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).
Inspection charts for a gear hob, showing lead and modified tooth form.
| Identifier | ExFiles\Box 136\5\ scan0346 | |
| Date | 15th January 1940 guessed | |
| Left Chart: TYPICAL LEAD INSPECTION CHART OF GEAR HOB. Measurements: .0005, .0001. Vertical Axis: +4, +3, +2, +1, 0, -1, -2, -3, -4. Caption: Fig. #10. Right Chart: CONTOUR CHART SHOWING MODIFIED HOB TOOTH FORM. Vertical Axis: 0, .010, .020, .030, .040, .050, .060, .070, .080, .090, .100, .110, .120, .130, .140, .150, .160, .170, .180, .190, .200, .210, .220, .230, .240. Labels: HOB PITCH LINE, 20°, 14 1/2°, EFFECTIVE LIMIT OF MODIFICATION, AT PITCH POINT. Measurements: +.0002, +.0001, -.0001, -.0002, +.0005, +.0008, +.0010, +.0012, +.0015. Caption: Fig. #12. | ||