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).
Chart and diagrams detailing the recommended length and features of worm gear hobs.
| Identifier | ExFiles\Box 136\5\ scan0350 | |
| Date | 5th April 1940 guessed | |
| RECOMMENDED LENGTH OF WORM GEAR HOBS CHART (FIG. # 21): LEFT Y-AXIS: AXIAL CIR. PITCH OF HOB. RIGHT Y-AXIS: AXIAL DIA. PITCH OF HOB. X-AXIS: NUMBER OF TEETH IN GEAR. CHART NO 9 END VIEW OF HOB: SPACE OF GASHES CUTTING FACE (RADIAL SHOWN) KEYWAY HUB FACE OUTSIDE DIAMETER HOLE DIAMETER HUB DIAMETER STRAIGHT GASH SIDE VIEW OF HOB: LEAD TOOTH THICKNESS HOB PITCH DIAMETER BEARING (BOTH ENDS) THREAD LENGTH OF HOB ENLARGED VIEW OF HOB TOOTH (FIG. # 22): RADII ON TOPS OF TEETH STRAIGHT PORTION GEAR DEDENDUM S+F WHOLE DEPTH OF CUT D+F PITCH LINE PRESSURE ANGLE GEAR ADDENDUM START OF MODIFICATION HOB CLEARANCE | ||