You'd need the tooling or
at least the engineering blue prints. Do you mean the agitator shaft, wash basket post, or the spin tube?
The base plate, or superstructure is a heavy stamped piece. The center post is integral with the inner tub basket. The outer tub mounts to the base plate, and is supported by three beefy suspension rods anchored to the top of the cabinet with three rubber ball snubbers, two at the front, one rear center. The spin tube is of turned, hardened, and polished high quality steel, like a front drive car drive axle.
The transmission and motor mount on the underside of the base plate. The agitator shaft and spin tube run up through the wash basket. Oilite bearings ride between them of course. The clutch is at the base of the spin tube below the base plate.