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 comparing two different designs of broken Phantom III front suspension unit levers.
| Identifier | ExFiles\Box 95\3\ scan0193 | |
| Date | 19th December 1935 | |
| Micro-Examination Report. M1095. To H.{Arthur M. Hanbury - Head Complaints} (crossed out) By/De. (crossed out) Hs{Lord Ernest Hives - Chair}/Les.{Ivan A. Leslie} HL1/AC.19.12.35. Laboratory. Phantom III Front Suspension Unit Levers. As requested by Hs{Lord Ernest Hives - Chair}/Les.{Ivan A. Leslie} we have examined two broken levers of different designs :- G.81431. Broken on Bumper Test after 40 hours. 40 mins. using 3" cams. G.83836. Modified design. Broken after 30 hrs. using 3" Cams. The Brinell hardness of G.81431 was 264, whilst that of G.83836 was 288-293. Micro-sections, transverse to the direction of fracture, were prepared so that the polished surfaces intersected the starting points of the fractures. The micro-structures did not show any appreciable difference between the two levers. The macro-structure of G.83836 showed the forging lines to be more nearly at right angles to the fracture than those of G.81431. The fracture confirmed the results of the micro-examination. Since such differences exist, viz., the greater hardness and slight difference in macro-structure, favour the Lever G.83836, it would appear that the reason for this lever failing before the older type is not connected with the heat-treatment or structural condition of the levers. Hl. H.{Arthur M. Hanbury - Head Complaints} Levers returned to Hs{Lord Ernest Hives - Chair}/Les.{Ivan A. Leslie} | ||