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).
Specifications for disc production, including cushioning, run-out, and supply updates from Borg & Beck and Thermoid Co.
| Identifier | ExFiles\Box 129\1\ scan0188 | |
| Date | 17th June 1937 guessed | |
| -2- It is anticipated that it will be possible to recess the rivet head .040 for wear allowance subject to no undue difficulty being experienced in drilling the Thermoid to reasonably fine limits. The cushioning is nominally .060, but it is estimated that the actual cushioning will be between .040 and .050, the apparent discripency being partly due to penetration of the springs into the facing material, and partly due to the settling down of the springs after being first compressed. The question of run-out was also discussed, and it was agreed that it does not appear possible to work to .005 called for on the original drawing, the best disc of this type so far produced either at Derby or Leamington has a run-out of .007 the average being nearer .010. It was therefore agreed to produce discs with the smallest possible run-out, and if necessary to modify the allowance on the drawing after more production experience has been gained. Borg & Beck are proceeding with the production of 100 complete driven plates as quickly as possible (a) with drilled plates for first 100 or so, (b) for punched plates for larger quantities, on both cases the plate being ground on both sides, we providing the hub and rivets for securing the plate to the hub, Borg & Beck providing the brass rivets for the facings and the iron rivets for the cushion springs. The Thermoid Co. quote delivery of 2 weeks ex factory. Re Bentley. The position with 10" plates is as follows :- (a) We have already received two fitted with Thermoid, otherwise standard (one is being fitted to B-23-AE, standard axle shafts, damper removed). (b) 6 Long cushion plates with "Chevron" facings were shipped from America on June 3rd. also 12 Chevron facings and 12 Thermoid facings. (c) 25 more Long plates were ordered from U.S.A. June 9th, early delivery anticipated. Yours faithfully, FOR ROLLS-ROYCE LTD. | ||