a lever 50 which extends over the board 43 its outer end carries a vertical hole 51 in which is introduced a detent 52 when the detent 52 reaches the marking holes 53 made on the periphery of the board 43 it can be introduced into the same and lock the lever 50 the marking holes 53 are in angular correspondence with the screws 13 the opening out of the articulated section 3 is then commenced and the collet 17 is placed under a screw 13 as a result of the means contained in the optoelectronic case the board 43 is then fixed to the drum the oblong holes 48 make it possible to freely rotate the board 43 in order to correctly position the collet 17 when tightening is ended it is merely necessary to remove the detent 52 and to rotate the rotary plate 49 which is integral with the lever 50 and carries the handle 1 into the board 43 until the detent 52 can be introduced into another marking hole 53 for placing the collet 17 under another screw 13 the handle 1 has the same offcentering for all the angular positions because the rotary plate 49 is coaxial to the well 12 the board 43 can be replaced by another board with differently positioned reference marking holes 53 in order to make the tool comply with different distributions of the screws 16 or alternatively the holes 53 can be located on a detachable replaceable part fixed to the remainder of the board 43 by a random means which gives the same result the opening out device 45 consists of a motor 54 which drives the external shaft 29 by a not shown transmission 55 and which can comprise gears or a belt the tightening or.