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).
Report discussing the continual revision of drawings and the challenges of implementing modifications during production, using the Wraith gearbox as an example.
| Identifier | ExFiles\Box 6\6\ 06-page219 | |
| Date | 15th June 1937 | |
| - 2 - HPS.{Horace Percy Smith - Experimental Factory Mgr}5/VS.{J. Vickers}15.6.37. to design, there is a continual revision of drawings after issue. In fact, anyone can walk into the D.O. and get drawings altered without the consent or consideration of any responsible person. So far as is practicable, drawings issued to the Experimental Department are scrutinised before instruction to the Shops, but invariably with the introduction of a new feature there is a procession of people who want something altering to make parts easier to produce. In machining it often becomes apparent that times can be reduced by the introduction of modification to drawing, the Inspection Department draw attention to limits which call for alteration, and finally, on reaching the fitters, it is not unusual to discover that excessive hand-work is necessary in course of assembly, and so on. This happens with all new designs, but, unfortunately, the sequence of modifications does not end with the production of what is considered to be a satisfactory experimental car or engine unit, because it is not until after a successful 10,000 miles test that the Tool Office and Operation Planning Departments become really interested. We are then told that in certain instances perhaps the method of forging must be reconsidered and dies altered accordingly, or that drawings should be modified in order to reduce the number of machining operations, so that by the time these people have finished, we have what very nearly amounts to a new chassis. The Wraith gearbox is a very good example. The first detail drawings on this section were issued in August, 1936, and since this date practically every piece has been modified, in some cases as many as three or four times, during the production of experimental boxes. In all, the Design Office have sent us about 40 schemes since the first drawing was issued, and as a last resource, in order to try and straighten out the position, a set of parts was laid out for consideration by HHG. and other Production executives. This has resulted in a further crop of suggestions as to how the box generally should be modified to facilitate production, and this we regard as clear evidence that the Tool, Design and Operation Planning people should have had a say in the matter before any new designs were issued. continued. | ||