Method to check the correct functioning of a tightening tool, such as an industrial screwdriver, placed on a test bench, said bench including, • a plurality of hydraulic brakes (F1-Fn), to which the instrument is associated, suitably controlled by a hydraulic circuit, • each brake being equipped with measurement transducers capable of measuring the torque exerted and the angle of rotation on this brake, connected to an electronic driver card, which also controls the hydraulic circuit, • an electronic processing unit which communicates with the card and which includes an adequate driving program memorized on it capable of regulating the braking capacity of the brakes through the hydraulic circuit according to a predetermined braking torque / angle of rotation curve of the brakes, characterized in that it includes the following steps: a. acquire one or more real tightening curves torque exerted / angle of rotation during one or more tightening performed for example with the tool to be tested, b. elaborate said one or more real curves to make them compatible with the format of the curves that can be inserted in said test bench, c. supply such one or more curves at the input to the test bench and in particular to one or more selected brakes (F1-Fn), d. perform a tightening with the tool to be tested on the one or more selected brakes. said bench including, • a plurality of hydraulic brakes (F1-Fn), to which the instrument is associated, suitably controlled by a hydraulic circuit, • each brake being equipped with measurement transducers capable of measuring the torque exerted and the angle of rotation on this brake, connected to an electronic driver card, which also controls the hydraulic circuit, • an electronic processing unit which communicates with the card and which includes an adequate driving program memorized on it capable of regulating the braking capacity of the brakes through the hydraulic circuit according to a predetermined braking torque / angle of rotation curve of the brakes, • a plurality of hydraulic brakes (F1-Fn), to which the instrument is associated, suitably controlled by a hydraulic circuit, • each brake being equipped with measurement transducers capable of measuring the torque exerted and the angle of rotation on this brake, connected to an electronic driver card, which also controls the hydraulic circuit, • an electronic processing unit which communicates with the card and which includes an adequate driving program memorized on it capable of regulating the braking capacity of the brakes through the hydraulic circuit according to a predetermined braking torque / angle of rotation curve of the brakes, characterized in that it includes the following steps: a. acquire one or more real tightening curves torque exerted / angle of rotation during one or more tightening performed for example with the tool to be tested, b. elaborate said one or more real curves to make them compatible with the format of the curves that can be inserted in said test bench, c. supply such one or more curves at the input to the test bench and in particular to one or more selected brakes (F1-Fn), d. perform a tightening with the tool to be tested on the one or more selected brakes. a. acquire one or more real tightening curves torque exerted / angle of rotation during one or more tightening performed for example with the tool to be tested, b. elaborate said one or more real curves to make them compatible with the format of the curves that can be inserted in said test bench, c. supply such one or more curves at the input to the test bench and in particular to one or more selected brakes (F1-Fn), d. perform a tightening with the tool to be tested on the one or more selected brakes.