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 analysis of breaking steering pivots.
| Identifier | ExFiles\Box 2\B002_X168\ 00000001-page023 | |
| Date | 13th March 1913 | |
| From Exp. Dept. Copies for Mr Johnson Mr Royce Mr Spinney Mr Hulin 168 Report on Ex. 247 Steering Pivots Breaking. I have examined the pivots on all our experimental cars and been into the Repair Shop and examined the pivots on 12 cars there. I chose cars that had been run abroad, roughly. I examined 15 cars and I found 3 cracked pivots. Two of them were on one car (1795), this car has been run a lot in Newfoundland; the other one was on 1649 our old experimental car which has run a lot in France. All of the cracks are in the same place (except that one is a near side pivot), that is, in the front bottom corner, they are small and the paint had to be scraped off to show them up. Each of the pivots that are cracked are also bent torsionally. I have examined 5 pivots which have been taken off cars because the steering was stiff and I find all of them are bent torsionally, 1 of them forward and 4 of them backward. To prove exactly what causes a reversal of stress on the pivots and how much it is, I made the following experiment:- Got a standard cross steering rod, cut it in half, brazed a tube in one half which would slide in the other half, the two halves were held together by springs of a known strength, we then had a cross rod which was as stiff as the standard under compression but could move in tension. We had a collar on it which showed us the maximum movement and so gave us | ||