Twist pin z-axis interconnectors are assembled in columns of aligned vias in stacked printed circuit boards of a circuit module in automated assembly cycles. Each assembly cycle involves singulating a single twist pin from a plurality of twist pins, inserting the twist pin into the via column, gripping a leader portion of the twist pin, pulling the gripped leader portion until a connection portion moves into contact with the vias of the column, severing the leader portion from the connection portion, extracting the severed leader portion, and automatically repeating assembly cycles until interconnectors have been assembled into a substantial majority of the via columns of the circuit module.