A ratchet tool includes a head and a handle extends from a first end of the head and an extension rod is removably connected to a second end of the head. A connection member is connected to the head and includes a slot in which two blocks are movably received therein. Each block includes a clamping face so as to clamp a thread forming tap therebetween. A cover has a hole defined centrally therethrough and two guide ways are defined through the cover. Two pins are connected to the two blocks and slidably extend through the two guide ways. When rotating the head, the two blocks are moved toward to clamp the thread forming tap which is rotated with the rotation of the head. An adapter is connected the head and located opposite to the connection member. The adapter is connected with socket or bit.