be damaged by rust, even when the outside of the nut is heavily corroded by acid. It only remains to show that Perfloc nuts are at least as strong as ordinary nuts. Mr. Monkhouse is able to report (page 8) that at none of the loads were the nuts tested by him in any way injured, and that in each case the nut remained intact after the bolt had been broken; he also states that he does not consider that the Perfloc nut should be any more liable to damage through rusting action than is ordinarily the case. | ||