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).
Issues of friction and seizure in rear springs, particularly from Firth's manufacture, and proposing solutions.
| Identifier | ExFiles\Box 67a\2\ scan0183 | |
| Date | 22th September 1928 | |
| Hs.{Lord Ernest Hives - Chair} c to EY. c to Wor.{Arthur Wormald - General Works Manager} c to EP.{G. Eric Platford - Chief Quality Engineer} 48410 Hm{Capt. W. Hallam - Head Repairs}/NRC{N. R. Chandler}7/MW22.9.28. re SPRING FRICTION. We find that many rear springs, especially of Firth's manufacture, are badly and deeply seized at the ends of the plates; particularly is this noticeable on the plate which has the forged lugs on to carry the leaf clips, the reason for this being that this particular plate is much thicker towards its ends than are the other plates, consequently the proportion of load concentrated at the end is still greater. We find many rear springs in an extremely bad condition after quite a few thousand miles, and the riding very hard. We file the plates up so as to remove all the score marks, and incidentally remove the bedding farther back and greatly increase the bedding area before polishing the plates. We feel convinced, from observation, that this makes more difference in the comfort of riding than does a change of several 100 lbs in the poundage. Our experience indicates that the original Woodhead type of spring, with its rounded off and thinned off plates, is much less liable to seizure, and undoubtedly gives a much larger bedding surface as is clearly indicated on dismantling the springs for examination after some years of use. Another point is that the concavity of each plate is excessive, and results in bedding only for a very narrow strip along each edge of the pates. When filing springs to rebed them, we flat file them so as to make the bedding surface extend the full width of the plate for about 2" back, and then gradually dying off to the original several inches farther back again. We feel convinced that the very fact of increasing the bedding area, probably by several 100%, is likely to reduce the risk of seizure. We note that the springs as now received from Firths are a particularly bad job in this respect, some of the plates not touching on even 10% of the possible area, and until such time as we can get better bedding from the manufacturers, we are almost inclined to CONT'D.{John DeLooze - Company Secretary} | ||