21-09-2018, 07:27 AM
(20-09-2018, 10:09 AM)steve Davidson Wrote: [quote pid='16376' dateline='1537425541']
Thanks, like you say hand filing of 0.001 is beyond my skill level, maybe lapping on a sheet of glass would be an easier option
[/quote]
I am finding the exchange very confusing with all the repetition, so I will start afresh.
The instructions in the Companion are correctly taken from the Austin Service Journals and as well as the mistake as to which bits get filed the instructions don't make sense.
If a pair of 'Dual Purpose' (Austin's name) or Angular Contact bearings are correctly mounted the housing should be bored parallel (without any relief for one bearing) and the outer ring nut should clamp them firmly in an axial direction (otherwise the pinion would float back and forth).
The matched pairs of bearings originally supplied were specials with the narrow outer rings which must always be mounted in what the bearing companies call back to back, with the raised edges of the inner ring to the outside and the raised edges of the outer ring together. These matched pair bearings were also originally provided with a two thou axial float which was later changed by the factory to a two thou pre-load.
This inch series of angular contact bearings is now usually not available in matched pairs with a set preload but the standard bearing manufacturing tolerances are generally sufficient to work - especially as the original factory setting was either 2 thou float or 2 thou pre load over the life of the car (if you want to, the pair of bearings can be checked for axial setting by clamping the inner and then outer rings and measuring with shims to either set the pre load or float).
Just out of interest the 'Austin Service Journal's mention a change in May 1931 to left hand thread for both the pinion shaft thread and the outer ring
clamping nut or as they call it the distance piece.
Hope this make sense- Cheers, Tony.