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).
Methods and challenges of creating reliable studded threads in aluminium.
| Identifier | WestWitteringFiles\P\2October1926-December1926\ Scan005 | |
| Date | 5th October 1926 | |
| TO HS.{Lord Ernest Hives - Chair} FROM R.{Sir Henry Royce} C. to BJ. WOR{Arthur Wormald - General Works Manager} (crossed out) RG.{Mr Rowledge} BY (crossed out) re. STUDDING IN ALUMINIUM. [STAMP: ORIGINAL] [STAMP: RECEIVED OCT 1926] [Handwritten: X3115] It is necessary to obtain a nice smooth reliable thread to make a success of studding aluminium. It is necessary to get the stud tightly put in over its whole length. It must be moderately tight for the whole of its journey. I think the stud should be threaded all the way, screwed a little below the surface, and the aluminium caulked over it. It is not economical to recess top of hole for a plain portion left on the stud: also stud may only be tight at the top. This caulking will have the advantage of removing the burred raised portion round the stud, but we cannot believe that this small amount of aluminium pushed over the stud can have any effect in holding it, if it is not otherwise tight. It will also be noted that if the stud is not a very good fit in the thread the locking burr will have to carry the load, after which we should imagine the stud would be slack. Naturally the studs must be standard size for all metal, and probably special taps for aluminium. Taps for aluminium should not be backed off much - i.e. plenty of guiding control, and not liable to roll in cutting when backing. We arrange to tap through where-ever possible. It may be necessary to machine tap under-size, and re-tap by hand slightly larger, but still slightly undersize: daywork as an inspection process. For a long time we avoided tapped aluminium, but find the Americans saved much weight, cost, and difficulty, by doing so, hence we must make a success of the same. R.{Sir Henry Royce} | ||