Not only is this a hard to find entry but this one’s in pristine condition still retaining some of its original golden luster from 120 years ago, was most likely on the back of an unused door.
Measures 2-3/4” in dia. Uses a threaded 3/8” spindle that screws into an 11/16” adjustable shank. Threaded entry spindle tapers down to a ¼” standard passage size, designed for a split mortise lock that’s Included with knob.