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).
Comparing material specifications for cast iron cylinder blocks between in-house production and an external supplier.
| Identifier | ExFiles\Box 132\4\ scan0078 | |
| Date | 25th June 1937 | |
| To Rm.{William Robotham - Chief Engineer} From RHC.{R. H. Coverley - Production Engineer} Handwritten: PHC/CM 124 RHC.{R. H. Coverley - Production Engineer}10/MJ.25.6.37. CAST IRON CYLINDER BLOCKS. It was my intention when chatting to you, to take up the question of Cast Iron Cylinder Blocks as Hs.{Lord Ernest Hives - Chair} had mentioned to me the Standardisation sheet which you had just issued and which showed a decrease of 10/8d. in Production Cost, but this is for the Midland Cylinder or Chromidium material specification. Since the cylinder was fitted to the Chassis which went to France certain progress has been made in our own foundry with a slight modification to material specification, and the deletion of Chills which was causing most of the trouble on casting production. From a machine standpoint these have turned out satisfactory and the prospects are bright with regard to considerable reduction in Scrap and since you are aware we are negotiating for another Foundry Manager and Metallurgical Assistant we would like to keep cylinder work in our own foundry rather than Sub-Contracting to the Midland Cylinder Company. Therefore, are you in agreement to the introduction of the material, the comparative specifications being - | | R.R. Production with use of Chills. | R.R. Production without chills. | Midland Cyl.Company or Chromidium | |---|---|---|---| | Total Carbon. | 3.5% | 3.2% | 3.43% | | Combined Carbon | 0.70% | .7% | 0.55% | | Titanium | 0.05% | .08% | 0.06% | | Manganese | 0.91% | .9% | 0.85% | | Silicon | 1.70% | 1.7% | 2.18% | | Sulphur | 0.10% | 0.09% | 0.10% | | Phosphorus | 0.29% | 0.25% | 0.11% | | Nickel | 1.00% | 0.95% | 0.08% | | Chromium | traces | - | 0.27% | | BRINELL | 244-271. | 248-260. | 205-214. | It will be noted that the variation in specification is very slight but the Brinell figures are up in comparison compared with Chromidium. After you have had an opportunity of considering the matter no doubt we can discuss the matter. RHC.{R. H. Coverley - Production Engineer} [Signature] | ||