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).
Complaints of bending push rods on the Bentley chassis, proposing material changes and temporary hardening solutions.
| Identifier | ExFiles\Box 88\4\ scan0183 | |
| Date | 17th November 1936 | |
| BY/CS. c. Rm.{William Robotham - Chief Engineer} e.{Mr Elliott - Chief Engineer} Rm{William Robotham - Chief Engineer}/SWH. Handwritten: Pedes 254 BY.6/G.17.11.36. BENTLEY CHASSIS - PUSH RODS. We are having complaints that the push rods on the Bentley chassis are bending slightly under the load. I think that you will find that the rods in question are made from S.Z.N. and I wish to have this material modified to S.Z.N.X. The difference in tensile between the two types of material is that we shall have approximately a 45 ton minimum on S.Z.N. whereas the minimum on S.Z.N.X. will be 60 tons. This difference will be sufficient to prevent recurrence of the trouble. If we have a number of the parts already formed I would suggest that the parts in question are hardened from a cyanide bath, no protection being given to the length of the rod between the two ends. This would give a sufficient depth of increased carbon to prevent the bending in question taking place. This latter, of course, is a temporary expedient to deal with rods which may be produced but not fitted. The same will apply to the 25/30. Handwritten notes: Swell. ① Do the 25/30 ever bend. I see no reason why they should. BY.{R.W. Bailey - Chief Engineer} Same Price ② What will be the difference in cost of the suggestion i.e. S.Z.N.X. ③ Would it not be cheaper to make the rods slightly thicker. Is there any reason why we should not do this. Rm.{William Robotham - Chief Engineer} | ||