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).
Technical drawing of a component with a left-hand single thread.
| Identifier | ExFiles\Box 170\2\ img100 | |
| Date | 8th December 1931 guessed | |
| L.H. SINGLE THREAD HELIX ANGLE . 7° 11' D.P. 6.61075 C.P. .69136 TOOTH FORM 0.15 P ADDEN. .177 DEDEN. .205 T AXIAL .30000 P.R AXIAL 30° P.R NORMAL 29° 25' NOTES AND STOCK G.M.C. X.1314-STEEL. HEAT TREATMENT. S.S.G N°4. STOCK SIZE -2 1/8"- .20633 .20573 1 7/8 +.01 -.03 3/16 R.{Sir Henry Royce} | ||