Improved kit for orthopedics, preferably for osteosynthesis, comprising an internal mechanical fixing system which includes a plate to be mounted straddling two bone fragments to be joined (7', 7") and at least two, preferably at least four, fixing screws for fixing the plate to said two bone fragments (7', 7"), wherein: - said plate consists of a plate made of biocompatible metal material and has a thickness of about 0.5 - 4mm, said plate being provided with at least two, preferably at least four, conical through holes whose inner walls are obtained with at least one surface finishing mechanical operation, - each of said at least two fixing screws has a head and a self-tapping stem, and wherein each of said at least two fixing screws: - comprises a conical collar which is interposed between said head and said self-tapping stem and is configured to define a conical coupling within a corresponding conical through hole of the plate, the head presenting on its upper surface a recessed and shaped mark for the coupling by the, at least partial, shape coupling, of the tip of a screwing tool and said head also presenting on its external side wall a thread for the engagement of a gripping tool, - is configured so that, when its conical collar is inserted into a corresponding conical through hole of the plate, said head protrudes outwards with respect to said plate, - comprises a flange connecting the head with the collar, said flange being configured to be spaced with respect to the outer surface of the plate when the conical collar of the fixing screw is inserted within a conical through hole of the plate itself. - said plate consists of a plate made of biocompatible metal material and has a thickness of about 0.5 - 4mm, said plate being provided with at least two, preferably at least four, conical through holes whose inner walls are obtained with at least one surface finishing mechanical operation, - each of said at least two fixing screws has a head and a self-tapping stem, and wherein each of said at least two fixing screws: - comprises a conical collar which is interposed between said head and said self-tapping stem and is configured to define a conical coupling within a corresponding conical through hole of the plate, the head presenting on its upper surface a recessed and shaped mark for the coupling by the, at least partial, shape coupling, of the tip of a screwing tool and said head also presenting on its external side wall a thread for the engagement of a gripping tool, - is configured so that, when its conical collar is inserted into a corresponding conical through hole of the plate, said head protrudes outwards with respect to said plate, - comprises a flange connecting the head with the collar, said flange being configured to be spaced with respect to the outer surface of the plate when the conical collar of the fixing screw is inserted within a conical through hole of the plate itself. - comprises a conical collar which is interposed between said head and said self-tapping stem and is configured to define a conical coupling within a corresponding conical through hole of the plate, the head presenting on its upper surface a recessed and shaped mark for the coupling by the, at least partial, shape coupling, of the tip of a screwing tool and said head also presenting on its external side wall a thread for the engagement of a gripping tool, - is configured so that, when its conical collar is inserted into a corresponding conical through hole of the plate, said head protrudes outwards with respect to said plate, - comprises a flange connecting the head with the collar, said flange being configured to be spaced with respect to the outer surface of the plate when the conical collar of the fixing screw is inserted within a conical through hole of the plate itself.