A device (1) for measuring a force acting between a machining tool (4) and a work piece in a processing machine is disclosed. It comprises an arrangement of at least two hydrostatic pads (7), wherein the at least two hydrostatic pads are designed to receive and support a mounting part (10) of the machining tool (4), and each hydrostatic pad of the at least two hydrostatic pads (7) presenting a pressure sensor (13), a calculation unit (16) for —reading hydrostatic pad pressure related to the pressure sensors (13) and a constant based on characteristics of each one of the at least two hydrostatic pads (7), —calculating the force by calculating a difference between the products of, for each hydrostatic pad of the at least two hydrostatic pads (7), the hydrostatic pad pressure and the constant, and —indicating the force. Also, a device for monitoring a machining tool and a device for compensating for a deflection of a machining tool when machining a work piece comprising the device are disclosed.