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).
Micro-examination report on a failed Ph.III mild steel servo brake lever, finding the cause to be pre-existing cracks from faulty forging.
| Identifier | ExFiles\Box 95\4\ scan0136 | |
| Date | 14th October 1936 | |
| +341/T Micro-Examination Report. M1202. To Hs{Lord Ernest Hives - Chair}/Mr. Martindale. HL4/AG.14.10.36. Laboratory. Re: Ph.III MILD STEEL SERVO BRAKE LEVER - E.83175F. In addition to the lever broken in service we have examined several others, and find that the failure is due to the presence of cracks near the centre boss. Micro-examination showed that these cracks were present in the stamping before the lever was fitted to the chassis. Part of one of the flaws found is shown in the attached photomicrograph No. A1,508, X150. From the shape and appearance of the flaws they are evidently due to faulty forging prior to stamping. We understand that the levers are made by the Midland Stamping Co. from their own material to our specification 201D. Hl. [signature] Photomicrograph No. A1,508 att. | ||