Abstract: An attaching construction includes a first member having a circular tubular welding portion at a distal end and, at a rear end thereof, a holding portion which is integral with the welding portion. The attaching construction includes a second member having an annular first positioning rib, and an annular second positioning rib inside the first positioning rib. The welding portion is positioned within the first positioning rib, and the welding portion is friction welded in place within the first positioning rib while the first member is rotated.

Abstract: A hole in a metal workpiece is filled by friction plug welding. The weld between the workpiece and the plug is reinforced by a weld land in the workpiece that surrounds one end of the plug. The weld land is formed by extruding a portion of the plug into a cavity in an anvil used in the welding process.

Abstract: A hydrogen supplying apparatus equipped with a hydrogen separation membrane and a catalyst plate, which is made by forming a catalyst layer on a metal plate, wherein the metal material of the membrane is different in hardness from that of the catalyst plate. A method of producing the hydrogen supplying apparatus, which comprises: bonding a catalyst plate and a hydrogen separation membrane to each other, by friction-stir welding, wherein a welding tool is pressed towards only one of the membrane and catalyst plate, forming a reaction layer between the membrane and the catalyst plate by the frictional heat, and forming ripples in the welded interface.

Abstract: In a friction stir welding method for friction stirring and welding a material by using a rotating tool having a shoulder and a pin at a front portion of a shaft portion and ejecting a cooling agent from a cooling nozzle to the tool to be cooled thereby, the cooling agent is ejected to a middle portion in an axial direction of the tool to thereby prevent thermal expansion in an axial direction of the tool.

Abstract: There is provided a method for fabricating a dual alloy structure that may in turn be machined to fabricate a rotary component such as an impeller for use in a gas turbine engine. The method provides a first titanium alloy and a second titanium alloy. The first titanium alloy displays characteristics, such as high strength, suitable for application in the bore area of an impeller. The second titanium alloy displays characteristics, such as high temperature creep resistance, suitable for use in the outer radial area of an impeller. A bore subelement is fabricated from the first titanium alloy. A body subelement is fabricated from the second titanium alloy. The bore subelement and body subelement are joined by inertia welding at a common welding surface. Each subelement and/or the resulting welded structure is heat treated to achieve a desired microstructure.

Abstract: In a link rod manufacturing method, a bracket material (14) having a ring portion and a mounting projection (15) is made by extrusion molding a material at the length corresponding to a plurality of brackets. On a forward end of the mounting projection (15), an engaging projection (17) with upper and lower steps (7a, 7a) is formed. An arm (2) is made by extrusion molding and regular-size cutting a material in a substantially I-shaped configuration which has a pair of first and second walls (20, 21) parallel extending on upper and lower sides and a third wall (22) crossing at a right angle and connecting these walls. A notch (23) is formed on an end of the third wall (22). When the engaging projection (17) is engaged with the notch (23), each of ends of the first and second walls (20, 21) on the side of ends 2a of the arm 2 is fitted onto the step (7a, 7a) and butted against a vertical wall (17b).

Abstract: In one embodiment, a holding fixture is disclosed for locating and stabilizing substantially identical repeated units during joining of the repeated units. In another embodiment, a method is disclosed for manufacturing a structure comprising substantially identical repeated units. In still another embodiment, a welded structure is provided comprising a plurality of welded together substantially identical repeated units.

Abstract: A portable friction forge welder that applies a direct rotational load to workpieces via a rotational actuator and a direct axial load to workpieces via an axial actuator, where the rotational actuator and the axial actuator have separate and independent power sources. The portable friction forge welder relies on a stored energy linear axial actuator or a center-hole hydraulic axial actuator to achieve high axial forces and a high torque, low rotational velocity to achieve rotational forces, enabling the welder to achieve higher quality welds using larger diameter workpieces than conventional portable friction welders. By applying a high axial force between workpieces prior to high torque rotation of the workpieces results in improved quality welds. A unique clamping device maintains a fixed positional relationship between the workpieces and includes a unique shroud that enables friction welds under a positive pressure inert atmosphere.

Abstract: A method of forming a metallic container includes the steps of providing body and lid portions, placing the body and lid portions together, keeping portions of the body and lid portions in contact with one another, and reciprocally rotating the lid portion with respect to the body portion, thereby generating frictional heat and forming a friction weld therebetween. An apparatus for attaching the lid and body portions of a metallic container includes a base to support the body, a support assembly to support a flange of the body, and a sonitrode for contacting a flange of the lid, wherein the flanges of the lid and body are held together between the support assembly and the sonitrode. A motor reciprocally rotates the sonitrode relative to the support assembly, thereby moving the flanges relative one another to generate frictional heat and create a friction weld therebetween.

Abstract: A rotary friction welding machine and method is disclosed. The rotary friction welding machine has a first rotating spindle and a second non-rotating spindle, where a first component of the components being connected to one another is positioned on the first spindle and a second component of the components being connected to one another is positioned on the second spindle. Several flywheel mass bodies are positioned on the rotary friction welding machine, where the flywheel mass bodies cooperate with the first rotating spindle such that at least one of these flywheel mass bodies can be brought out of operating engagement or into operating engagement with the first rotating spindle, where both the flywheel mass bodies that are in operating engagement with the first rotating spindle and the flywheel mass bodies that are out of operating engagement with the first rotating spindle are positioned on the rotary friction welding machine.

Abstract: Method and apparatus are disclosed wherein a hydroformed part remains in a hydroforming die cavity under hydroforming pressure while an attachable fastener nut is operated to pierce and form a collar in the part by forced insertion of the nut into the part and wherein the nut is fastened to the collar by friction welding, friction skip welding or mechanical locking depending on the form of the fastener nut.

Abstract: A gimbaled-shoulder friction stir welding tool includes a pin and first and second annular shoulders coupled to the pin. At least one of the annular shoulders is coupled to the pin for gimbaled motion with respect thereto as the tool is rotated by a friction stir welding apparatus.

Abstract: A friction-stir welding apparatus includes a friction-stir welding tool, a spindle on which the tool is located, bearings supporting the spindle for rotational movement, and a heat sink that is mounted on the spindle between the friction-stir welding tool and the bearings. This arrangement reduces and/or eliminates the need for more expensive and complex cooling means, such as a water cooled jacket having seals and a pump. Expected benefits include increased reliability and economy of operation.

Abstract: In a method for manufacturing a float valve apparatus including a valve case, an upper lid incorporated into this valve case to form a valve chamber, and a float valve liftably arranged inside the valve chamber, the upper lid being provided with a lead-out pipe connected to piping of the outside, an exhaust hole which communicates with this lead-out pipe and is opened in an inner surface of the upper lid, and a seal cap which is mounted so as to enclose this exhaust hole and forms a valve seat on which the float valve abuts, the seal cap is welded to an inner surface of the upper lid by spin welding.

Abstract: Provided are a method and a structure for joining members suited for reinforcement of a shape. An auxiliary member 7 is inserted into holes 9a and 9b of first and second portions 8a and 8b of the main member 6, respectively, such that the tip and base ends of the member 7 extend outwardly through the holes. The joining tool 5 is pushed, while being rotated, against the tip end of the auxiliary member 7, so that the material of the auxiliary member 7 softened due to frictional heat and plastic flow is deformed and pushed inside the main member 6 via the hole 9b. Then, the joining tool 5 is released from the main member 6 to allow into solidification the plastic flow portion of the auxiliary member 7. Further, the joining tool 5 is pushed, while being rotated, against the base end of the auxiliary member 7, so that the material of the auxiliary member 7 softened due to frictional heat and plastic flow is deformed and is pushed inside the main member 6 via the hole 9a.

Abstract: A method and a structure for joining members are provided which are suited for reinforcement of a shape. An auxiliary member 7 is inserted into respective holes 9a and 9b of first and second portions 8a and 8b of a main member 6 such that tip and base ends of the auxiliary member 7 are in the holes 9b and 9a of the second and first portions 8b and 8a, respectively. A joining tool 5 is pushed, while rotated, on the tip end of the auxiliary member 7 to soften the portion of the auxiliary member and the second portion 8b of the main member 6 due to frictional heat and plastic flow. Then, the joining tool 5 is released from the main member 6 to allow the second portion 8b and the plastic flow portion of the auxiliary member 7 to solidify. Further, the joining tool 5 is pushed, while rotated, on the base end of the auxiliary member 7 to soften the portion of the auxiliary member and the first portion 8a of the main member 6 due to frictional heat and plastic flow.

Abstract: A friction stir system for processing at least a first workpiece includes a spindle actuator coupled to a rotary tool comprising a rotating member for contacting and processing the first workpiece. A detection system is provided for obtaining information related to a lateral alignment of the rotating member. The detection system comprises at least one sensor for measuring a force experienced by the rotary tool or a parameter related to the force experienced by the rotary tool during processing, wherein the sensor provides sensor signals. A signal processing system is coupled to receive and analyze the sensor signals and determine a lateral alignment of the rotating member relative to a selected lateral position, a selected path, or a direction to decrease a lateral distance relative to the selected lateral position or selected path.

Abstract: Control systems, methods, and algorithms are provided for controlling the process parameters during FSW in order to repeatedly produce high quality welds for high temperature alloys such as titanium alloys and superalloys. In accordance with exemplary embodiments of the present invention, a desired range of forge load, pinch load, and/or travel load can be reliably maintained in a FSW system by adjusting the rotational speed thereof. In other embodiments, a desired temperature range of the tool or weld can be maintained by adjusting a plunge depth of pin tool for conventional FSW or distances between upper and lower shoulders for self-reacting FSW processes. Other embodiments of the present invention provide methods and/or apparatus suitable for rotational control and/or plunge depth control for FSW of titanium alloys and/or other high temperature alloys such as super alloys.

Abstract: The present invention discloses a multi-shouldered friction stir welding tool.

Abstract: One aspect of the present invention can include a friction welding method having a friction step for generating a friction heat by pressing the pair of works while relatively rotating the pair of works, and an upset step started before generating an approach margin at the pair of works at the friction step, restricting rotation of the pair of works relative to each other and applying an upset pressure between the pair of works.

Abstract: A friction stir welding apparatus capable of stably applying a pressure force without enlarging the apparatus, and a robot having thereof are provided. A rotating tool is provided with a rotational shaft and a hollow surrounding shaft is provided to surround the rotational shaft. The rotational shaft is movable along an axis-of-rotation and is rotated by a rotation drive motor about the axis-of-rotation. The surrounding shaft is rotatably supported by a main frame and an outer threaded portion is formed around the outer peripheral thereof to be threadedly engaged with a nut member. The rotating tool is rotatably supported by a header, and the header and the nut member are coupled together through a bracket. Therefore, when the surrounding shaft is rotated about the axis-of-rotation by the linear movement motor, the rotating tool is linearly moved through the nut member, the bracket and the header, and can apply a pressure force against work pieces.

Abstract: A friction welding apparatus includes a first holder for holding a first work piece, a second holder for holding a second work piece, a thrust mechanism and a shaft. The thrust mechanism moves the second holder toward or away from the first holder. The shaft is connected to the first holder and the second holder for receiving thrust caused by the thrust mechanism. The shaft has a tie rod and an externally threaded member which is coaxially connected to the tie rod so that the externally threaded member is rotatable on an axis thereof. The thrust mechanism has the externally threaded member, an internally threaded member and a thrust motor. The internally threaded member is provided in either one of the first holder and the second holder and engaged with the externally threaded member. The thrust motor rotates the externally threaded member relative to the internally threaded member.

Abstract: A friction stir spot welding tool having a rotatably driven shank. A shoulder adjacent to one end of the shank is generally circular in shape having a concave profile while a pin having a generally triangular cross-sectional shape protrudes axially outwardly from the shoulder. To perform the spot welding operation, the shank is rotatably driven and the shoulder is plunged into the workpiece such that the pin penetrates past the workpiece interface to a predetermined depth to perform the spot weld. The proposed triangular pin tool is found to significantly increase the weld strength when compared to conventional pin shaped tools due to the following: (1) it inhibits the formation of the vertical hook in the stir zone (the upward rise of the hook is arrested when the pin plunges into the workpieces interface), and (2) due to the asymmetric rotational pattern of the triangular pin it enhances the mixing of the material around the tool pin and oxide layer is dispersed (made discontinuous) in the stir zone.

Abstract: Friction stir weld tools configured to bond or laminate thin sheets. Friction stir weld tools have a first shoulder, a pin extending from a friction surface of the first shoulder, and a second shoulder. In some embodiments, the second shoulder is secured at least partially around the first shoulder and includes an engagement surface longitudinally recessed with respect to the friction surface of the first shoulder. In additional embodiments, the second shoulder is proximate the first shoulder and rotationally fixed. In yet additional embodiments, the pin has a diameter that is greater than the height of the pin and the second shoulder is secured at least partially around the first shoulder. Methods include manufacturing such friction stir weld tools. Methods include friction stir welding using such tools.

Abstract: A portable multi-axis load confirmation tool having a rotating ball on the end thereof follows a three-dimensional weld program path therewith. The ball reacts to an internal load cell for verifying weld program path dynamics before an actual program is run with friction stir welding tools. The load cell is connected to instrumentation electronics converting a load cell signal to a digital readout and comparing the load cell signal to weld program load requirements. The tool integrates into a tool holder loaded on a friction stir welding spindle for simulating an actual friction stir welding tool.

Abstract: A method including providing a first portion including one of an annular portion or a hub portion; rotating a second portion including the other of the hub portion or the annular portion; and pressing the second portion against the first portion such that friction between the hub portion and the annular portion causes a weld joint to be created; and wherein the annular portion may or may not include a frictional damping means, which may include an insert.

Abstract: Provided is an apparatus for welding upper and lower plates of a metal separating plate of a fuel cell which can simplify the welding of a separating plate, improve welding and watertight performance, and prevent the thermal deformation of a separating plate. The apparatus includes a supporting unit which is disposed below a main body and on which the metal separating plate is safely seated; a friction stir unit which faces the supporting unit, and welds the metal separating plate using a friction stir welding method; and a temperature control unit which is disposed either at the friction stir unit or at the supporting unit, measures a temperature of at least a portion of the metal separating plate during the welding, and controls an operation of the friction stir unit so that the temperature of the metal separating plate can be maintained within a predetermined range.

Abstract: A rotational friction welding apparatus and method for joining two components is disclosed. The apparatus includes a first spindle which turns and a second spindle which does not turn. A first component of the components that are to be connected together is mounted on the first, turning spindle, and a second component of the components that are to be connected together is mounted on the second, non-turning spindle, respectively, by way of a clamping device. Associated at least with the clamping device that is used to mount the first component on the first, turning spindle there is a planar toothing which for centering purposes and torque-transfer engages into a corresponding planar toothing associated with the first component.

Abstract: A method of friction stir welding and a non-consumable multi-section faced retractable shoulderless variable penetration friction stir welding tool. The tool includes a substantially cylindrical body portion, a head portion, and a tip section, each integral to the tool. The body portion has a longitudinal axis about which it is rotable, a diameter, a sidewall substantially parallel to the longitudinal axis, a proximal end, and a distal end. The head portion is located at the distal end of the body portion. The head portion includes a multi-section face, having a first face section and a second face section, that converges to the tip section. The tool is retractable, reduces overheating, improves weld quality by reducing internal voids and lack of fusion, and facilitates variable penetration welds.

Abstract: A friction stir welding tool having one or more tapered flats for promoting flow of weld material toward the pin terminus and one or more counter-spiraling channels or threads which for promoting flow of the weld material toward the tool shoulder.

Abstract: An apparatus and method for joining structural members to form preforms and structural assemblies are provided. The structural members are positioned so that joining surfaces thereof define an angled aperture, such a slot or frustoconical bore, that receives a corresponding joining member. The joining member is urged into the aperture against the joining surfaces and moved, for example, by oscillating or rotating the joining member, to friction weld the joining member to the structural members. Each structural member can include a clamping portion that is received by a clamping device that prevents the aperture from opening as the joining member is urged into the aperture. A gripping portion of the joining member and the clamping portions of the structural members can be trimmed from the resulting preform to form a finished structural assembly.

Abstract: Friction stir welding tool to facilitate stress reduction within the tool that may include a body, a pin, a tension member, and an end assembly, the tension member and end assembly facilitating axial compression of the pin. The tension member may be decoupled from the pin and/or body of the tool via one or more decoupling members. The end assembly may comprise spring members to provide an axial force to the tension member. The pin may include various features to facilitate stress reduction proximal the pin.

Abstract: A friction stir welding apparatus capable of stably applying a pressure force without enlarging the apparatus, and a robot having thereof are provided. A rotating tool is provided with a rotational shaft and a hollow surrounding shaft is provided to surround the rotational shaft. The rotational shaft is movable along an axis-of-rotation and is rotated by a rotation drive motor about the axis-of-rotation. The surrounding shaft is rotatably supported by a main frame and an outer threaded portion is formed around the outer peripheral thereof to be threadedly engaged with a nut member. The rotating tool is rotatably supported by a header, and the header and the nut member are coupled together through a bracket. Therefore, when the surrounding shaft is rotated about the axis-of-rotation by the linear movement motor, the rotating tool is linearly moved through the nut member, the bracket and the header, and can apply a pressure force against work pieces.

Abstract: A friction stir welding tool is used in welding structures. The tool comprises a shoulder and a probe extending from the shoulder. The probe has at least three sections equiangularly arranged around the longitudinal axis of the probe, each section comprising at least three contiguously arranged flats arranged about the axis of the probe. The flats are so arranged that the normal axes of the flats converge in a direction towards the axis of the probe thereby resulting in the sections each having a generally convex shape. The probe also includes a threaded portion disposed between each pair of adjacent generally convexly shaped unthreaded sections.

Abstract: The present invention provides an apparatus and improved method of friction stir spot welding that assures a predetermined bottom thickness and a reduction in variation in a series of resultant spot welds. The advantage of the present invention lies in that the plunge distance is controlled from the top plane of the anvil against which the bottom thickness is specified, and systematically adjusted to account for changing system parameters, such as, but not limited to, deflection and thermal expansion of the weld gun. The present invention also provides for improved and controlled weld quality through implementation of a dwell operation or dwell operations, whereby weld heat input is manipulated by causing the weld tool to dwell in a dwell region or at a desired depth or depths within the workpiece(s) for a predetermined time interval to achieve desired mechanical properties of the resultant weld joint.

Abstract: A friction stir welder includes a clamp mounted about the head from which the welding pin protrudes, with the head being extendable into and retractable from the clamp to insert and remove the welding pin from the area between the clamp halves (wherein a workpiece to be welded may be fit). The interiors of the clamp halves include rollers for engaging the workpiece, with at least one of the rollers being driven to feed the workpiece between the clamp halves and thereby move the workpiece with respect to the welding pin. Thus, the clamp halves may be closed about a workpiece, the welding pin can be driven into the clamped workpiece, and the workpiece can then be fed through the clamp halves to move the welding pin about the workpiece.

Abstract: A recess portion with a substantially circular cross-section is provided in the upper end surface of a supporting jig. When a probe of a device for friction stir welding is buried in the upper end surface of a layered portion, material in the vicinity of the buried portion flows plastically. This causes the plastically flowed material to flow into the recess portion, and as a result, the material is stirred in a relatively large region. When the material that flowed into the recess portion is cooled and solidified, a friction stir-welded portion-possessing member having a projection portion is obtained.

Abstract: A friction stir welding tool is described and which includes a shank portion; a shoulder portion which is releasably engageable with the shank portion; and a pin which is releasably engageable with the shoulder portion.

Abstract: The invention relates to a friction stir welding head having a housing and a welding tool with a rotating welding pin and a rotating shoulder tool for welding workpieces which rest on a workpiece rest, with the shoulder tool, which rotates in synchronism with the welding pin, coaxially surrounding the welding pin. According to the invention, a first distance between a first laser rangefinder and a welding pin section 4a can be determined by means of the first laser rangefinder. This makes it possible to determine at least one change in the distance between the welding pin tip and the workpiece rest by means of a first laser rangefinder.

Abstract: An apparatus and method for joining structural members to form preforms and structural assemblies are provided. The structural members are positioned so that joining surfaces thereof define an angled aperture, such a slot or frustoconical bore, that receives a corresponding joining member. The joining member is urged into the aperture against the joining surfaces and moved, for example, by oscillating or rotating the joining member, to friction weld the joining member to the structural members. Each structural member can include a clamping portion that is received by a clamping device that prevents the aperture from opening as the joining member is urged into the aperture. A gripping portion of the joining member and the clamping portions of the structural members can be trimmed from the resulting preform to form a finished structural assembly.

Abstract: There is provided a mandrel for spin forming that has a backing plate with removably attached mandrel portions and mandrel spacers, such that the mandrel is adaptable to numerous configurations. The various configurations of the mandrel are used to provide different spin forming contour surfaces upon which metal sheets or other spin formable materials can be spin formed. The adaptable mandrel also provides the ability to create a desired spin formed product from either a single metal sheet or multiple metal sheets joined by friction stir welding or other suitable processes. A spin formed welded metal sheet may also undergo a trimming process to remove the portions of the welded metal sheet having sufficiently different material properties resulting from the weld process, including the weld joint.

Abstract: A machining device comprising five axial kinetic coordinate systems that can be controlled simultaneously, three axes of which, are linear moving axes and two axes of which are rotary axes, with one axis of the five axes being provided with a tool rotating function, whereby said machining device is equipped with a cutting tool 51 and a friction stir welding tool 52. The current value observed when a large-diameter portion of said tool 52 contacts the work object is set in advance, and by observing the torque current of the rotary shaft of the tool 52 during friction stir welding, the insertion depth of the tool 52 can be controlled by maintaining the observed torque current above the preset current value, thus providing a good weld. A single device can provide both the cutting and the welding. Thus, it is possible to reduce equipment cost, installation space, plant area, lead time and production cost.

Abstract: An apparatus is disclosed for performing high speed welding of two or more materials. The apparatus includes an outer vessel having an inner surface and a central axis. At least one inner vessel is positioned within the outer vessel and adapted to receive at least two materials to be subjected to a bonding or welding process. A drive system causes the inner vessel to rotate with respect to the outer vessel. The apparatus is designed to inhibit the formation of an oxidation layer on the materials during rotation. In one embodiment, the oxidation layer is inhibited by creating a vacuum within the inner vessel. In another embodiment, the inner vessel is filled with a gas which inhibits formation of an oxide layer on the materials. A method for high speed welding is also disclosed.

Abstract: A probe for friction stir welding MMCs, ferrous alloys, non-ferrous alloys, and superalloys, as well as non-ferrous alloys, the probe including a shank, a shoulder, and a pin disposed through the shoulder and into the shank, wherein the pin and the shoulder at least include a coating comprised of a superabrasive material, the pin and shoulder being designed to reduce stress risers, disposing a collar around a portion of the shoulder and the shank to thereby prevent movement of the shoulder relative to the shank, and incorporating thermal management by providing a thermal flow barrier between the shoulder and the shank, and between the collar and the tool.

Abstract: A spindle for use in an automobile chassis is provided. An aluminum knuckle with an axial through hole defined in its interior is provided along with a substantially cylindrical steel stem with an interlocking feature defined on one end. The interlocking feature has an extended flange with an outer diameter greater than the inner diameter of the through hole in the knuckle. The interlocking feature also has a frusto-conical section and at least a portion of the stem is welded to at least a portion of the through hole such that the interlocking feature is within the through hole.

Abstract: A friction stir rivet is rotated and driven through a first fusible workpiece into an engaged second fusible workpiece, causing local portions of the first and second workpieces to plasticize. A slideable cap contacts the exposed surface of the first workpiece shortly after the process begins. The contact causes the cap to act as a retaining element, limiting the escape of plasticized material from stir site. Once the rivet is driven into the first and second workpieces, rotation ceases and the plasticized material hardens around the rivet. A weld is thus created, joining the workpieces and encompassing the rivet, which provides additional mechanical strength.

Abstract: The present invention relates to rotary friction welding and non-rotary motion friction welding, providing means for controlling ductilities of the components during the welding process so as to bias the welding process in favor of a first component or to match the ductilities of different components thereby facilitating the welding process.

Abstract: A portable inertia welder is mounted in a housing so as to afford both axial and rotational movement of a shaft with flywheel weights. Rotational motion is provided by a motor affixed to the drive shaft while axial motion is provided by means of a hydraulic housing mounted around said shaft. A chuck mounted to the shaft holds a first workpiece for rotational and axial displacement. Holding devices such as vacuum cups secure the welder to a second workpiece. A flash cutting tool and an appurtenance with a flash trap, welding flats, and an internally threaded bore are described.

Abstract: A rod material made of Ti alloy has a larger diameter portion at the end, which is joined with the end of material made of Ti—Al intermetallic compound, by friction welding, to form a poppet valve for an internal combustion engine. Instead of providing such larger diameter portion, the end of the material made of Ti—Al intermetallic compound may be heated to facilitate joining.

Abstract: A friction stir welding tool is provided for joining together workpieces utilizing friction stir welding processes. The inventive tool includes a support body rotatable about a first axis and having a distal end defining a shoulder. A rotatable pin extends from the distal end of the support body downward and away from the shoulder. The shoulder of the support body includes at least one section that is tapered, with the taper extending downward toward the pin.