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).
Comparison of 'puddle-cast' and 'centrifugal cast' bearing production methods and an outline of the 'Strip type' bearing manufacturing process.
| Identifier | ExFiles\Box 114\2\ scan0125 | |
| Date | 13th March 1935 | |
| (2) RMC.1/MS13.3.35. outside suppliers. It is possible for either 'puddle-cast' or centrifugal cast bearings to be produced with 1 m/m - .039" steel backing and lead bronze lining of .015 - .020". Bearings produced by the Allison process have been run on Experimental Test Bed and Chassis engines and in one case failure of the material has resulted, which can be attributed to the radial structure obtained by this process which therefore suggests that it is not suitable for Conn. Rod duty. The centrifugal process gives a more reliable material structure for Conn. Rod duty because the laminated or 'onion-skin' structure will withstand the bearing loads with the excessive clearances required for this material, as proved by our Kestrel engine experience. There is the additional advantage that in the case of Chassis engines bearings are to be used on hardened crankshafts and are not so liable to material fracture as either Allison or Strip type processes which is confirmed by recent correspondence from America as it will be observed that they are compelled to resort to Cadmium Nickel Alloys, not on the grounds of cost but on the grounds of reliability. The production of Strip type bearings makes it impossible to carry Lead Bronze over the flanges owing to the risk of fracturing the material and affecting adhesion due to the folding. Therefore, the 'puddle-cast' and centrifugal cast processes permits of the Lead Bronze being extended round the flanges. The process employed in the production of Strip type bearings is outlined as follows:- Op. 1. Material is prepared and cast in the form of a tray which is large enough to make from 6-12 bearings. Op. 2. Then cut into the required length for individual bearings. Op. 3. Surface broach down to the required thickness. continued. | ||