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).
Test report comparing standard tapers and splines under static and vibration loads.
| Identifier | ExFiles\Box 111\4\ scan0080 | |
| Date | 28th October 1938 | |
| -2- HPS{Horace Percy Smith - Experimental Factory Mgr}/WB.{Mr Brazier/Mr Bell}5/CB.28.10.38. Static Test. Rolls-Royce Standard Taper - without Key. The initial torque required to make the surfaces slip was measured four times, the average figure obtained being 450 lb. ft. It is, of course, essential for surfaces of this kind to be well matched initially, if they are required to transmit a high torque without slipping. Barber-Colman Taper Splines. In this case, the average torque found necessary to make the surfaces slip was 310 lb. ft. Vibration Test. As previously stated, the shaft fractured after 60 hours at 600 lb. ft., this putting an end to the existing test. Of the two couplings, the Barber-Colman was subjected to the more severe test, there being a certain amount of bending as well as torque applied to it - due to the rig being equipped with self aligning bearings. Rolls-Royce Standard Taper. No appreciable wear could be found on examination, but slight fretting has taken place at the small end of the taper, due to the washer; also a burr was formed at that end, as shown in BL.2218, Fig I. Otherwise, the coupling proved very satisfactory. Barber-Colman Taper Splines. Slight fretting took place on the tapered portion of the coupling and the washer caused fretting and burring at the end as with R.R. type. The fretting is shown on attached chart, BL.2218, Fig. II and that on the tapered portion may have been largely due to the bending mentioned above. There was an impression of the shaft serrations in the coupling piece - also illustrated in BL.2218, sheet II - produced during the vibration tests. This feature was barely evident in the test pieces after the initial tightening and was first observed during the first inspection after 100 hours at 225 lb. ft. continued. | ||