Abstract: To provide a reliable, yet resilient, seat for a cutter blade or knife (13) in a rotary milling body (11), the milling body is formed with a bore (21) which intersects the inner wall (19) of a recess (12) in the circumference of the milling body (11). A roll pin is inserted in the bore, retained therein, but projecting over the plane of the wall surface (19). The knife (13) is formed with a longitudinal groove (27), having opposite flat angled side walls (60), which fit around the projecting surface of the roll pin. A holding element (15), fitted into the recess, bears against knife and resiliently clamps it against the roll pin. Preferably, the holding element (15) and the knife (13) are formed with an interengaging projection (41) and recess (42) arrangement.