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).
Circular letter detailing the use of Gargoyle Hypoid Gear Lubricant for new axle designs.
| Identifier | ExFiles\Box 145\1\ scan0184 | |
| Date | 1st March 1937 guessed | |
| For distribution to V.O.C. Ltd. Sales Staff Attachment to Circular Letter B.1469. GARGOYLE HYPOID GEAR LUBRICANT Recent technical developments, particularly with certain motor cars of American design, have brought about the need for a new back axle lubricant having exceptional Extreme Pressure value. This is mainly due to the increased use of Hypoid Gears of new design on some 1937 models of well known cars, now making their appearance in this country. The following makes of cars will be fitted with such Hypoid Gears:- BUICK, Models 40 & 60, 1937. CADILLAC, Model 60, 1937. CHEVROLET, 1937 Models. CHRYSLER, 1937 Models. DODGE, 1937 & 1936 Models. LA{L. A. Archer} SALLE, 1937 Models. OLDSMOBILE, 1937 Models. PACKARD, 1937 Models. PONTIAC, 1937 Models. STUDEBAKER, 1937 Models. The main objective in this axle design is that it permits a lower arrangement of the propeller shaft and a low floor level inside the car, without the tunnel interference, thus giving greater comfort for passengers. The new type Hypoid gears although somewhat similar to the spiral bevel arrangement place the driving pinions several inches below the centre line of the crown wheel, which introduces a different gear tooth shape and somewhat steeper tooth angularity, which results in materially higher pressures, and additional sliding contact. This creates a much more difficult lubrication problem, as apart from the high tooth loading of the gears, the increased sliding and rubbing motion between the gear teeth necessitates the use of a special oil of unusual film strength. Gargoyle Hypoid Gear Lubricant has been developed to meet the most severe conditions of operation. The usual precaution of avoiding mixing Extreme Pressure lubricants should be stressed with equal insistance with Hypoid Gear Lubricants. The axle drainage periods for Hypoid Gear Lubricant are the same as for Mobiloil EP{G. Eric Platford - Chief Quality Engineer}, namely, every 5000 miles, but owing to its special properties, care should be exercised that this mileage is not exceeded. The milder form of compound used in Mobiloil EP{G. Eric Platford - Chief Quality Engineer} gives the necessary protection to the axle gears where this grade is recommended, and will give superior service for these units. (Cont'd) | ||