Abstract: A socket for driving a threaded fastener into a material has teeth spaced around a fastener opening. The teeth cut out a counterbore hole that receives the head of the fastener as the fastener threads into the material.

Abstract: A socket for driving a lug nut. The socket may include a tapered external surface which eliminates shoulders which might otherwise exist at the external surface of the socket. The tapered external surface may be formed as a sleeve. In a second implementation, the sleeve may both provide the tapered external surface and may also cover one end of the socket to increase the overall diameter and hence grippability of the socket. The socket may be fabricated from steel, while either of the sleeves may be fabricated from a lighter material such as aluminum or an alloy thereof. The socket may have a chamfer at the internal termination of the wrench surface of the socket to better seat lug nuts having a correspondingly tapered configuration.

Abstract: An improved, high-efficiency wheel lug nut socket is provided for use in racing pits, in order to minimize the time required for race car wheel changeovers. The socket is designed with an inner operating surface including concave surfaces and intervening apex surfaces, dimensioned so as to permit a hexagonal lug nut to be received therein with full clearance between the inner operating surface and the lug nut outer surface. The socket is normally used with a conventional high-speed pneumatic automotive wrench.

Abstract: A joint recognition member is revealed. The joint recognition member includes a joint body formed by a cylinder connected with a polygonal prism. A polygonal hole with a magnet part is set on the cylinder so as to attract driver bits by magnetic force. The device features on that: a narrow neck part with a ring groove is arranged at one end of the cylinder near the polygonal prism. The ring is wrapped around the narrow neck part and outside diameter of the ring is no smaller than that of the cylinder. A protruding ring on the ring is mounted and moved freely in the ring groove. An outer surface of the ring is labeled with words such as size. According to the corresponding polygonal hole, the ring has different shapes and sizes in various colors for fast recognition.

Abstract: A hand tool includes a shaft, at least one affecting portion, and a protection layer. The shaft is like a bar, and can be hold by a hand. The affecting portion connects with the shaft. The affecting portion can grip a specific part which a user wants to control. The protection layer is settled and/or covered on at least one portion of the hand tool surface. The protection layer is lumpy and rough. Because of the protection layer, the hand tool is shake-proof, wear-proof, slip-resistance, and electric insulation.

Abstract: A tool having a body that includes at least one aperture is provided. The aperture has a closed perimeter of side walls and a plurality of spaces. The plurality of spaces include a central space and a plurality of auxiliary spaces disposed radially outward from the central space. Each space is configured to receive a multi-sided component therein. The multi-sided component can be a hexagonal nut or bolt head or other polygonal component.

Abstract: A universal wrench may include a socket including an inner profile contoured to engage outer perimeters of differently-sized generally oval manual handles only when a long axis of the universal receptacle is not parallel to respective long axes of the generally oval manual handles and a handle extending from a base of the universal receptacle. The socket is of elongated form, in that it may be defined by substantially parallel walls spaced a distance apart and comprising the inner profile, said parallel walls being at least about twice as long as the distance. The inner profile may be principally defined by the substantially parallel walls of the socket.

Abstract: A threaded fastener driving tool includes a proximal end portion, a distal driving head, and a torsion zone extending proximally from the driving head, The distal driving head has a central portion and a plurality of driving surfaces. Each pair of adjacent driving surfaces define a driving space therebetween. The driving surfaces and driving spaces are configured to engage a threaded fastener. The torsion zone includes a plurality of helical grooves bounded by non-cutting surfaces, each helical groove in communication with and extending proximally from at least one of the driving spaces. The helical grooves are configured to untwist and cause lengthening of the torsion zone when an input torque applied to the proximal end portion is insufficient to overcome an output resistance torque at the driving head. The torsion zone may comprise a plurality of twisted wires or cables. A method of manufacturing the driving tool is disclosed.

Abstract: A tool for archery broadheads or other fasteners is provided including an engagement end having an aperture, socket or drive feature to accommodate the broadhead or engage a fastener. The tool is constructed at least partially from an elastomeric material. Upon application of a moment to the tool by a user, part of the tool deforms or twists so that indicia elements move relative to one another and output torque or moment information to a user based on the spatial orientation of the indicia elements relative to one another.

Abstract: A socket for a turn-of-nut torque application includes at least one visual indicator for indicating a turn-of-nut position. In a preferred embodiment, a visual indicator is precisely machined into the exterior surface of the elongated body portion of the socket. The visual indicator may correspond with an interior corner of the nut end recess. Several visual indicators may be provided, and each visual indicator may correspond with a different interior corner of the nut end recess. The visual indicator may further comprise a permanent paint, and each additional visual indicator may comprise a different colored permanent paint.

Abstract: A propeller wrench for easily removing and installing boat motor propellers is described. The wrench is equipped with specially sized extensions and socket in order to expedite the job at hand. Up to seven tools are incorporated into the propeller wrench, including tools designed for both Mercury Inboard/Outboard propellers and the Volvo Penta propeller setups, making it easy to use only a single tool to accomplish the entire removal or installation of a boat propeller. The propeller wrench is designed to be universal in nature, and expedite the process of propeller installation and replacement.

Abstract: A wrench is formed with a polygonal first engaging hole that is defined by a plurality of engaging surfaces and that is adapted for engaging a head of a first bolt. Each engaging surface has a pair of plane surface portions and an intermediate surface portion interconnecting the plane surface portions and defining a groove. The grooves of the engaging surfaces collaboratively define a polygonal second engaging hale for engaging a head of a second bolt. The intermediate surface portion of each engaging surface cooperates with the corresponding plane surface portions to form two angular intersections adapted to abut respectively against side surfaces of the head of the second bolt that define a corresponding corner of the head of the second bolt.

Abstract: A hollow shaped socket insert adapter rotatively driven by a single socket driver for tightening, loosing, and removing various sizes of nuts/bolts.

Abstract: A tamper resistant fastener system includes a threaded fastener having a head provided with uniquely formed and arranged engagement teeth for engaging with complimentarily formed teeth on a socket style torque transmitting drive tool. Engagement of the respective sets of teeth on application of torque from the drive tool in one direction advances the fastener, but application of torque from the drive tool is not effective in an opposed direction to remove the fastener.

Abstract: Disclosed is a screw head having a slot (2) in the upper surface of the screw head, an upper peripheral wall (9) of hexalobular planform extending down into the screw head, the upper peripheral wall (9) being parallel or near parallel to the axis of the screw, a sloping transition surface (15) extending downwardly and inwardly with respect to the lower edge of the upper peripheral wall (9), and a tapered recess (11) extending downwardly from the lower edge of the sloping transition surface (15), in which the dimensions of the screw head are such that when the screw head is engaged by a tool (6) having upper (16) and lower engagement (17) sections, there is a ‘stick fit’ between the surface of the tapered recess (11) and the external surface of the lower engagement section (17), and there is no engagement with the sloping transition surface (15).

Abstract: A dual-head tool has a handle with a longitudinal bore extending longitudinally its entire length. A shaft is housed within the bore and may be slid longitudinally to expose either of its two tool heads, but not both simultaneously. A lock arm is pushed down so that it is flush with the shaft and handle and a cam on the lock arm engages a recess in the shaft so that the shaft is firmly held extending out of one side of the handle to allow use of one of the tool heads. The head of the lock arm covers the open end of the bore not in use. A piston biased by a spring engages a keyway in the shaft to prevent the shaft from being removed from the bore.

Abstract: A coaxial connector includes a lip portion on one end thereof and an extension section coaxially extends from the lip portion. The extension section has a tubular portion coaxially mounted thereto and at least one protrusion extends from the outer surface of the tubular portion. A tool for disconnecting and connecting the coaxial connector includes a mounting portion for being mounted to the coaxial connector and the mounting portion has a yield slot defined therein which is located corresponding to the at least one protrusion of the coaxial connector.

Abstract: A socket for driving a fastener, having a damaged head, includes a hole defining an inner peripheral edge. The inner peripheral edge defines a plurality of engaging sides and slots. Each engaging side includes first, second, and third sections. The first section extends from one slot and approaches to a center of the hole, the second section extends from the first section and away from the center of the hole, and the third section extends from the second section and towards and connects to another slot.

Abstract: An adjustable socket tool with a selectively adjustable depth includes a housing having an elongated passage. A fastener socket is attached to a proximal end of the housing for concurrent rotation therewith and includes an interior region in communication with the elongated passage. The adjustable socket further includes an elongated stop pin slidably disposed within the elongated passage and fixed to the housing for concurrent rotation therewith about a longitudinal axis of the stop pin. The stop pin includes a proximal end arranged proximate the fastener socket so as to operably engage a bolt received within the fastener socket.

Abstract: A wrench drive socket having jaws, actuated by a cam mechanism, facilitating the accommodation of a range of faceted work pieces is provided wherein adjustment of the distance between the jaws having V-shaped grips is accomplished by rotation of a knurled adjustment collar circumferentially disposed around a socket sleeve and fixed to an internally positioned jaw guide, the rotation of the jaw guide selectably positioning cam followers on the jaws against arch shaped cam profiles fashioned along the inside circumference of the socket sleeve, the sleeve being fixed to a centrally disposed socket body having an engaging hole to receive a drive shaft of a wrench such as a ratchet wrench. The adjustable drive socket provides advantages over the prior art including simplified construction, convenience of use, durability, effectiveness, and cost and weight reduction through the elimination of a plurality of sockets having fixed sizes.

Abstract: An improved, high-efficiency wheel lug nut socket is provided for use in racing pits, in order to minimize the time required for race car wheel changeovers. The socket is designed with an inner operating surface including concave surfaces and intervening apex surfaces, dimensioned so as to permit a hexagonal lug nut to be received therein with full clearance between the inner operating surface and the lug nut outer surface. The socket is normally used with a conventional high-speed pneumatic automotive wrench.

Abstract: An adapter encircles and locks around nut members of pipe unions or nuts made up on fasteners, or cylindrical members, and engages the nut member or cylindrical member in locking contact. The adapter has strike surfaces which allow the nut member or cylindrical member to be tightened or loosened by a hammering means, such as a hammer, mallet or sledge hammer. Thus, in the case of a pipe union, the device temporarily converts a nut union to a hammer union. The apparatus is configured to facilitate attachment of the device in tight situations, such as attaching the device to the nut member of a pipe union, or to a fitting, within a piping manifold having closely spaced parallel pipelines.

Abstract: A socket assembly includes a body having a driving portion to be driven by a driving tool and a transmission portion for driving a fastener. The transmission portion includes a first end and a second end spaced from the first end along a longitudinal axis. The first end of the transmission portion is connected to the driving portion. A sleeve is mounted around the second end of the transmission portion. A jacket is mounted around the transmission portion and the outer periphery of the sleeve. The transmission portion of the body and an outer periphery of the sleeve are visible through outer and inner peripheries of the jacket.

Abstract: A tool for assembling and disassembling the front and the rear wheel axle of a motorcycle includes a nut holding base having one side formed with a ratchet recessed groove provided therein with a projecting member having a hexagonal recessed groove formed in the interior. The nut holding base has another side provided with an extension projecting post having an interior bored with a square hole communicating with the hexagonal recessed groove. A connecting holder to be assembled on the nut holding base has one side formed with a hexagonal projecting connector matching with the hexagonal recessed groove of the nut holding base and having an interior disposed with a square insert hole. The connecting holder has another side formed with a hexagonal recessed groove provided with a projecting member bored in therein with an insert hole that communicates with the square insert hole.

Abstract: The invention relates to a two-part wrench for engaging and rotating a fastening element. A first part consists of a torque-applying portion and the second part is separable from the first part. When disassembled, the wrench has open jaws that can engage a fastening element. The two parts of the wrench may then be assembled around the fastening element to form a closed-loop (or essentially closed loop) ring wrench to apply torque.

Abstract: A fastener tool assembly for installing breakaway torque nuts includes a socket having a first end attachable to a driver of a fastening tool. A second end of the socket operably engages a detachable wrenching ring of a breakaway torque nut. A window is formed in a sidewall of the socket, sized and configured to permit at least one wrenching ring to pass therethrough. A catch permits insertion of the wrenching ring into the socket, but prevents the detached wrenching ring from freely falling out of the open end of the socket. A sleeve associated with the window selectively permits passage of one or more detached wrenching rings through the window, or prevents passage of the detached wrenching rings therethrough.

Abstract: A metric and English socket wrench is rotatable about an axis, and includes an inner peripheral surface. The inner peripheral surface has first engaging portions, and second engaging portions arranged alternately with the first engaging portions. Each of the first engaging portions has two first engaging surfaces interconnected to form a V-shape. A first apex is disposed between the two first engaging surfaces, and is spaced apart from the axis by a first distance. Each of the second engaging portions has two second engaging surfaces interconnected to form a V-shape. A second apex is disposed between the two second engaging surface, and is spaced apart from the axis by a second distance. Ratio of the first distance to the second distance is more than 0.94 and less than 1.06.

Abstract: A tool head includes a connecting component, a driving component, and a spacer. The connecting component includes a receiving end defining a tight-fit section and a non tight-fit section. The driving component is insertably fitted in the receiving end of the connecting component, and includes a body defining first and second engaging sections. The second engaging section is received in the non tight-fit section. The spacer includes first and second tight-fit edges, with the first engaging section tightly fit in the tight-fit section by the spacer, with the first tight-fit edge tightly abutting against a wall delimiting the tight-fit section and the second tight-fit edge tightly abutting against a wall delimiting first engaging section, respectively.

Abstract: A tool may loosen seized bolts by sending shock waves into the bolt shank and thread areas via axial blows with a pneumatic hammer on the center of the bolt head prior to removal. The tool may allow impacts to be centered on the bolt head without damaging the bolt head or without worry of the bit jumping off the bolt. The tool may be comprised of a separate driver and one or more sockets.

Abstract: A damaged fastener extractor is provided with a body defining generally cylindrical coordinates ?, Z and R about an axis and having a rear body portion communicating with a front body portion. The rear body portion has an outer surface shaped to be engaged by a tool to be used in rotating the body circumferentially about the axis and sized to present a working outer dimension OD to said tool. The front body portion has a front terminus and an inner surface in which the front terminus is oriented substantially perpendicular to the axis and provides a generally circular receiving aperture communicating with the inner surface. The inner surface is shaped to engage a damaged fastener to be extracted and sized to present a working inner diameter ID to the damaged fastener.

Abstract: A hand tool includes a shaft, at least one affecting portion, and a protection layer. The shaft is like a bar, and can be hold by a hand. The affecting portion connects with the shaft. The affecting portion can grip a specific part which a user wants to control. The protection layer is settled and/or covered on at least one portion of the hand tool surface. The protection layer is lumpy and rough. Because of the protection layer, the hand tool is shake-proof, wear-proof, slip-resistance, and electric insulation.

Abstract: An adapter encircles and locks around nut members of pipe unions or nuts made up on fasteners, and engages the nut member in locking contact. The adapter has strike surfaces which allow the nut member to be tightened or loosened by a hammering means, such as a hammer, mallet or sledge hammer. Thus, in the case of a pipe union, the device temporarily converts a nut union to a hammer union. The apparatus is configured to facilitate attachment of the device in tight situations, such as attaching the device to the nut member of a pipe union on a piping manifold having closely spaced parallel pipelines.

Abstract: A tool for torquing a regulator onto a cylinder of a portable cylinder assembly. The tool includes a nut and a socket. The nut is configured to fit around a body of a regulator of a portable cylinder assembly. As such, the nut has a first set of grooves that avoids one or more valve assemblies on the body of the regulator. The socket has a cavity extending therethrough such that the cavity consists of three sections: a top section, a middle section and a bottom section. The top section of the socket is configured to be coupled to a device that applies a torque force on the socket. The middle section of the socket is configured to avoid a case of the regulator which is disposed above the body of the regulator. The bottom section of the socket is configured to be coupled to the nut.

Abstract: A wrench socket for use on fasteners such as pipework fittings where closed pipework or other obstructions would normally prevent the use of a ring wrench or closed sockets has a plurality of swivel arms pivotally mounted to a socket main body. The swivel jaws can be opened and closed as required around pipework and the fastener. Formations on the swivel arms align with one another when the swivel arms are closed allowing engagement by a drive bar that locks the swivel arms together. The swivel arms cooperate with the socket main body to define a polygonal fastener receiving aperture. The socket main body can be made thin profile to allow the wrench socket to be used in close proximity to obstructions that would prevent the operation of prior art wrenches and wrench sockets.

Abstract: A ratchet wrench includes a handle and a pawl is pivotably connected to the handle. The pawl is selectively engaged with a positioning unit in the handle. A ratchet wheel has a through hole defined through the center portion thereof and the ratchet teeth of the ratchet wheel are engaged with the engaging teeth of the pawl. Two clamp members are inserted in the through hole of the ratchet wheel and each have an extension. Each extension has a slot defined in top and bottom thereof. The two extensions extend toward opposite directions. Two ring-shaped covers are respectively connected to the top and the bottom of the ratchet wheel and each cover has two openings defined in the underside thereof. The extensions extend through the openings. Pins extend through the covers and are engaged with the slots. The clamp members are movable to clamp objects of different sizes.

Abstract: A meshing gyration tool comprising: a socket base; a socket clearance hole inside the socket base and surrounded by three first gripping surfaces, three second gripping surfaces and six third gripping surfaces for development of edge planes around the socket clearance hole wherein the third gripping surface is located between the first gripping surface and the second gripping surface for circular permutation of first gripping surface, third gripping surface and second gripping surface. The first gripping surface is a cambered surface. The second gripping surface is an angled surface consisting of two adjoining planes which form an obtuse angle. As such, the tool facilitates not only normally driving a nut or a bolt head but also screwing or unscrewing the nut or the bolt head with edges or corners worn out or damaged and further promotes overall convenience, practicability and market competitiveness.

Abstract: A nutdriver that includes a socket configured to receive and engage a hex nut to rotate the hex nut relative to a threaded rod. The socket includes a socket opening. The nutdriver further includes a shank including a first end, a second end, and a shank aperture that extends through the first end and the second end of the shank. The nutdriver further includes a handle including a front end, a back end, and a handle aperture that extends through the front end and the back end of the handle, and the second end of the shank is coupled to the handle for co-rotation. The socket opening, the shank aperture, and the handle aperture are aligned and in communication to allow the threaded rod to extend through the socket opening, the shank aperture, the handle aperture, and beyond the back end of the handle while the socket rotates the hex nut.

Abstract: A socket includes a body having first and second ends and defining a longitudinal axis, a receptacle formed in the first end of the body, and an aperture in the body positioned between the first and second ends. An interior of the receptacle is visible through the aperture from a location exterior of the socket.

Abstract: A socket includes a plurality of protrusions circumferentially disposed around a circular top opening in a top portion of the socket, whereby upon insertion of a driving (or coupling) shaft of a spanner with square head portion into the square hole in the socket, the square head portion of the driving shaft will be respectively biased or thrusted by the protrusions and then smoothly guided or slid through a sloping surface tapered downwardly radially from the circular opening into the square hole for quickly coupling the driving shaft of the spanner with the square hole in the socket. A socket further includes plural bottom protrusions disposed around a circular bottom opening in a bottom portion of the socket, and eighteen faces formed in a hexagonal bottom hole of the socket for helping a quick coupling of a nut or bolt into the bottom hole of the socket.

Abstract: A driving device includes a driving shank, a magnetic member mounted in the driving shank, a stop ring secured in the driving shank to stop the magnetic member, and an elastic member biased between the driving shank and the magnetic member. The driving shank has a first end provided with a mounting post and a second end formed with a mounting hole and a receiving chamber. The stop ring has an inner wall formed with a through hole and an outer wall provided with a toothed portion engaging a peripheral wall of the receiving chamber. The magnetic member has a peripheral wall formed with a stop flange that is movable to abut the stop ring. Thus, the elastic member provides a buffering effect to the magnetic member to reduce the pressure applied on the magnetic member.

Abstract: A tool for torquing a regulator onto a cylinder of a portable cylinder assembly. The tool includes a nut and a socket. The nut is configured to fit around a body of a regulator of a portable cylinder assembly. As such, the nut has a first set of grooves that avoids one or more valve assemblies on the body of the regulator. The socket has a cavity extending therethrough such that the cavity consists of three sections: a top section, a middle section and a bottom section. The top section of the socket is configured to be coupled to a device that applies a torque force on the socket. The middle section of the socket is configured to avoid a case of the regulator which is disposed above the body of the regulator. The bottom section of the socket is configured to be coupled to the nut.

Abstract: A socket wrench in which a supporting hole is formed in a drive disposed at an operating handle, and a steel ball pressed by a coiled spring is movably engaged with the supporting hole. A recess part for allowing the steel ball to partly engage therein is formed in an inner wall of an assembling hole of a wrench body for allowing the drive to engage therein. A connecting hole engageable with a polygonal head part of a bolt to be operated is formed in the wrench body in such a manner as to be coaxial with the drive. The recess part has a pair of contacting walls for the steel ball to contact therewith, the pair of contacting walls being disposed in mutually intersecting directions.

Abstract: An automated driver for tightening a fastener bolt includes a housing body including a handle. A chuck is rotatably connected to the housing body. An actuation system is operatively connected to the chuck for rotating the chuck. A tool element is held by the chuck, the tool element configured to engage the fastener bolt. An alignment tool is connected to the chuck. The alignment tool includes a chuck receiving portion having an opening extending therethrough in which the chuck is located and a bit receiving portion having an opening extending therethrough in which the tool element is located. An end of the tool element extends beyond an end of the bit receiving portion.

Abstract: An open wrench includes a handle which is flat relative to a horizontal plane and a driving head is connected to the head. The driving head has a clamping opening with an opening communicating therewith. The driving head has two flat portions located on top and bottom of the driving head respectively and the flat portions each have an outer face, an inner face and a recess, all of which are located around the clamping opening and arranged in U shape. The inner face is located close to the clamping opening and the outer face is located close to the inner face. The outer face is raised, relative to the horizontal plane, from the mediate portion thereof and toward two ends of the outer face so as to define an inclined angle between the outer face and the horizontal plane.

Abstract: In an embodiment of the present invention, a socket device comprises a sleeve portion for engaging the rotatable driveshaft and a socket portion for use with an impact hammer. The sleeve portion further comprises opposing openings to engage a locking mechanism, such as a pin-lock, nut and bolt, cotter pin, or other locking device appreciated by those with skill in the art.

Abstract: A socket assembly is provided for receiving and retaining a head of a fastener. The socket assembly includes a socket body having a longitudinal interior chamber defined by interior walls. The interior chamber extends axially within the socket body to a receiving end of the socket body. The interior walls of the interior chamber are configured to a shape of the head of a fastener for receiving the head of the fastener at the receiving end. A magnet is disposed within the interior of the socket body. The magnet is selectively movable in an axial direction within the interior chamber of the of the socket body. A fastening member is radially engaged to the socket body. The fastening member is configured to releasably secure the magnet within the socket body at a selected axial position in relation to the head of the fastener inserted within the receiving end.

Abstract: An open-end wrench includes a jaw portion having two engaging portions and an opening between the engaging portions. Each engaging portion includes a driving face having a tip. A corner is formed between a bottom end of the opening and each driving face. A first length is defined between the bottom end in a direction perpendicular to an imaginary line passing through the tips. A spacing between the tips is larger than 0.95 times the first length and smaller than 1.05 times the first length. Two corners of a fastener received in the opening are located on the imaginary line and flush with the tips. Each engaging portion has a width at an associated corner in a direction perpendicular to an associated driving face. The width is the maximum distance from each driving face to an outer surface of the associated engaging portion. The width is larger than 0.2975 times a width between two parallel sides of the fastener and smaller than 0.4025 times the width of the fastener.

Abstract: A grasping device comprising a grasping assembly coupled to a shaft adapted to fit into a drill chuck is described. Embodiments of the grasping device are capable of grasping objects such as a screw head, a bolt head, a hex nut, a wing nut, a hook, or other irregularly shaped objects, so that such objects can be turned by an electric drill, lathe, or similar machine tool.

Abstract: A close fitting structure of a sleeve tool is provided. A through-hole is formed to penetrate a sidewall of the sleeve tool. The close fitting structure includes a body. Sharp engaging teeth are disposed at a front end of the body. The close fitting structure is received in the through-hole of the sleeve tool and adapted to move forward and backward spirally. The close fitting structure is inserted deep into the sleeve tool, such that the sharp engaging teeth disposed at the front end of the body and a nut mesh in a close-fitting manner. Accordingly, the close fitting structure enables the sleeve tool and the nut to mesh efficiently and to be loosened and tightened easily and in a slide-free manner.

Abstract: A design for a rotary drive both for a tool and for a workpiece to be rotationally driven is proposed. This rotary drive design contains a cylindrical basic shape which deviates from a circular cylindrical shape. The contour or the cross section through this basic shape has a plurality of rounded projections and rounded recesses arranged between said projections. The projections tangentially touch a circle having a maximum radius, while the recesses, for their part, tangentially touch a circle having a minimum radius. Deviating from this cylindrical basic shape, in the regions between the projections are configured conical surfaces, which are not instrumental in the transmission of torques, but take care of centering and alignment between the tool and the workpiece.