The shaft will be round with a 4mm keyway milled in it to allow motorisation or connection of a hand crank.
I am waiting for the final sample, I have been sourcing and testing parts from a few factories, and am now satisfied with the quality from on supplier, unfortunately I made a couple little change last design cycle and the factory will not mass produce until I approve a sample. Understantable but unfortunately it results in some delays. I am also getting the crank arm cast so lead time on that has delayed things a little as well. I expect the final sample by the end of this month, give me another 6 weeks post then to have it up on my website (figers crossed)