An exemplary rotatable joint (100) used for a mechanical device includes a socket (10), a rotatable arm (20), a supporting shaft (13), a fastening member (15), an adjusting member (16), and a resilient module (18). A pivot hole (212) is defined in the rotatable arm. The supporting shaft includes a first shaft portion (130) and a second shaft portion (132). A threaded hole (131) is defined in the first shaft portion and the first shaft portion extends through the pivot hole. The second shaft portion is fixed to the socket. The fastening member includes a threaded portion (152) for engaging in the threaded hole of the supporting shaft. The adjusting member is disposed at the threaded portion of the fastening member. The resilient module is disposed between the rotatable arm and the adjusting member for providing an axial resilient force. The axial resilient force is fine tuned by moving the adjusting member.