Save the Snark, I am immune to 'dismissive' and 'marginalizing'
No offence was intended. I do apologise. The main reason for posting was to know if there is any news on the search for other examples of the off-centre counter bore.
By the way, curious about how a splined joint would work I think the helical shape (if that is what it is) serves to screw the joint together by action of shaft torque and so resisting shaft tension.