the bearings or roller elements fitted on the inside of the longitudinal passage are kept at a distance that has a length that is greater than the height of the longitudinal rail which allows for the inclination of the handle towards the front or back and being in an operational cutting position or in a non operational position at the lower end of the handle there is a longitudinal guide for the interchangeable attachment of the of the blade holder pieces that have a slot to enable them to be held in an assembly position as will be described below clearly the longitudinal guide of the handle and the blade holder pieces have similar and suitable sections to enable their coupling in a single position and without being able to turn sideways in the lower part the handle has a transversal housing into which a retaining bolt is fitted for the blade holder part said bolt can be moved manually and without any tools at all from an operating position in which the it is partially housed in the groove of the blade holder part establishing its fixing and a non operating position in which the blade holder piece is free allowing for the dismantling of the handle in this way the replacement of the blade holder pieces for another that is more suitable or in a better condition can be carried out in a quick easy and convenient manner the stated retention bolt meets a thrust spring that holds it in the operating position or that for the fixing of the blade holder piece when the user stops manually activating the retention bolt after having placed or replaced the blade holder piece the stated spring is in charge of returning the bolt of the.