Abstract: A tube nut wrench having a slotted end for application of a socket member of the wrench laterally to a side of a tube so as to receive the latter into the socket and to allow the socket to be moved axially to receive the tube nut for setting the latter. A reversible air motor is used to rotate the socket member in a reverse direction to register a slot in the socket member with a slot in the end of the wrench to admit the tube at the start of an operation, or to allow withdrawal of the wrench from the tube at the end of an operation, the motor being operable in a forward direction to set the nut. An adapter is provided for engagement with the regular socket member to provide a larger socket for reception of a larger than usual size nut.