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).
Fabroil Gear samples and their material properties for testing.
| Identifier | ExFiles\Box 136\1\ scan0049 | |
| Date | 17th June 1933 | |
| To E.{Mr Elliott - Chief Engineer} from ROY.{Sir Henry Royce} c. to Hs.{Lord Ernest Hives - Chair} ROY{Sir Henry Royce}1/MG17.6.33 Following our recent conversation re Fabroil Gears, the British Thomson Houston Company have now sent us samples (herewith) and write as follows: "Under separate cover we are sending you "three discs of Fabroil material cut from sheet, which "will enable you to make gears for trial on the lines of "those shown in the print we received from you this "morning. We are also sending you one Clement Talbot "moulded Blank, one Sunbeam gear, and one Renwick gear. "You may conduct any tests on the material and on "the method of fixing the metal centre that you may think "fit, and we invite you to also carry out any destructive "tests that may occur to you, as the blanks and gears are "of no value to us, being rejects on account of some minor "fault or other. "We are looking through our stock of moulds "to determine whether or not we have a mould sufficiently "near to your requirements to allow us to make for you one "or two moulded blanks for further test, as we appreciate "that the most satisfactory test is one carried out on a "specimen as nearly as possible resembling the size and shape "indicated on the drawing you showed the writer yesterday. "We will let you have our further remarks in this connection "within the course of a post. "In the meantime we give below a few figures "that are the average result of tests we have made from time "to time, in the hope that you will find them interesting:- Weight - .048-lb per cubic inch Transverse Strength - 21,500-lbs per sq. inch Resistance to heat - Up to 100°C. Tensile strength - 10,000-lbs sq.inch. Coefficient of expansion - .000035" per degree C. "To take care of the expansion of the material "it is usual to allow approx. .003" backlash between the "mating teeth to avoid crowding the teeth when the engine "heats up, but the actual amount of backlash can only be "determined by experiment, the desired condition being "freedom without backlash when the engine is at its normal "running temperature. (Continued) | ||