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).
Drawing of an exhaust valve seat.
| Identifier | ExFiles\Box 140\3\ scan0227 | |
| Date | 14th November 1938 | |
| R.R. 885(2 1/2 H/43003-10.6.37) N & G LTD No OPERATION MACHINE TOOL TOOL No. SEE ON LIST VALVE SEAT TO BE MACHINED WHEN IN POSITION IN CYL. HEAD. THREAD & SEATING MUST BE CONCENTRIC. CYLINDER HEAD TO BE HEATED TO 300F BEFORE SCREWING SEATING IN POSITION. ALL DIMENSIONS ARE EXPRESSED IN INCHES, ALL LIMITS IN THOUSANDTHS OF AN INCH. SCALE 1/1 MACHINE ALL OVER OR WHERE MARKED THUS HEAT TREAT BRINELL TITLE VALVE SEAT - EXHAUST MATERIAL FIRTHS N.M.C. SPECN No REPLACE ALL COPIES TO:-- EXP. / PATT WORKS / FORGE T.O. / S.R. D.O. / R.D. T.D. / COST DRAWN TRACED YAH CHECKED APPROVED LIMITS O.K. DATE 10-12-37 USED ON PH III No. OFF 12 SECTION 5050 E.89239 TURN 1.500 - 1/2 DIA SCREW 1.500 +- 20 T.P.I." R.H FULL THREAD TO GAUGE SIMILAR TO E.88171 BUT HAVING A FULL FORM THREAD. 8 SPLINES EQUALLY SPACED. CHAMFER .025+10 AT 45° +2° -0° ROLLS-ROYCE LTD. PRINT ROOM 14 NOV 1938 DERBY E.89239 DIMENSIONS: 1.350 DIA. +10 -0 25° +1° -0° 1.200 DIA. +5 -0 1.080 DIA. +5 -0 .250 +5 -0 .025 RAD. +10 -0 .350 +5 -0 20° +1/2° -1/2° 1.434 DIA. UNDERCUT -5 1.650 DIA. -5 .300 -5 .525 -5 | ||