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).
Design and materials for semi-floating rear axles, comparing American and British practices.
| Identifier | ExFiles\Box 114\1\ scan0129 | |
| Date | 4th May 1938 | |
| To By.{R.W. Bailey - Chief Engineer} from Rm{William Robotham - Chief Engineer}/Gry.{Shadwell Grylls} c. HS.{Lord Ernest Hives - Chair} c. Da.{Bernard Day - Chassis Design} c. Edy. Rm{William Robotham - Chief Engineer}/Gry.{Shadwell Grylls}3/WH.4.5.38. 1015. SEMI-FLOATING REAR AXLES. Mr.Daniell visited us yesterday and gave us the latest information from America with particular reference to the Salisbury or American Spicer axle. This axle is now being used by Buick Graham and Studebaker. The hub is fixed on a taper. The figures they now work to using SAE.4140 steel for the half shaft are :- Stress due to bending only 15000 Stress due to torsion only (1st. gear) 55000 They recommend SAE.4140 steel which is a steel very much cheaper than what we use. There should be a machined parallel portion 3" long 1/16 smaller in dia. than the root of the splines, next to the splined end. The taper from this plain portion to the large end is left black. In England rolled half shaft forgings can be obtained from the Scottish Steel Stamping Co., and the material from The Premier Steel Co. Taper construction is preferred to an upset end because of the better shaft forgings that can be obtained. To prevent shaft failure and bearing failure the angular deflection of the axle tube must be the same as the shaft. For Bentley II the Spicer Co. would recommend a shaft 1 3/8 under the bearing and 1.3/16 for the parallel portion next to the splines. The tube should be 2 3/4 dia. x 1/8 section or its equivalent in deflection. The Americans are using .15 Carbon steel tubes. The tube stress in normal bending is 11-12000. Rm{William Robotham - Chief Engineer}/Gry.{Shadwell Grylls} | ||