A rotating combination thrust plate and thrust shaft flange (10), and a thrust bearing assembly (40) incorporating the rotating flange plate combination (10), in which the rotating flange plate combination (10) has a generally cylindrical body portion (22) which has a rotating base surface (24) and a lateral surface (23), a frustoconical body portion (29) which has a frustoconical surface (28), and a bore (12) extending through the cylindrical and frustoconical body portions (22 and 29) and having a first bore section (14) and a second bore section (16) wherein the second bore section (16) is adjacent the rotating base surface (24) and has a smaller diameter then the first bore section (14). The first and second bore sections meet at a junction (18) defining a lip (21) which is designed to support a complimentary lip (42) of a bore shaft (20) thereby restricting the movement of the bore shaft (20) in the direction of thrust in an extruder.