Fluted Mortice Door Knob 3D model is available on CGTrader for $6. Original author: Polygate2. Specs: 3282 polys, 3139 verts.
OBJ (OBJ, filesize: 72.6 KB), BLEND (Blender, filesize: 148 KB), 3DS (3D Studio, filesize: 38.4 KB), C4D (Cinema 4D, filesize: 132 KB), FBX (Autodesk FBX, filesize: 151 KB), MAX (Autodesk 3ds Max, filesize: 2.98 MB), MA (Autodesk Maya, filesize: 119 KB), MEL (Maya Mel Script, filesize: 119 KB)