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).
Summary table of tests on tungsten contacts from various firms for high and low tension points.
| Identifier | ExFiles\Box 35\6\ scan 069 | |
| Date | 16th August 1921 | |
| X2894 16.8.21. X.2894 - TUNGSTEN FOR HIGH AND LOW TENSION POINTS X.3309. Ref. Letter | Firm. | Contacts or rods. | Description. | Remarks. ---|---|---|---|--- A | L.P.S. | C | L.T. contacts for Watford magnetos. | Fitted (First lot unsatisfactory by EHL/AT30.4.17. L.P.S. {Second lot lost. {Third lot awaiting test. Unsatisfactory 24.1.21. B | Gallenkamp. | R (.125" dia.) | L.T. contacts for R.R. battery ignition. | Expl. Shop unable to work into contacts. C | Delco. | C | Delco contacts obtained from Remy Elec. Co. | Fitted to screw and blade of R.R. battery ignition. Run on 10,000 mile car (2EX) (Unsatisfactory possibly owing to imperfect condenser connection D | B.T.H. | R (.125" dia.) | L.T. contacts for R.R. battery ignition. | Expl. Shop unable to work into contacts. E | Ind: Lamp & Wire Co. | C | for Bosch magneto. | Awaiting fitting and test. Unsatisfactory 24.1.21. F | Ind: Lamp & Wire Co. | C | Delco | Not suitable for use. G | Ind: Lamp & Wire Co. | C (.070" diam.) | -- -- -- | Diameter too small for use. (form details in left margin) R R.{Sir Henry Royce} 382A 100/T/S H.{Arthur M. Hanbury - Head Complaints} 159. 11-5-20 G.{Mr Griffiths - Chief Accountant / Mr Gnapp} 2800 | ||