A shaft for a needle rocker (not a captive bearing with inner race) has to be in the Rockwell 50 numbers or it will brinnel itself to death, because the individual needle is knife-blade hard and its load per square inch of contact is MUCH higher than a plain bearing.
If you have a good bronze bushing in the rocker, and positive oil feed, the shaft can be much softer and cheaper to make. Except for the oil passages, it could be made from cored shelf stock (common fractional sizes) at a slight oversize and lathed to suit.