An electric tool grinding machine has an electric motor, a grip body, a cover connected to the body, an eccentric block in the cover and driven by the motor, and an airflow generating member attaching on the block. The body has at least one air hole having a first distance relative to an axis of the motor, the cover doesn't have a through hole, the airflow generating member has a bottom plate and a plurality of fan blades, a second distance is between a top edge of the blade and the body, a third distance is between an outer edge of the blade and the cover, the second distance is at least 50% of a longitudinal length of the blade, the third distance is at least 50% of a radial length of the blade, and an outer diameter of the airflow generating member is greater than the first distance.

A centrifugal fan for an electric work machine (1) includes a wall part (136), which radially surrounds a fan main body (5) that includes a blade unit (55) having radially-extending blades (56) on one surface of a disc (51). The wall part is defines a flow path, between an outer-circumferential edge (D1) of the blade unit and an inner surface of the wall part, that directs, in a first direction that is parallel to the first axis, air delivered radially outward from (by) the plurality of blades. The inner diameter (D2) of the blade unit is 45%-60% of the outer diameter (D1) of the blade unit. The outer diameter (D3) of the disc is 80%-95% of the outer diameter of the blade unit. The inner diameter (D4) of the wall part is 110%-120% of the outer diameter of the blade unit.

A centrifugal fan for an electric work machine (1) includes a wall part (136), which radially surrounds a fan main body (5) that includes a blade unit (55) having radially-extending blades (56) on one surface of a disc (51). The wall part is defines a flow path, between an outer-circumferential edge (D1) of the blade unit and an inner surface of the wall part, that directs, in a first direction that is parallel to the first axis, air delivered radially outward from (by) the plurality of blades. The inner diameter (D2) of the blade unit is 45%-60% of the outer diameter (D1) of the blade unit. The outer diameter (D3) of the disc is 80%-95% of the outer diameter of the blade unit. The inner diameter (D4) of the wall part is 110%-120% of the outer diameter of the blade unit.