Surgical tools that include a mechanisms for transmitting torque through an angle are disclosed. A surgical tool includes an instrument shaft, a drive shaft, an end effector, a driven shaft, and a coupling member. The instrument shaft is elongated along an instrument shaft axis. The drive shaft is mounted to the instrument shaft for rotation about a drive shaft axis. The end effector is coupled with the instrument shaft so that an orientation of the end effector can be varied relative to the instrument shaft. The driven shaft is coupled with the end effector to articulate a feature of the end effector via rotation of the driven shaft relative to the end effector. The coupling member couples the drive shaft with the driven shaft so that a rate of rotation of the drive shaft and a rate of rotation of the driven shaft about a driven shaft axis are equal.