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).
The mileage and wear of an experimental bone grey fibre rubbing block and AS tungsten points.
| Identifier | ExFiles\Box 69\1\ scan0379 | |
| Date | 19th June 1925 | |
| X4646 EFC. 19.6.25. WB.{Mr Brazier/Mr Bell}22. X.2894. X.4646. BONE GREY FIBRE RUBBING BLOCK (1ST SAMPLE) AND AS TUNGSTEN POINTS OFF 6-GII. The total mileage of these two experimental items is as follows . Bone grey fibre block 12,239 miles. AS tungsten points 15,853 " The condition of the rubbing block after this mileage was observed to be good, and after measurement the max. wear was found to be .004" This wear is much less than that recorded (for a smaller mileage) of the 2nd. sample bone grey fibre blocks particularly the one (2E) off 8-GIII. The tungsten points have not been reported troublesome at all throughout the run, their present condition being as follows :- (See WA.{Mr Wallis}111) Screw point. Worn down about 50% and pitted the surface being observed to be oxidised. Lever point. Hardly worn at all, the surface being much the same as the screw point. The only advantage with tungsten appears to be due to the fact that the metal does not flow so readily and form large pips and cavities as with platinum, which means a longer life of the points. HEW. | ||