The cutting head assembly object of the present invention comprises a trimmer line feed mechanism and a trimmer line winding mechanism. A lower cover member coupled to the housing member and has a central opening to hold a ground engaging button member. The ground engaging button member is rotationally engaged to the spool and a lower cover. The upper section of the ground engaging button member and the internal walls of the cover ring have radially and axially extending structures which cooperate with each other to provide a ratcheting and indexing mechanisms that allows controlled rotation of the spool which is constrained from axial movement relative to the head enclosure by biasing the force of a compression spring which also maintains the ground engaging member in an extended position. The winding mechanism allows to manually turn the knob in one direction while the indexing mechanism allows to control rotational increments of the knob to allow the spool to release controlled increments of line when the ground engaging member is bumped against the ground and to stop rotation of the spool during normal running position.