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).
The failure of a steering pivot during a bumping test, with suggestions for improvements.
| Identifier | ExFiles\Box 2\B002_X168\ 00000001-page234 | |
| Date | 2nd February 1914 | |
| From Exp. Dept. Copies for: J.{Mr Johnson W.M.} H.{Arthur M. Hanbury - Head Complaints} Da.{Bernard Day - Chassis Design} Ha. Wor{Arthur Wormald - General Works Manager}/HyS/LS214. February 2nd. 1914. Report on Steering Pivot P.3783. X.168 One of these pivots which has been in use on the bumping test has broken off at the stub axle at the point where the recess turned on the taper part commences. It ran for 23 hours 55 mins. before breakage at 105 bumps per minute. The radius is rather small and it is advisable that this be made larger or that it should be tapered off from one diameter to the other. It might be advisable to thicken up the metal a little by not recessing so deeply. [Diagram of a steering pivot with an arrow pointing to the break point, labelled 'Broke here'] I think the boring out of the stub axle should be better finished. On the pivots which I have had the metal appears to be torn out rather than cleanly cut and this causes annular grooves to be formed, some of these are deep enough to weaken the piece. Since writing the above I hear from Mr Day that the radius of the recess has been materially increased. The particular pivot which broke had a very small radius indeed. | ||