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).
The cracking of shock damper pistons and recommendations for heat treatment.
| Identifier | ExFiles\Box 151\2\ scan0364 | |
| Date | 4th August 1938 | |
| 1292. HPS. {Horace Percy Smith - Experimental Factory Mgr} c to Rm {William Robotham - Chief Engineer} /AFM. {Anthony F. Martindale} c to RHC. {R. H. Coverley - Production Engineer} RHC {R. H. Coverley - Production Engineer} /Vs. {J. Vickers} 4/JT.4.8.38. Iron Foundry. In reply to your memo HPS. {Horace Percy Smith - Experimental Factory Mgr} 2/VS. {J. Vickers} 20.7.38, we regret the delay in replying to same owing to being absent on holiday. We have now carefully investigated the position regarding the cracking of shock damper pistons EX.31344 with the following results. The cracking is no doubt due to the initial oil quenching operation, and since it is agreed that a brinell of 400 is desirable in this piece, and the only method of obtaining this brinell is by heat treatment, it is agreed that the best alternative is to thicken up the top recess which is now only approx. .028 thick to at least .10. This will entail a reduction of the diameter of the spring which fits in the recess. We would recommend that in the oil quenching of these pistons they should be placed in the tray with the thin ring to the top so that the rate of cooling of the thicker portion of the casting is assisted to partially equalise with that of the thin section, RHC {R. H. Coverley - Production Engineer} /Vs {J. Vickers} [Signature] | ||