15-08-2017, 06:25 AM
For what it may be worth, the Austin 1929 factory drawing published some time ago (but which I cannot now find), gave tolerance as front -.00025, rear +.00025 so the front was originally not a tight fit.
Especially as older bearings had a tolerance range which extended above the nominal
Was it the rigours associated tight assembly which started the lip failure?
Tight assembly does much to quieten bearings, possibly explains why there is no discussion about internal tolerances of now.
I have asked before, but what exact size(s) are Phoenix cranks finished? Nitriding is slightly haphazard if not finally ground. Are the end journals linished? For such precision micrometer needs to be checked against known standard.
Especially as older bearings had a tolerance range which extended above the nominal
Was it the rigours associated tight assembly which started the lip failure?
Tight assembly does much to quieten bearings, possibly explains why there is no discussion about internal tolerances of now.
I have asked before, but what exact size(s) are Phoenix cranks finished? Nitriding is slightly haphazard if not finally ground. Are the end journals linished? For such precision micrometer needs to be checked against known standard.