A rotating member of the present disclosure mainly includes ceramics and includes a first through-hole into which a shaft is inserted and a second through-hole into which a key protruding from an outer peripheral surface of the shaft or a solid lubricant in direct or indirect sliding contact with the outer peripheral surface of the shaft is inserted. The second through-hole is a polygonal shape if viewed in an axial direction of the first through-hole and includes a notch part extending along the axial direction at at least one corner.

Screw elements, extrusion apparatus, and methods of manufacturing honeycomb bodies are described herein. A segment for a ceramic batch screw extruder machine has at least one pump and mix screw element. The pump and mix screw element has a pitch, a diameter, and a pitch to diameter ratio of 0.8 to 2.6.