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).
Complaint investigation regarding Bentley brake shoe bushes, resulting in a design change from bronze to nickel steel.
| Identifier | ExFiles\Box 102\6\ scan0213 | |
| Date | 17th August 1936 | |
| Hs{Lord Ernest Hives - Chair}/Pam. Hs{Lord Ernest Hives - Chair}/GWH.{George W. Hancock - Head Chateauroux} G.Sft.{Mr Swift} C.Moc. O.Hd.{Mr Hayward/Mr Huddy} C.H. BY/EWD. G.W.H. BY.11/G.21.8.36. COMPLAINTS GWH.{George W. Hancock - Head Chateauroux}5/JAB. 17.8.36. In regard to Mr. Hancock's complaint that the brake shoes on the front of the Bentley car examined in France appear to be short on the bush, and was so tight that the shoe would not work, whilst we did not doubt the phenomena described we were certainly inclined to doubt the cause of the trouble. Our own criticism being one which we had previously raised, but had been told did not occur viz. that the tightening up of the bush shortened the bush and increased its diameter, this time in view of the complaint I got Mr. D'Aeth to take an actual unit and tighten up the nut first, just merely nipping the bush, when the show was satisfactory, & then tightening up in a normal way, as one would secure a part permanently, and immediately the shoe was tight. The Works, however, were not tightening the nut down severely, but the fact that you could tighten up the nut so much that the bush was an integral part of the shoe, was sufficient evidence to indicate that the material was wrong. We have therefore instructed a nickel steel bush, which we similarly tested and the nut screwed hard up showed no tendency at all to cause the shoe to bind. I am therefore instructing Mr. D'Aeth and the Works to immediately introduce the nickel steel bush, cadmium plated, with an allowance on the dimension for 1/1000th on diameter of cadmium, and to scrap the bronze bushes immediately the steel bushes are available. We consider that this is undoubtedly a fault in design, and one which ought to have become evident earlier, particularly as we have raised the point we now demonstrate earlier on. We would recommend the Repair Department to replace the bronze bushes by the steel bushes in question on overhauls. Measuring a bronze bush before and after tightening up there is a reduction of .050 mmx in the length | ||