Three Part Spindle for Antique / Vintage Doorknobs

These spindles are made of three separate triangular pieces that fit together to form a square. I have a wire holding the pieces together for the photo.  One doorknob would be pinned to the spindle and the pin is held in place by the collar of the rosette.  The other doorknob has a set screw that presses down on the assembly, expanding it so the doorknob will not come off.  I’ve included a photo of what the inside of the doorknob shaft for these spindles looks like.

Standard 5/16” square x 4-1/2” long