Abstract: A tool assembly for shaping workpieces, which comprises a reciprocable punch having a working end engageable with a die to shape a workpiece therebetween. The punch is mounted at its driven end on a reciprocable punch actuator and extends through a floating punch guide having an end adjacent the die which is axially and circumferentially engaged with a recess in the die to align the die and punch axes during the workpiece shaping operation. A workpiece feed tube opens laterally into the punch guide, and the punch guide is reciprocable in response to reciprocation of the punch to open and close the discharge end of the feed tube so as to assure singular feeding of workpieces to the die cavity.

Abstract: In accordance with the present invention, there is provided a method for increasing the longitudinally compressive and tensile proportionality limits and ultimate strengths of an elongated structural member by applying to the member a longitudinally compressive load. To increase the proportionality limits of the member, a longitudinally compressive load is applied to the member which is close to its maximum load. In order to prevent buckling of the member under such a load, the member is confined in an encasement which allows the member to yield longitudinally without bending. By applying to the member a longitudinally compressive load much greater than the member's original (i.e., untreated) ultimate compressive strength, both the ultimate strengths and the proportionality limits of the member are increased.

Abstract: A method and an apparatus for reconditioning worn electrodes for resistance welding. The worn electrodes are pressed into a die by a punch and thus restored to their original shape or given a different shape.

Abstract: An aluminum header tube having a plurality of integral and regularly spaced lateral extensions is formed according to a method which includes the steps of forming stubs for the extensions, inserting a tool through each stub and into the interior of the header tube, sizing each stub to reduce its inside and outside diameter and, while maintaining the clamp, withdrawing the tool through the stub to cause metal to flow outwardly, thus raising or lengthening the stub to the desired degree.

Abstract: A separable die block contains a cavity for shaping a part from a slug of cylindrical malleable metal and a cylindrical injector for injecting the slug of metal into the die block cavity, the injector having an outer sleeve and a coaxial inner pin which are axially moveable with respect to one another for forming an opening or a recess in the part. As a further feature, a moveable plunger in the die block is in communication with the die block cavity for further altering the shape of the formed part, if desired.

Abstract: A bearing is manufactured by applying an axial pressing force to a cylindrical wound bush and thereby forming a notch-free flange at one end of the bush which is tapered previously. The flange is formed through a kind of plastic flow induced in the tapered end by the force.

Abstract: Improved electrolytic cell performance is obtained by modifying a standard box anode by increasing the width thereof by permanently deforming the anode mesh within the immediate vicinity of the anode post. Increases in anode width of from about 3 mm to about 12 mm, resulting in reduction of interelectrode gap of about 1.5 mm to about 6 mm, have been found advantageous. Improvement is enhanced by the use of a polymer bonded asbestos diaphragm.

Abstract: A tool for use in manufacture of a hollow article with an undercut internal surface, such as the outer member of a constant velocity ratio universal joint, comprising first and second elements (34,38) together defining the shape required in the article interior and an internal cavity (40). An expander (23) fits in the cavity to hold the elements in their operative positions, and the first elements have parallel or outwardly convergent sides which enable their inward movement between the second elements after withdrawal of the expander from the cavity. After such inward movement, the first elements can be withdrawn from the shaped article, followed by the second elements.

Abstract: A pill-shaped billet which is tapered in thickness toward an outer, relatively thin rim, extending circumferentially therearound, is cold formed into a metal part having an annular flange. Upper and lower die elements define cavities, and shoulders extending circumferentially therearound, and are positioned in a sleeve with the shoulders being directly opposed, thereby defining an annular space. The billet is placed between the upper and lower die elements in the sleeve with the rim of the billet in the annular space. The upper and lower die elements contact the billet only along the edges between their respective shoulders and cavities. When the upper and lower die elements are moved toward each other, the annular flange is formed by extruding radially outward the part of the billet between the shoulders, while simultaneously cold forming the billet into the first and second cavities.

Abstract: A tool for stamping annular blanks to form retainers for truncated spherical members in a single stroke stamping operation comprises a sectored punch having at least one pair of diametrically opposed sectors of a cylinder separated from one another at their apexes such that the sectors of two punches can be intermated. The distal ends of the sectors are spherically contoured such that alternating spherical surfaces are formed on the inside surface of the retainers by two intermating sectored punches. The sectored punches form alternating cylindrical and spherical surfaces into the upper and lower portions of a blank to form the retainer. The cylindrical surfaces permit spherical members to be inserted into the retainers by hand or with the use of hand tools.

Abstract: A bevel gear is made by means of a die, a punch, and two concentrical counterpunches, one having a particularly contoured extension. A cylindrical blank, having a diameter not larger than the smallest bevel gear root circle, is inserted in the die; a portion is held by one counterpunch but reverse-extruded in part into the gap between that counterpunch and the advancing punch. A portion of the blank inserted into the interior of the die flows concurrently radially into the small-diameter portion of the die cavity. Subsequently, the reverse-extruded, tubular portion is forced back in parts by the second counterpunch, acting in the gap, to fill the large-diameter portion of the cavity. A tubular shaft extension may remain on the gear.

Abstract: A method and apparatus for producing a stepped hollow component such as, for example, a gear blank. A solid slug, provided with a disc portion and a projecting portion, is placed in a rigid cylindrical recess formed between a counterpunch and a hollow mold. An annular upper surface of the disc portion and a side surface of the projecting portion are precompressed by an outer punch so as to restrain an outer periphery of the solid slug. A closed-base hole is formed in a center of the solid slug by a plastic deformation caused by an inner punch. The plastic deformation by the inner punch causes material of the solid slug to flow biaxially in the radial and axial direction of the solid slug.

Abstract: A nut forming apparatus in which a pair of identical die assemblies are housed in a pair of diametrically opposed boxes in a rotary block and rearward movement of the die assembly relative to the rotary block at a first die station is precluded but rearward movement of that die assembly is allowed as it is moved to a second die station by rotary movement of the rotary block. A fixed back pierce pin, associated with each die assembly, is thus inoperative in response to a front forming blow struck by a punch positioned at the first die station but operates to back pierce the nut blank upon rearward movement of the die assembly in response to a front forming blow struck by a punch positioned at the second die station. A pair of cammingly interfaced cylindrical members associated with each die undergo relative rotation as the die assembly is moved by rotation of the rotary block between the first and second die stations to respectively preclude and allow rearward movement at that die assembly.

Abstract: A forging method for producing a flanged shaft such as, for example, a crankshaft, provided at its intermediate portion with a flange with the flanged shaft being formed from a blank having a diameter which is smaller than the diameter of the shaft end portions but large enough to prevent buckling of the blank when the latter is compressed in the axial direction. The blank is placed within a closed die apparatus and is axially compressed by a punch so that it is possible to produce the flanged shaft at a high dimensional precision and at a high yield, while reducing the time and labor for finishing work conducted after the forging, without requiring any large-size press.

Abstract: A tool, and method, for making the outer member of a constant velocity universal joint of the cross-groove type, the outer member being of hollow form having in its interior two sets of helical grooves of opposite hand. The tool comprises first and second parts 15, 21 mounted for axial movement relative to one another, the parts having portions 23, 17 which can be brought into and out of mutual intercalation by such axial movement, the portions 17 carrying projections 18 which form the grooves of one hand and the portions 23 carrying projections 24 which form the grooves of the other hand.

Abstract: A preheated billet (A) is disposed in a billet receiving region (20) of a lower die (B). The lower preforming die defines a throat region (30) which is smaller in transverse cross section than the billet receiving region and disposed immediately therebelow. The lower die further defines an enlarged relief region (40) which is larger in all transverse dimensions than the throat region and disposed immediately therebelow. An upper die (C) includes a billet engaging surface (50) which has substantially the same transverse cross section as the billet receiving region. The upper die is forced downward by a hydraulic press or the like into engagement with the billet. As the upper preforming die continues downward, the billet engaging surface is telescopically received within the billet receiving region pushing and deforming the billet ahead of it.

Abstract: Blanks of noncircular, especially polygonal (e.g. heptagonal), outline are fed to a die-stamping press of an embossing plant such as a mint by means of a turntable with radially oriented transport plates projecting beyond its periphery at angularly equispaced locations. Each transport plate has an outwardly open recess with inner edges conforming to part of the blank outline and with two substantially parallel jaws spaced apart by the maximum width of the blanks, the depth of the recess being less than this maximum width to let an inserted blank protrude by one corner in an incorrect position and by two corners but to a lesser extent in a correct position.

Abstract: A blank section of a steel rod is heated and then successively impacted between hot forging dies to form a preform or rough forging ball joint socket having a tubular socket portion and a laterally projecting mounting flange portion. The rough forging is then inserted into a die set assembly including an upper die member surrounding a relatively movable punch and a lower die member surrounding a relatively movable ejector member. The upper die member is supported by a piston of a hydraulic cylinder which moves with the punch, and the upper and lower die members cooperate to produce the desired precision external configuration of the socket and flange portions. After the die members are closed, the punch cooperates with the ejector member to form the desired precision internal configuration of the tubular socket portion.

Abstract: A die package for forging a central disc structure having a plurality of integrally formed appendages extending radially outwardly therefrom includes a circumferential array of abutting die segments defining a central cavity within the array and appendage forming cavities between the segments. Each die segment has a locating hole in its upper surface, and an annular support member overlies the holes and has a plurality of locating holes therein, one hole corresponding to each hole in said die segments. A non-metallic rod, such as a glass rod, is disposed tightly within and extends between each pair of aligned holes, thereby locating the die segments accurately relative to each other and to a central axis of the die package. The rods are shearable at elevated temperatures to enable radial movement of the die segments after forging for releasing the forged component from the die package.

Abstract: To produce an annular metal frame having an L shaped half-section for a lipped seal, a metal strip is cut into lengths, each of these lengths is rolled up circularly until its two ends are in abutment, so as to form a cylindrical ring (7), then this ring is driven into the cavity of small thickness defined between two parallel guide surfaces (S, S'), the entrance to said cavity having a shape complementary to that of the ring and the bottom of the cavity having a shape complementary to that of the frame to be produced.

Abstract: An apparatus (100) and process for multistep heading of elongated stock to form a brush contact (10) with a relatively great reduction in the length of the wire stock material (386) achieved during successive heading steps, including a rotary holder plate (112) mounting a series of blank clamping holders (166) indexed through a series of stations and a series of coning dies (240) and punches (244) carried by independently actuated tooling plates (114, 116) which are axially advanced during forming of the blanks. A final forming step involves a reverse extrusion to create an endwise axial opening (26). The apparatus (100) also includes a feed mechanism (148) and a cutoff mechanism (160) for forming blanks from wire stock (386). A clamping member (178) is associated with each holder (166) for clamping the blank for securement during the forming steps, which is unlocked at an ejection station to enable removal of the formed article by an ejection mechanism (610).

Abstract: A method is provided of making a collar (10') having an annular flat outer surface (118) and an inner surface having an inwardly tapering first portion (120) and peripheral outwardly tapering notch portion (122). The method includes the steps of providing a die assembly including a die cavity having an annular seating surface (130) with an opening (132) therethrough and an annular side wall (134) and a reciprocating forming die (136). The die (136) includes a shoulder portion (138) closely fitting against the side wall (134) of the cavity (128) and a cylindrical portion (140) and a frustoconical portion (142) therebetween. The forming die (136) enters the die cavity (128) whereby the cylindrical portion (140) enters the opening (132) of the seating surface (130) so that the cylindrical portion is spaced therefrom.

Abstract: A method of producing a metal sleeve having at least one recess open at the nd face extending over a portion of the axial length of the sleeve from a cylindrical pipe section comprising (a) inserting a cylindrical pipe section into the annular cavity of a die which cavity is radially greater than the wall thickness of the pipe section, (b) subjecting the pipe section to axial ram pressure whereby a bulge in the central portion of the pipe section occurs with the central portion bearing against the outer limiting wall of the die cavity and the end portions bearing against the inner limiting wall of the die cavity, (c) applying further pressure on the pipe section whereby it fills the die cavity except for a circular depression in the center of the pipe section bore and (d) acting on the resulting pipe section with a second ram with an end face with contours corresponding to the recesses whereby the displaced material from the contours enter into the circular depression of the pipe section to partially fill the

Abstract: A method of producing a plurality of identical ring-shaped metal parts from a single blank in the form of solid rod without forming any hole in the blank and without cross-sectionally cutting the blank. The outer periphery of the blank corresponds to the inner periphery of the metal parts to be produced. First the blank is longitudinally compressed such that an end portion of the blank undergoes upsetting and provides a laterally expanded portion having a side periphery corresponding to the outer periphery of the metal parts and a length corresonding to the thickness of the metal parts. Then the laterally expanded portion is subjected to shearing along a plane defining the outer periphery of the blank to part its peripheral region as one of the ring-shaped metal parts. The blank remains in the solid rod form, though somewhat shortened, and therefore can be used to produce additional metal parts by repeating the same procedure until it becomes very short.

Abstract: Method and apparatus for making certain types of parts which are stepped in one plane and curved in other planes transverse to the planes in which they are stepped. The invention uses a specially shaped billet which is formed into the part in a closed flashless die set at warm forging temperatures.

Abstract: A die for forging a part with internal, tapered grooves, for instance, such as a socket with a plurality of inner races used for a joint. The blank is formed into a given shape by a cylindrical projection provided in the upper die so as to compress the outer peripheral surface thereof, in cooperation with the liner-grooving dies, when the upper die is lowered. After the forging step, the locking pin inserted in the lower die is lowered so as to move the liner-grooving die toward the stamping axis so that the forged workpiece can be removed from the lower die easily and next ejected by the ejector pin.

Abstract: A blank material having a configuration corresponding to the flange part of the article is first punched by a punch member and a die member from a planar strip material, the blank is press-formed into a hollow article by further pressing the punch member and die member and projecting a mandrel having outer diameter corresponding to the inner diameter of the hollow article. Then, the punch member, die member and mandrel are returned to their original position thereby to deliver a completed article. The above one cycle operation is continuously repeated per shift of the strip member by one article distance.

Abstract: A method for cold forming a metallic billet into an article having divergent members with a single hit comprises depositing the billet centrally within a die cavity between a first member and a second member. The first and second members are hydraulically urged toward one another at an equivalent velocity until the divergent portions of the die cavity are filled. The forming velocity is between about 30 percent and about 60 percent of the normal forming velocity for the material comprising the billet.

Abstract: Apparatus for the manufacture of a rim for the wheel of a commercial load carrying or passenger service vehicle, which apparatus comprises in combination bending apparatus for bending steel strip and butt welding the edges thereof to form a cylindrical component and a plurality of press tools for converting the component into a rim wherein at least one of the press tools comprises an annular die having located within the opening thereof pressure plate adapted to ascend or descend within such opening and on which a cylindrical component to be formed into the rim is adapted to be located above the bottom of the annular die, and pressure elements mounted above the die and adapted to engage therewith through its opening in such a way as to subject the component to compressive load against the inner surface of the die whereby the contour of the die or of the die and the pressure elements is imparted to the component, wherein the pressure elements comprises a combination of upper and lower punch tools resiliently i

Abstract: Cylindrical blanks are formed into wheels, each with an integral shaft; and one of the shafts is shrunk into the other one in order to complete the set. Each wheel may have an integral, outwardly extending bearing hub.

Abstract: A segmented female die for use in a closed die set comprising a pair of similar center segments and a pair of similar "half moon" shaped outside segments. The four segments also define the ejector pin opening. The die segments are prevented from relative motion between themselves by interlocks comprising closely mating protrusions and guideways which, in cooperation with other means, produce a rigid female die. The interlocks permit the use of relatively simple manufacturing techniques such as grinding as opposed to more sophisticated techniques such as electrical discharge machining.

Abstract: The apparatus includes a die, a punch, and a concentric counterpunch having an annular front extension; the die cavity has a spline-shaft-like extension and the counterpunch extension has a frustroconical tip and/or lateral teeth which mesh with the spline shaft. The counterpunch is spring-mounted upon the punch carrier.

Abstract: A method and apparatus for forging large irregular shapes in a closed-die operation, particularly for forging a blank to be machined to form a fluid end piece of a pump. The blank has a substantially rectangular parallelepiped body and a block projecting sideways from the body. The apparatus has a die opening of a shape to form the blank. In a single operation in a conventional open-die press a heated workpiece is upset and a portion squeezed sideways to form the block.

Abstract: A method and die assembly for forging a rolling mill coupling, the body of which has a socket in one end and tangs extending from the other end. The assembly comprises bottom and top punches which extrude metal downwardly from the bottom portion of a workpiece and upwardly from the top portion to form walls defining the socket at one end of the workpiece and tangs extending from the other end.

Abstract: A method of producing trimming dies with a conical many-sided bore for use in a screw trimming press. A trimming die blank is produced with an outer diameter corresponding to the inner diameter of a cup-shaped holder and to a finished height and with a cylindrical inner bore. The many-sided bore is produced by cold deformation of the inner diameter by means of a many-sided punch introduced to a limited extent into the inner bore while preserving the outer diameter. Apparatus for carrying out the method includes a holder for the trimming die blank. A spacer ring located below the blank and resting on the base of the holder in use, a guide sleeve and a many-sided punch guidable by said guide sleeve and having a length exceeding that of the guide sleeve by an amount corresponding to a predetermined insertion depth of the punch in the blank. The base of the holder has an ejector bush with an ejector mandrel.

Abstract: A blank suitable for minting to form a coin or similarly disc-shaped article has an appropriately disc-shaped steel core completely encased by a copper coating electroplated thereof. The blank is produced by electroplating a copper coating onto an appropriately disc-shaped steel core such that the copper coating completely encases the steel core.

Abstract: A planar material to be press-formed is confined in a space having a contour corresponding to the outer contour of the flange part of an article to be produced and is pressed between a punch member having a through hole corresponding to the outer contour of the hollow main part of the article and another die member holding slidably a mandrel having an outer contour corresponding to the inner contour of the internal bore of the hollow article, the mandrel being simultaneously projected into the through hole of the first member. By the pressing action, the peripheral part of the material is formed into the flange part of the article while an inward flow of the material is caused, thereby elevating the surface of the material in the through hole of the punch member and forming a recess in the opposite side surface of the material. The mandrel is projected simultaneously with said pressing action, whereby topless hat-shaped product is easily formed by one step.

Abstract: A method and apparatus are provided for producing a cross-slotted die for forming cross-slotted screw heads. One end face of a cylindrical blank is turned to form a cone having a cone angle of between 124.degree. and 140.degree.. The cross shape is produced in this face by a single cold forming stage while preserving the outer diameter of the blank. The blank is held in a cylindrical holder having a bore with an internal diameter corresponding to the diameter of the cylindrical blank. An ejection mandrel engages in the bore to form the base of the holder. A platen carries a punch for insertion into the bore to deform the end face of the blank.

Abstract: A method and apparatus for upsetting a tube end using a one-piece upset die. The tube is heated at the end to be upset and secured in a gripper clamp so as to remain stationary during the upset operation. The upset die is hydrualically forced over the tube end and a mandrel is hydraulically positioned into the tube end. A longitudinal compressive force is then hydraulically applied to upset the tube end. The upset die is hydraulically pulled off the upset tube and thereby accomplishing removal of the tube from the one-piece die without damage to the tube or the die.

Abstract: Apparatus and a method disclosed for forming an axle spindle from a hollow axle blank incorporate a hollow punch having a metallic body with an inner work surface defining a work opening and a mandrel fixed within the work opening projecting toward an open end thereof from a closed end of the opening. During forming, the punch is moved relative to the axle blank in the direction the mandrel projects so that the mandrel is received within the hollow axle blank as the work surface of the punch body forms the blank about the mandrel to provide a spindle. Preferably, several punches of this type are utilized to complete the spindle forming process on the axle blank. Each punch preferably has an elongated annular shape with a round inner work surface and a round outer surface on the mandrel so that the formed spindle is of a round shape. One of the punches which causes outward material movement has an undercut on its mandrel to facilitate punch withdrawal.

Abstract: A process and associated apparatus are provided for producing cold flow formed items from slugs. First and second dies are aligned for relative movement axially towards and away from one another. The dies have respective opposed first and second faces and the first face defines a cavity having portions including generally axial walls. The first die has a peripheral chamfer extending axially away from the first face and a sleeve is provided containing the dies to combine with outer parts of the second face and the peripheral chamfer to define an annular space. The slug is formed into the item by causing relative movement between the dies to impact the slug and then causing further relative movement so that the slug is caused to flow into contact with the axial walls and also into the annular space so that destructive forces applied to the axial walls are countered by forces applied to the chamfer thereby stabilizing the material of the first die between the axial walls and the chamfer.

Abstract: A punch and die assembly for use in the production of heat exchanger fins comprising: a fixed lower tool holder including an ironing punch having the same dimension as a predetermined flanged aperture, and a movable upper tool holder having a die matching said ironing punch, wherein said punch is allowed to displace horizontally and can always be held concentrically to the die without requiring any particular adjustment and whereby uniform products can be continuously obtained.

Abstract: The invention relates to the cold extrusion of a part having a polygonal interior and a cylindrical exterior. Instead of the usual process of forcing a polygonal punch into a billet in a single extrusion step, the new method employs a plurality of extrusion steps, first forming a lobed preparatory blank and then in a second extrusion step providing a punch and die combination whereby the external lobes of the intermediate part are forced radially inwardly. In the second extrusion step a polygonal punch is used to provide the proper polygonal interior surface. A cooperating die is provided with an upper lobed cavity for receiving the lobed preparatory blank and this die is oriented with respect to the polygonal punch so that the interior lobes of the die are exactly opposite the flats of the polygonal punch.

Abstract: A method of making a dripless tubular metal can nozzle forms a hem at the rim of the nozzle by doubling-over the metal at the top end of the tube so the terminal edge of the tube lies on top of the hem and radially inwardly from the outward extremity of the rim. The sharp bend formed by doubling-over the metal to make the hem is the outward extremity of the rim, and is effective to prevent formation of drips.

Abstract: An improved method is disclosed for making spur gears having teeth with axially crowned working faces. A sintered powdered metal compact is formed in the shape of the desired gear, but slightly oversized and preferably with gear teeth having working faces that are uncrowned in the direction parallel to axis of rotation of the gear. The compact is forced into a smooth circular die cavity having a diameter slightly less than the outer diameter of the compact. Only the tips of the gear teeth engage the die wall. While the compact is constrained within the die, axial compressing forces are applied to it and gear teeth having axially crowned working faces are produced. At the same time, the gear is finish sized to desired dimensions.

Abstract: Apparatus and a method disclosed for forming an axle spindle from a hollow axle blank incorporate a hollow punch having a metallic body with an inner work surface defining a work opening and a mandrel fixed within the work opening projecting toward an open end thereof from a closed end of the opening. During forming, the punch is moved relative to the axle blank in the direction of the mandrel projects so that the mandrel is received within the hollow axle blank as the work surface of the punch body forms the blank about the mandrel to provide a spindle. Preferably, several punches of this type are utilized to complete the spindle forming process on the axle blank. Each punch preferably has an elongated annular shape with a round inner work surface and a round outer surface on the mandrel so that the formed spindle is of a round shape. One of the punches which causes outward material movement has an undercut on its mandrel to facilitate punch withdrawal.

Abstract: An axle making method and apparatus for forming a unitary tubular axle blank with an I-beam section along an intermediate axle portion and with a bifurcated axle end for supporting a wheel spindle by ball joints. Inward deformations are formed in side walls of the intermediate axle portion to form the I-beam section by apparatus including a pair of punches with opposed forming projections between which the blank is received. Apparatus for forming the bifurcated axle end incorporates cooperable female dies and male punches with complementary work surfaces for forming the projections from a notched axle blank end and with edge work surfaces on the punch for axially upsetting webbed side walls extending between the projections in order to maintain the wall thickness of the webbed side walls at least as great as the wall thickness of the intermediate axle portion.

Abstract: A method of, and apparatus for, fabricating a substantially U-shaped body, especially a fork-type joint of a Cardan or universal joint from a blank which is worked by cold press forming while using dies and punches. During a first step there is extruded from a substantially parallelepiped-shaped blank two leg members with the aid of a first die and a first punch, and during a second step the pressed-out or extruded legs are brought into a final shape with the aid of a second die and a second punch.

Abstract: When a metal piece is forced to undergo a 180.degree. bend with a press, in order that the outer end face of the bent portion be square rather than rounded, the portion to be bent is put in a die and buckled toward the folding line while bending is effected. Also a number of T-shaped projections radially extending from the outer periphery of an annular iron plate are formed with the lug portions of such projections bent so that the outer ends of the bent portions are formed flat.

Abstract: A method of manufacturing an extruded steel component for use in a roller clutch assembly comprises initially providing a steel preform which defines a hollow shank part of the required component and which includes a hollow head portion tapering inwardly to the shank part, the external diameter of the head portion being substantially equal to the external diameter of a hollow head part of the required component, but the bore in the head portion having a diameter less than that required for the head part. Then with the preform positioned in a die cavity of the shape of the required component, an extrusion operation is performed on the head portion of the preform using a punch including inner and outer, relatively movable punch members, the inner punch member defining the shape of the bore required in the head part of the component.