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).
Bearing production methods and supplier visits to Allison and Bohn Aluminum in Detroit.
| Identifier | ExFiles\Box 173\1\ img331 | |
| Date | 26th January 1934 | |
| SG{Arthur F. Sidgreaves - MD} NOR RGE BY LR{Mr Ellor} / HE / RHC{R. H. Coverley - Production Engineer}/KW 15-2.34 Statler Hotel, Detroit, Michigan, U.S.A. To H.{Arthur M. Hanbury - Head Complaints} S. From R.{Sir Henry Royce} H.{Arthur M. Hanbury - Head Complaints} C. January 26th, 1934. Owing to delay in producing Bearings, and fact that test tackle was ready, it was useless to remain at Indianapolis, therefore decided to move to Detroit for purpose of visiting other concerns as cabled. Allisons for purpose of test, are producing bearings in 60/40 and 70/30 which will be made with standard oil grooves to Drawings. They are anxious to produce plain bearings, it has been laid down however that for tests, bearings must conform to drawings submitted; it was ascertained that method of producing is to machine surfaces, rough in form of shallow screw thread, copper plate and cast by pouring into stationary moulds produced in steel, which after casting are quenched rapidly, centrifuging is not used because they have failed to carry it out satisfactorily; it has therefore been abandoned for that reason. The reason Allisons do not like Marine Type Bearings, is owing to difficulty of producing same; any form of internally lined, or bearings which are externally or internally lined (similar to Bristol big ends) providing they are plain, can readily be produced by static process. It has been our practice to step flange on bearing joint face. Allisons consider this should be left plain. This gives better support and prevents bearing closing in; this has been overcome at works with stress releasing treatment which bearings of all types are given, there is no reason however why step should not be deleted, it was of course adopted, because it was practice on White Metal Bearings. PROPOSED BEARING PRESENT BEARING I visited Bohn Aluminum, Detroit, Wednesday, January 25th, who also produce lead bronze bearings, and are in competition with Allisons. It was interesting to find that they produce bearing by normal casting process, and had given up centrifuging because they could not succeed. Bohn use straight lead bronze which varies between 70/30 and 60/40 composition; Bohns also confirm information obtained regarding plain bearings and have proved that best form of bearing is similar to that already reported with external groove and 6 - 8 -1/8 Dia. holes for lubrication; with the number of holes there is less risk of breakdown in lubrication, incidentally they were much impressed by R.R. big end bearing which was considered to be an excellent job, the scrap on their pro-duction being 30%, lead bronze produced in strip form and then folded is also made by Bohns. .RAD .125 Dia .187 Dia | ||