XC Racer - BB30 Bolt Replacement

During the Whyte 20-CS xc racer build I mentioned that the self extracting bolt looked like it might be damaged and this did indeed turn out to be the case.  When I started to tighten the cranks up to the specified torque the effort dropped off suddenly and it was clear the bolt had pulled through the crank arm. 

The bolt in question can be seen in the diagram below, which is taken from the FSA BB30 Installation manual and can be found at the link below:

https://www.bike-components.de/bedienungsanleitungen/2011/fsa/atb/mtb_bb30_detailed_instructions.pdf

Exploded diagram of the cranks from the FSA Installation Instructions

The self extracting bolt, or BB30 Crank Bolt as FSA refer to it in the figure above, is top hat in section, and the brim of the top hat was the area that had failed.  Usually this type of bolt is steel but this FSA version is a very lightweight alloy, something like ZAMAK, which is light and dimensionally accurate as a material but has a high air content and prone to crumbling, which had happened in this instance.  The Bolt has a 10mm Allen head and the top hat section contacts the crank arm and drives it along the splines of the spindle as the bolt is rotated.  This part was most likely over-torqued causing the in-expensive bolt to fail rather than the much more expensive crank arm.

The old bolt can be seen below on the left next to the new replacement bolt.

The replacement bolt was bought from Triton Cycles, link below.

http://www.tritoncycles.co.uk/components-c9/crank-spares-c186/fsa-bb30-crank-bolt-p5253