Abstract: A machine tool has a spindle head pivotable through 180 degrees and having a spindle rotatably mounted in its housing. As a result of the pivoting movement, the spindle head can be shifted from a vertical to a horizontal working position. The spindle head has a toolholder and an axially displaceable tension rod. Through the tension rod runs a coolant bore extending into the working zone of the clamped tool. The coolant bore is connected to a line in a transfer piston displaceable in the spindle-head housing. The coolant bore and the transfer piston line are constantly in communication so that coolant flows uninterruptedly during displacement of the transfer piston. The line communicates with a coolant supply system. The coolant can be conveyed into the working zone of the tool in any position of the tool spindle and without any appreciable increase in size of the spindle head.