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).
Laboratory report on the hardness test of a Phantom contact breaker spring, noting careless tempering.
| Identifier | ExFiles\Box 142\3\ scan0331 | |
| Date | 4th September 1937 | |
| BY/RD. c. to Rm{William Robotham - Chief Engineer}/RC.{R. Childs} c. to BY.{R.W. Bailey - Chief Engineer} c. to Rm.{William Robotham - Chief Engineer} c. to Mw. 7204 M 1,404 H1/EJW.3/JN.4.9.37. Laboratory Re. PHANTOM CONTACT BREAKER SPRING - D.75146 Further to our report M 1,398. We have now received from Rm{William Robotham - Chief Engineer}/RC{R. Childs}, a D.75146 spring removed from 33-EX after 13,137 miles running, and which is described as having given no trouble. The hardness test on this spring gives 391 V.P.N. This is considerably softer than the previous satisfactory spring tested, which gave 540. So far our hardness test results have ranged from 391 to 653. It is evident that the tempering is being carelessly handled. Hl/E.J.W. | ||