The method includes a step of applying glue including carrying out with a pad printing machine a sequence of steps in which is driven a transfer pad from a glue taking position to an applying position in which the distal surface of the transfer pad is in contact with one surface of one component of the tool and in which is simultaneously driven another transfer pad from a glue taking position to an applying position in which the distal surface of the another transfer pad is in contact with one surface of another component of the tool, whereby the glue is applied simultaneously to the one surface of the one component and to the one surface of the another component.