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).
Graph showing curves for helix angles, pitch, and gear ratio for Marles-Weller gears.
| Identifier | ExFiles\Box 28\2\ Scan064 | |
| Date | 1st March 1932 | |
| B.F.3.32 GEAR RATIO 10:1 11:1 12:1 13:1 14:1 15:1 16:1 17:1 18:1 19:1 20:1 21:1 22:1 23:1 24:1 25:1 26:1 27:1 28:1 PITCH (INCHES) 1/32, 1/16, 3/32, 1/8, 5/32, 3/16, 7/32, 1/4, 9/32, 5/16, 11/32, 3/8, 13/32, 7/16, 15/32, 1/2, 17/32, 9/16, 19/32, 5/8, 21/32, 11/16, 23/32, 3/4, 25/32, 13/16, 27/32, 7/8, 29/32, 15/16, 31/32, 1 HELIX ANGLE 10° 11° 12° 13° 14° 15° MARLES - WELLER GEARS - HELIX ANGLES, PITCH, & GEAR RATIO CURVES PITCH AND HELIX ANGLE PITCH AND GEAR RATIO O.{Mr Oldham} & Q. GEARS O.{Mr Oldham} & Q. GEARS | ||