I have just spoken to my original machinist who drilled the locating hole and he has informed me he drilled then reamed the hole with a 3mm ream.
Makes sense as there is the chance that the 3 mm drill can drill undersize.
He has suggested a 3.05 mm hole so that after case hardening that the pin is still a push fit.
I have also discussed the current issue with the crack from the pin to the cam locating hole and he explained that the hole is at the end of the crack and it will not travel any further.
Makes sense as when a windscreen or plastic screen cracks you drill a hole at the end to stop the crack going any further.
If anyone wants to check this guy out visit www.epicycle.com.au
. His name is Pete Smith and he used to run the Ducati Dealer Team in Australia race team in the 1990s.
Thanks for the feedback and input too.