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).
Moulding, casting, and design adjustments for M.40 Test Rig Tappets to address cracking issues.
| Identifier | ExFiles\Box 109\5\ scan0207 | |
| Date | 21th July 1941 | |
| Rm{William Robotham - Chief Engineer}/HH. (Belper) X c to Rm.{William Robotham - Chief Engineer} (Belper) c to Jnr.{Charles L. Jenner} (Belper) 700 TB/KNG.1/JT.21.7.41. M.40 Test Rig Tappets. I thank you for your memo Rm{William Robotham - Chief Engineer}/HH.3/SW.19.7.41 and the history of previous tappets. Regarding tappets RE.1881-2 I attach sketch of method of moulding these and the position of the .125" circular drain hole. We should like a slight tapor inwards on this hole, as this would give us a little more thickness on the core-print. I am sorry I mislead you regarding the parallel sides of the slots as they would have to be on an angle for moulding purposes. A 30 deg. angle will allow them to mould, but if you wish you can have a 45 deg. angle. The small drain hole will be positioned on the joint line of the mould at the base between two slots, and opposite the third slot which will come on the joint line. Prints for two of the slots will be on the mould, the third slot print on the joint line on the core, and so will the print for the drain hole. Four tappets will be cast in one mould, the base end being open on an iron plate for chilling this end, the castings being run from the top on the .475" diameter boss. This will keep it grey for machining, the main body and face of the tappet being ground. I note you remarks of cracking occuring at the base face and travelling up to the drain hole in previous tappets, and propose to proceed with incorporating the drain hole on RE.1881-2 to see if the same trouble developes before passing further comments. TB/KNG. W. D.{John DeLooze - Company Secretary} Knagg | ||