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 manufacturing operation sequences for 'Delco' and 'HS/Rm' type pistons.
| Identifier | ExFiles\Box 28\1\ Scan278 | |
| Date | 15th October 1931 guessed | |
| These latter details, together with the elimination of the grinding process and a very plain initial casting make the production of the "Delco" pistons a cheaper proposition than the Hs{Lord Ernest Hives - Chair}/Rm{William Robotham - Chief Engineer} type, apart from the difference in the quantities produced. The following lists comparing the presumed "Delco" operation sequence with the actual O.P. list for the Hs{Lord Ernest Hives - Chair}/Rm{William Robotham - Chief Engineer} piston F.83727, show that the main difference in manufacture is operations 6 & 7. DELCO. 1. Turn & Face. 2. Mill all flat faces. (Possibly done in one operation.) 3. Drill all holes. 4. Counterbore. 5. Tap - Spring Screw Hole (One half piston only) HS{Lord Ernest Hives - Chair}/RM.{William Robotham - Chief Engineer} 1. Face, Turn & Centre. 2. Mill flat faces. 3. Bore, Cone & Turn step at back of large end & Face extreme point at small end. 4. Drill and C'Bore. 5. Burrs. 6. Fit in Pairs and mark. 7. Grind outside diameter. -------- | ||