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).
List of specifications and agreed procedures for body mounting, including subframe dimensions, rear axle alignment, and bonnet contouring.
| Identifier | ExFiles\Box 14\8\ Scan281 | |
| Date | 11th October 1930 guessed | |
| (2) (7) We must put on the chassis print a definite dimension from the under side of the subframe to the under side of the body tack rail, thus - [Diagram with labels .500 and +-.150] which will give a normal clearance of .500 but due to limits at the upsweep and the front bracket may vary between .500 plus or minus .150". (8) The rear axle will be held to the centreline of the chassis frame with limits of plus or minus .125". This must not only apply to the chassis as tested in Derby under correct load, but must equally apply when springs have been changed after the body has been fitted. We understand that it is hoped that this will be achieved by greater accuracy in the spring leaves, and not be selective assembly, which the changing of rear springs rules out. The present transverse adjustments at all the supports will be adequate. (9) The maximum variation of the scuttle isolation gap, assuming the body scuttle face to be dead accurate will be .100". The scuttle isolation drawing should state that the body should be so mounted that the rubber washer in the narrowest part of the gap be compressed to .350" and that packing washers of sheet aluminium be inserted behind the other rubber washers to give this degree of compression. (10) On N.2. series the bonnet passes over the dash, and it is the configuration and height of the hinges of this relative to the front subframe brackets that is vitally important. The bonnet angle should be riveted in a jig located from the shoulder of the dash. The top eye should also be similarly located. (11) It was agreed that the following Works procedure be advisable:- (a) The subframe be erected in a jig and if possible partially riveted in that jig. (b) That chassis be drilled for subframe brackets with the brackets held in position in a jig representing the entire subframe. (c) That a jig representing a subframe be supplied to Test Dept. Derby, to test each chassis under load before despatch. (d) That coachbuilders be encouraged to build a jig representing a chassis to test bodies on. It is not feasible for us to supply gratis or sell such a jig - the cost to us or the coachbuilder being prohibitive. (e) That we be able to guarantee the contour of our bonnet at the dash to be within .050 of the accurate in any one point. When we can do this bodies can be completed, painted, and trimmed prior to mounting of great value to us in England and on the continent, and essential to RRAI: DA{Bernard Day - Chassis Design}/EV.{Ivan Evernden - coachwork} | ||