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 results for three different ignition contact points, highlighting issues with riveting tungsten points.
| Identifier | ExFiles\Box 35\6\ scan 389 | |
| Date | 23th December 1927 | |
| To R.{Sir Henry Royce} from EFC. c. BJ. E.{Mr Elliott - Chief Engineer} c. Ev.{Ivan Evernden - coachwork} Wor.{Arthur Wormald - General Works Manager} X2894 EFCA/T23.12.27. IGNITION CONTACT POINTS. X8692 Three further results are being sent for your inspection. One of these has run 10,000 miles on the bench with the old type of scrubbing action to Lec.2422, but with the arm thinned down for increased flexibility. The result apparently is not so good as with the original arm. With regard to the second sample, in this case the points were run with a combination of normal scrubbing action and quicker break cam, but unfortunately just towards the end the contact lever point worked loose and to some extent spoilt the result. In this connection we should mention that there is some difficulty with the riveting of tungsten points to the levers, and although this can be done more satisfactorily by the makers than by ourselves, nevertheless there is some percentage of trouble with those which are affixed by the makers. The riveting process is liable to chip and crack tungsten points and they have been known in a small percentage of cases to break off in bits or completely. For some reason this trouble seems to be much more in evidence now that we are getting these through on production lines - we had very little of this trouble wkhkx when the matter was wholly in the experimental stage. The third result sent you is an interesting one. It was suggested to me by Mr. C.A.Vandervell to try what he called "post office" metal for these contact points, which | ||