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).
Graph showing the results of a torsion test on a 20 HP crankshaft at various stages of machining, from forging to finished shaft.
| Identifier | ExFiles\Box 25\3\ Scan295 | |
| Date | 6th December 1927 | |
| FORGING DIMENSIONS: (AVERAGE) A.{Mr Adams} 2.375" JOURNAL E.{Mr Elliott - Chief Engineer} 1.200" OUTSIDE FLASH B. 1.900" CRANKPIN F.{Mr Friese} 2.550 WEB WIDTH. C. 1.100" WEB (THICK) G.{Mr Griffiths - Chief Accountant / Mr Gnapp} 4.625" CRANK D.{John DeLooze - Company Secretary} 1.350" FLASH. CRANK RADIUS 2.250" 20 H.P. CRANKSHAFT - TORSION TEST. FORGING TO FINISHED SHAFT. ① AS FORGED. ② JOURNALS TURNED FROM 2.375 DIA. TO 2.200 DIA. WEBS 1.015 THICK ③ CRANK PINS FROM 1.900 TO 1.625 DIA. WEBS .805 THICK. ④ JOURNALS REDUCED FROM 2.200 TO 2.030 DIA. ⑤ JOURNALS BORED 1.250 DIA ⑥ WEBS PROFILED FROM 2.550 WIDE (FORGED) TO 2.200 WIDE ⑦ CRANKPINS REDUCED FROM 1.625 TO 1.530 DIA. ⑧ CRANK PINS BORED .750 DIA. (FINISHED). TORQUE ON NOSE - LBS. FT. ANGULAR DEFLECTION - DEGREES. 9% REDUCTION IN STIFFNESS PER OP. 32.5% 35% 7% 10.5% 18% 6% 6% | ||