The Z axis screw and head stock connection assembly were originally designed to be two pieces, a a nut with a spigot which is inserted into a socket of the block which connects to the back of the vertical slide. except for the drilling and taping, this was made on the lathe using a 4 jaw chuck. The nut in the picture was secured to the table using one of the t slots and a parallel as a spacer to keep it from flipping into the slot.
