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).
Recommendations for design and tolerance adjustments for damper, piston, and valve assembly components.
| Identifier | ExFiles\Box 99\3\ scan0048 | |
| Date | 19th January 1938 | |
| -4- HPS{Horace Percy Smith - Experimental Factory Mgr}/WB.{Mr Brazier/Mr Bell}1/EP.{G. Eric Platford - Chief Quality Engineer}19.1.38. However, since no trouble has been experienced on similar types of damper, there is no reason why the clearance between the connecting links FB.3409 and the rocking lever should not be more generous - say .020" The only trouble likely to be experienced from this source is that the jaws of the rocking lever may tend to close in when pressing in the pins, but that can easily be overcome by means of a pressing block. The connecting links have so far been produced from the solid, but would of course be forgings for quantitative production. The existing tolerances on the pins and pin bores in the rocking lever were found to be satisfactory. The reason for the groove on the underside of the rocking lever is obscure, therefore the operation appears to be unnecessary. Piston FB.3409. The pin bore in the piston should be the same as that in the rocking lever, i.e. .499" dia. +1/2 instead of .4985" +1/2 dia. as stated on the piston drawing. The internal machining operations in the piston to clear the connecting link should be deleted, the piston length being increased slightly if necessary to allow a more generous wasting tolerance, whilst the clearance between the sides of the connecting link and the pin bosses is sufficiently large to obviate the necessity for machining the inside faces - the tolerance between the bosses could be increased to .050" The chamfer on the piston skirt could also be included in the casting. The limits on the depth of the refill valve face, diameter, and width of retaining ring groove could be increased to at least .005" the only stipulation being that a note be added to the drawing that the valve face be a good finish. Refill Valve Assembly. If it is any advantage to production the .002" limit on the .0937" dia. central hole in FB.3414 Disc Valve could be increased to .005", since it receives only an aluminium rivet to secure the star spring FB.3412, the hole in which can be similarly modified. Produced to drawing FB.3413 Spring ring was found to be satisfactory. continued | ||