Hollowtech Crank

[Nealh]

Apart from the drive BB shaft failure everything else is aluminium cranks/spider failures have to agree a silly bit of wax oil won't prevent ali from shearing.
Production faults in casting or lack of bearing maintenance more the likely issue.
Recently replaced a HT BB after noticing/hearing noises from the area, drive side bearing was grinding and some play evident.
The 7th pic of the axle failure looks bad but looking at the ali wear/ gouging on the spiders internal face suggests something else was occurring for a while to cause the failure.

 

[NJS]

Apart from the drive BB shaft failure everything else is aluminium cranks/spider failures have to agree a silly bit of wax oil won't prevent ali from shearing.
Production faults in casting or lack of bearing maintenance more the likely issue.
Recently replaced a HT BB after noticing/hearing noises from the area, drive side bearing was grinding and some play evident.
The 7th pic of the axle failure looks bad but looking at the ali wear/ gouging on the spiders internal face suggests something else was occurring for a while to cause the failure.

Several of those axle shear failures have been definitively identified as having originated at pits caused by corrosion in the open hollow steel shafts.

Preventing that corrosion would prevent those failures. Waxoil coating the interior of those hollow shafts would have prevented the corrosion.

And that was all I suggested.

However, aluminium also corrodes. Place a crystal of road salt on a piece of aluminium and add a drop of water, wait a week and see what happens.

A waxoil coating would also slow down, if not totally prevent, that also.