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).
Summary of findings on plain bearings and surface finishing techniques.
| Identifier | ExFiles\Box 178\2\ img084 | |
| Date | 7th February 1940 | |
| Rm.{William Robotham - Chief Engineer} Plain Bearing and Surface Finish -3- articles of faith.And G.M. are contributing more to the subject (such as oil tests,new bearing metals,thin white metals,etc.) than Chrysler is doing. (4) On Jan. 31 Lessels and I both attended a session in research of which notes are attached. (5) Feb.1 Lessels and I visited Connor at Micromatic Hone and then had further talks with G.M. research.Notes on these two visits are attached. (6) Altogether we have been going around a lot and think we have learnt plenty. On the particular subject of plain bearings we can try to summarize everything as follows: (a) There is such a thing as a "fuzz" layer on all work which is machined to size in such a way as to generate heat.Exact composition unknown. (b) This can be removed by the various methods of honing probably better than in any other way,since,as distinct from lapping, the hone uses bonded abrasive and therefore brings the cutting edge firmly in contact with the work. ("Sandpaper" cutting,often described as lapping,is really a form of honing.) (c) There is no practical need to divorce the sizing operations in separate machines.The one machine is perfectly capable of doing both jobs.(as in honing cylinder bores).The sizing and surfacing have to be done in successive operations. (d) In the presence of E.P. lubricants under heavy loads mirror surfaces may be undesirable thru not "striking" the sulphur out of oil before seizure occurs. This is a particular case but according to G.M. it applies to bearings used with E.P.lubricant in rear axles,in which too smooth a finish is undesirable. (e) In the particular case of C.I. rings in C.I. cylinder bores the argument for high finish is by no means certain.There is evidence that "co-directional" honing,giving as closely as possible the texture of a run-in bore is the most desirable finish.A missing link in this subject is the lack of knowledge of the true shape of the bore under a load. | ||