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).
Costs of Phantom III tappets and potential alternatives for cost reduction.
| Identifier | ExFiles\Box 148\5\ scan0159 | |
| Date | 27th April 1937 | |
| C/Mr. Copy to RHC.{R. H. Coverley - Production Engineer} Rm.{William Robotham - Chief Engineer} HRC. Ray/Smith. 1260 E/PSN.3/M.27.4.37. P.III - TAPPET COSTS. The cost of the P.III. tappets as shown on the cost sheets with overhead charge of 200% is 4.2/- each, but to this figure should be added the cost of chromium plating which is 1/2d each, making a total cost for 24 tappets £6.9.0. per engine. Now that the tappets are working satisfactorily, we wish to continue development with the object of reducing their cost. Before commencing development, however, we wish to know the saving we are likely to obtain from the following possible alternatives:- (1) Cast iron tappets to E.86925, but made by R.R. instead of Pattison & Hobourn, and chilled on the cam contact face and chromium plated. We should anticipate a considerable saving in machining. (2) Nitrided tappets to E.87336 in Hykro and no chromium plating. The only operation after nitriding should be polishing. (3) 3½% nickel steel tappets to E.87336 chromium plated all over to provide a good bearing surface on all contact surfaces. (4) 3½% nickel steel hardened to 302-321 brinell machined in the heat treated condition, and chromium plated on the cam contact face only. We should also appreciate Works comments on these alternatives from the point of view of ease of manufacture. E/PSN. | ||