This work deals with investigation of material property changes during metal working – concretely during milling. For eddy current detection, we are using the advanced single chip impedance converter. The device consists of AD5933 impedance converter, voltage controlled current source and MCU. The changes in impedance of a sensing probe are detected by using of four electrodes (couple of voltage, couple of current electrodes). The MBN measurements are performed by us designed device. The MBN device offers MBN measurements for wide range of excitation frequencies. A magnetization coil on a ferrite U – core is connected to an amplifier which powers this part. The MBN signal is sensed by coil placed in U – core gap and it is attached to the sample. The main aim of the work is to obtain information about the scanned surface properties using eddy current and MBN measurements.