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).
Comparing blueprints and thread standards for spherical seated unions.
| Identifier | WestWitteringFiles\Q\January1927-March1927\ 15 | |
| Date | 5th January 1927 | |
| TO H.{Arthur M. Hanbury - Head Complaints} FROM E.{Mr Elliott - Chief Engineer} ORIGINAL E2/M5.1.27. C. to HS.{Lord Ernest Hives - Chair} SPHERICAL SEATED UNIONS. XZ170 We send you herewith blueprint of LeC. 2360. shewing the above made to reduced dimensions, and we also attach a print of LeC. 2183. for comparison, shewing the existing design. Thread diameters and hexagons it does not appear possible to alter, but practically all other dimensions, and wall thicknesses, have been reduced. The leading dimensions and the amount saved over LeC. 2183. are shewn in the table on LeC. 2360. With regard to the threads to be used, the following tables shew the threads we should naturally use (in the second column) to R.R. standard, and the threads we are supposed to use on aero work to the Air Ministry standard (in the 3rd. column.) THREAD DIA. | R.R. STANDARD NEW TYPE THREADS. | AIR MINISTRY STANDARD. ---|---|--- .375 | 24 | 20 .437 | 22 | 18 .5 | 20 | 16 .562 | 20 | 16 .625 | 20 | 14 .687 | 20 | 20 .750 | 20 | 20 .812 | 20 | 20 .875 | 20 | 20 .937 | 20 | 20 1.062 | 20 | 20 1.125 | 20 | 20 1.187 | 20 | This dia. not on list. 1.312 | 20 | 16. Side note: Air Ministry threads table II. According to our list there are no fine threads available in the Air Ministry standards below .687, and in the larger diameters there is one size that we require missing - e.g. 1.187. We should like to obtain the permission of the Air Ministry to use the second column. [STAMP] RECEIVED Hs{Lord Ernest Hives - Chair} JAN 6 1927 | ||