Found with locks and plates made by Kenton and by Union Door knob. Kenton plate design shown in 1892 Kenton catalog. Knob attachment based on US patents # 255,858 and #261,604 by O.M. Hidden. The spindle went the outer knob, the serrated end was gripped a U shaped piece. The inner knob was slid over the piece and a screw used to pull the knob tight. Note the end of the spindle and the head of the screw are brass clad.