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).
Issues and potential solutions for brake drums on the 40/50 HP chassis, including distortion and heat treatment problems.
| Identifier | ExFiles\Box 120\1\ scan0036 | |
| Date | 16th January 1931 | |
| [STAMP: RECEIVED 16 JAN 1931] x4612 BY1/G.16.1.31. Hm.{Capt. W. Hallam - Head Repairs} Hd.{Mr Hayward/Mr Huddy} Hs.{Lord Ernest Hives - Chair} C.S. C.W.H. RE 40/50 HP. CHASSIS - RE BRAKE DRUMS SUITABLE FOR SIDE BY SIDE SHOES. ------------------------------------------------------- Referring to Hm{Capt. W. Hallam - Head Repairs}5/VA/GM.12.1.31. and Hd{Mr Hayward/Mr Huddy}/SB{Mr Bull/Mr Bannister}16/KH. 12.1.31. which deals with similar points, the greatest amount that it is permissible to take out the above type of brake drum is .062" on diameter. There is not much value in our heat treating the drums, as the brinell drops immediately they have a long run and the drums get heated up. Secondly, the drums distort in the heat treatment and stretching would not ensure the drum remaining truly circular permanently. The whole question is receiving very careful attention. New brake drums are being considered for both front and rear, in which ribs are added to the outside of the drums, so as to bring the drum back into line with the old rear Phantom 1 type. I am going into the question of whether we can recommend production of liners which have been hardened and ground to accurate diameters and then forced into the turned out brake drums to produce a new wearing surface. This, I think, may be possible as a means of repairing the old type drums which are in service rather than to go to the extreme expense of replacing the drums with the new type under consideration with cooling ribs. There are certain chassis which in my opinion will have to have the drums changed viz. where cars are running regularly in mountaineous countries and I think the case that Hm.{Capt. W. Hallam - Head Repairs} mentions is an instance that will have to be dealt with on this basis as soon as we have settled the question of testing out the new type. BY.{R.W. Bailey - Chief Engineer} | ||