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).
Specifications for the AC 17 alloy used in bearings for Bentley or 20/25 cars, including composition and heat treatment.
| Identifier | ExFiles\Box 114\2\ scan0179 | |
| Date | 9th September 1935 | |
| To Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} X1020 Laboratory. HL.1/MN.9.9.35. The bearings for Bentley or 20/25 cars. Mains and big-ends are made from AC 17 alloy. Composition Tin 17.0 (± .5) Nickel 1.65 (± .1) . Antimony 1.0 Iron and silicon - about 0.3% Balance substantially aluminium. After "Casting-on" the duplex bearings are given a heat treatment, i.e. 1 hr. at 150 to 170°C. Brinell Hardness 24 to 30. Hl. HC | ||