Dart flight stem

Abstract

A dart flight stem 100 comprises a first portion 140 and a second portion. The first portion 140 is formed from a first material and the second portion is formed from a second material different to the first material. The second portion is moulded or 3D-printed. Additionally, there is disclosed a dart flight stem comprising a specular component arranged to reflect light arriving from a predominantly radial direction with respect to a longitudinal axis of the flight stem towards a back end of the flight stem.

Description

Technical Field The present invention relates to darts, specifically those used in the popular game that involves throwing darts at a target dart board, and more particularly to flight stems for darts and methods of manufacturing these. Background The game of darts is well known and has existed in one form or another for centuries. It is a highly popular international sport and is televised around the World. The modern version of darts is played by two players taking turns to throw three darts in sequence into a dart board. The front face of the dart board describes a circular scoring zone that is divided into twenty numbered segments around a central bullseye. Points are awarded to each player corresponding to the number of the segment into which each of their thrown darts sticks. Each segment is sub-divided into bands, with a central band awarding triple points and an outermost band awarding double points. Adjacent segments of the board are painted in alternating colours, typically black and white. The adjacent segments and bands are also physically separated from one another by a frame of wire that runs along each boundary therebetween on the front face of the dart board. Each dart is constructed with a point (or tip), a barrel, a stem (or shaft), and a flight. The point is arranged to project forward from the barrel at the front of the dart and is designed to impact and stick into the dart board. The barrel is a substantially cylindrical body typically extending about half to two-thirds of the length of the dart. The stem extends backwards from the barrel and carries the flight at the back of the dart, which serves to stabilise the dart in flight when thrown. Typically, the stem is made of lighter-weight material than the barrel and is threaded at its front end so that it can be screwed into the back end of the barrel to assemble the dart. The threaded connection allows the stem to be unscrewed and detached from the barrel, for example to disassemble the dart for storage in a case or for replacement in the event of the stem breaking. In order to score highly and efficiently, darts players typically attempt to group their three darts as closely as possible on the dart board. If the first dart is well placed, it can act as a guide for subsequent darts, with the flight, stem and barrel of the first dart helping to guide the tip of the next incoming dart into position adjacent the tip of the first dart. Whether played professionally or on an amateur level, darts is most often played in a darkened room, for example with spotlights directed onto the dart board to illuminate it but that can cast shadows over the scoring area, or in otherwise adverse lighting conditions. This can make it difficult for a player to see the position and orientation of a dart sticking out of the dart board, and consequently can impact the player's ability to aim and throw subsequent darts. To improve visibility for the darts players and eliminate or reduce shadows, it has become common to install a light ring around the dart board that will illuminate the board with substantially equal intensity from all sides. However, the small cross-sectional size of a dart and its flight can mean it is still difficult for players (and television viewers alike) to see clearly where each dart has impacted and sticks out from the board. The point and barrel of a dart are made of resilient materials. The barrel is typically made from a tungsten alloy to provide the dart with a front-loaded mass distribution with minimum barrel diameter, so as to promote stable flight and permit close grouping of thrown darts. By contrast, the stem is normally made of a lighter-weight polymer material such as nylon or polycarbonate. While the front end of the stem is provided with a thread for connection to the barrel, the back end of the stem is formed with four elongate petals defining a cross-slit between them (when viewed from the rear of the stem) for receiving the flight in the slits and thereby gripping the flight between the petals. The threaded connection and the bases of the petals, in particular, represent areas of stress concentration where the stem nay break through repeated use or due to the darts landing on the stem if the dart bounces off or out of the dart board. Nylon provides a resilient material that is more likely to deform than to break and that may survive being bent back into shape if it becomes deformed, whereas polycarbonate is relatively brittle and prone to fracture at the stress concentration sites. Conversely, polycarbonate can be moulded as a transparent clear or coloured stem that many players consider to be more attractive or to have enhanced visibility when the dart is sticking out of the dart board, whereas nylon stems tend to be opaque. Summary of the Present Invention The present invention has been made in view of the realisation and recognition by the inventors of the aforementioned problems which may arise in prior art designs. The present invention seeks to alleviate or solve one or more of these problems. 29 01 24 According to a first aspect of the present invention, there is provided a dart flight sten comprising a first portion and a second portion, wherein the first portion is formed from a first material and the second portion is moulded or 3D- 5 printed from a second material different from the first material. According to a second aspect of the present invention, there is provided a method of manufacturing a dart flight stem 10 comprising: providing a first portion of the flight stem made from a first material in a stem mould; and moulding a second portion of the flight stem from a second material in the stem mould together with the first portion. 15 Optional and preferred features are mentioned in the detailed description below and recited in the dependent claims. Brief Description of the Drawings To enable a better understanding of the present invention, and to show how the same may be carried into effect, 5 reference will now be made, by way of example only, to the accompanying drawings, in which:- Figure 1 shows a front perspective view of a first embodiment of a dart flight stem according to the present invention; 10 Figure 2 shows a rear perspective view of the dart flight stem of Figure 1; 15 Figure 3 shows 1; top view of the dart flight stem of Figure CXI Figure 4 shows through the dart cross-sectional view of a horizontal plane flight stem of Figure 1; 20 CXI Figure 5 shows a 1; side view of the dart flight stem of Figure Figure 6 shows a through the dart Figure 7 shows a 1; cross-sectional view of a vertical plane flight stem of Figure 1; 25 rear view of the dart flight stem of Figure Figure 8 shows a front view of the dart flight stem of Figure 3 0    1; Figures 9A to 9C show recessed, flush and proud components along the elongate body of dart flight stems in accordance with various embodiments of the present application; Figures 10 to 13 show a schematic sequence of steps for manufacturing a second embodiment of a dart flight stem shown in Figure 14; Figures 15 to 18 show a schematic sequence of steps for manufacturing a third embodiment of a dart flight stem shown in Figure 19; Figures 20 to 23 show a schematic sequence of steps for manufacturing a fourth embodiment of a dart flight stem shown in Figure 24; Figures 25A to 25E show a schematic sequence of steps for manufacturing a fifth embodiment of a dart flight stem shown in Figure 25F; Figures 26A to 26E show a schematic sequence of steps for manufacturing a sixth embodiment of a dart flight stem shown in Figure 26F; and Figures 27A to 27C and 28A to 28C show embodiments exhibiting variations in the outer surface structure of the dart flight stems of Figures 25F and 26F. Detailed Description The invention will now be described with reference to specific embodiments. It is to be understood that the disclosed embodiments are provided in order to demonstrate one or more ways of putting the invention into effect and that they are in no way to be considered as being limiting on the scope of protection, which is defined solely by the appended claims. Throughout the figures, like reference numerals are used to refer to like components. Figures 1 to 8 show various views of an embodiment of a dart flight stem in accordance with the present invention. Figure 1 shows a front perspective view of the dart flight 5 stem 100. The same embodiment is shown in Figure 2 from a rear perspective view. The dart flight stem 100 includes an elongate body 110. In this embodiment, the elongate body 110 is substantially 10 cylindrical and circular in cross-section, although the present invention is not particularly limited in this respect and other cross-sectional shapes may be. A threaded connector 120 is provided at a front end 112 of 15 the elongate body 110, sized and adapted for releasable interconnection with the back end of a dart barrel (not shown). A set of four petals 130a to 130d extend rearwardly from a 20 back end 114 of the elongate body 110. As best seen in Figure 7, which is a rear view of the dart flight stem 100, the adjacent petals 130a to 130d are separated by a cross-shaped slit formed from a vertical slit 135y and a horizontal slit 135x. This allows a flight to be inserted into the slits from 25 the back end of the petals 130a to 130d and inserted along the cross-slit so as to be held between the petals 130a to 130d. As shown in Figure 1, a series of windows 116a to 116c are 30 formed along the top surface of the elongate body 110, through which a series of projections 142a to 142c extend from within the elongate body 110. The protrusions 142a to 142c form part of an inner portion 140 of the dart flight stem 100, which forms an inner core of the flight stem 100. As can be seen in Figure 1, the projections 142a to 142c are provided as faceted projections extending through the windows 116a to 116c, but remaining broadly within the cross-sectional circumference of the elongate body 110, as can be seen in Figures 7 and 8 (the rear and front views, respectively, of the flight stem 100) . The projections may alternatively extend beyond the circumference of the elongate body 110 or be recessed relative to it. In this embodiment, the flight stem 100 is substantially symmetric, with the windows 116a to 116c and projections 142a to 142c that are visible on the top side of the flight stem 100 in Figure 1 being repeated in mirror image on the underside of the flight stem 100. Although this is not visible in Figures 1 and 2, it can be seen in Figures 5 and 6. The dart flight stem 100 also includes a window or opening 119 on each side of the elongate body 110, near to the front end 112 of the elongate body 110. This window 119 is recessed into the elongate body 110 and provides a through opening through which the inner core portion 140 is visible. Figure 3 shows a top plan view of the dart flight stem 100, while Figure 4 shows a cross-sectional view from the same direction as Figure 3, dissecting through the horizontal central section of the dart flight stem 100. Similarly, Figure 5 shows a side view of the dart flight stem 100, while Figure 6 shows a cross-sectional view from the same direction as Figure 5, through the vertical central section of the dart flight stem 100. It will be appreciated from these Figures that the dart flight stem 100 is formed from two portions, a first, inner core portion 140 and a second, outer portion substantially surrounding the inner core portion 140 and defining the threaded portion 120, the elongate body 110 and the petals 130a to 130d. In this embodiment, the inner core portion 140 is made from a polycarbonate that is substantially transparent or translucent, and which maybe coloured as desired. By contrast the remaining outer portion of the dart flight stem is formed from nylon, which is substantially opaque and may be any desirable colour, such as black. The first, inner core portion 140 allows light to pass through the dart flight stem, between the windows 116a to 116c on the top and bottom sides of the dart flight stem, and also through the windows 119 between the left and right sides of the elongate body 110 (referring to the orientation of the dart flight stem as shown in Figure 1). The projecting portions 142a to 142c are also provided, as shown, with faceted outer surfaces, which provide reflective surfaces that act as a specular component for light that shines on the dart flight stem. In this regard, a specular component is considered to be one which will brightly reflect substantially all frequencies of incident light within the visible spectrum. Of course, the degree of reflection will often change with the angle of incidence. In this context, it is important, when the dart has been thrown and is sticking out of a dart board, for the specular component to reflect light that is incident on the flight stem 100 from a surrounding light ring, or similar light source, backwards towards the player who threw the dart. That is, light impinging on the flight stem 100 from a predominantly radial direction relative to its longitudinal axis will be reflected towards the back end of the flight stem 100. By providing the projections 142a to 142c with faceted outer surfaces as the specular components, they will reflect incident light towards the rear of the flight stem from a variety of incident angles of incoming light. As such, a specular reflection is likely to be directed towards the player who threw the dart from one of the facets, even though the position and angle of the flight stem will vary according to the location of the dart on the target dart board and the angle at which it is sticking out. Radially incident light which is not reflected by the faceted surfaces will tend to enter the windows 116a to 116c and 119 and be reflectively scattered internally within the inner core before exiting the same or another of the windows 116a to 116c and 119. This can give the impression of the flight stem 100 being internally illuminated and to "glow" with the colour of the inner core material. This also improves the visibility of the dart flight stem 100 when sticking out the dart board, for both the player and viewers. Alternatively, the inner core portion 140 may be coated with or made from a reflective material to create a mirror-like surface in which case substantially all of the light incident onto the windows 116a to 116c will be reflected as a specular component. The projections 142a to 142c also provide a tactile benefit to some darts players. Many darts players hold and throw their darts by the barrel; however, some players prefer to grip the flight stem of the dart when making their throw. To this end, the projections 142a to 142c may serve to provide additional grip and / or to provide tactile feedback so that the player can consistently grip the dart stem 100 at the same position, thus being more consistent in their grip and throwing action. Even for players who hold the barrel of the dart, there is often contact with the stem 100 by some part of the player's hand or fingers, and the projections 142a to 142c provide useful tactile feedback to help maintain a consistent grip and throwing action. For this reason, not only faceted outer surfaces, but also grooved or otherwise grip-enhancing designs may be desirable for the outer surface (noting that a grooved outer surface may also be faceted and function as a specular component. The construction of the dart flight stem 100 with a first, inner portion and a second, outer portion not only provides a benefit in terms of visualising and gripping the dart flight stem 100, but also improves rhe structural integrity of the dart flight stem 100. Whilst it would, in principle, be possible to manufacture the entire dart flight stem 100 as a single moulded piece made from polycarbonate, and having similar light reflecting and transmitting properties, such a construction is brittle and will tend to suffer defects whilst playing darts. Common points of failure include the dart flight stem 100 snapping at the front end 112 of the elongate body 110 in the region of the threaded connection 120, where stress concentrations may arise at the interface with the barrel of a dart into which the flight stem 100 is screwed. Stress concentrations also arise at the bases 132a to 132d of the respective petals 130a to 130d. The petals 132a to 130d may snap off at their bases 132a to 132d if made from a brittle material such as polycarbonate, for example if the dart bounces out of the dart board and lands on the floor, or if a subsequent thrown dart impacts against the rear of the dart flight stem 100 whilst it is sticking out of the dart board. The embodiment of the present invention shown in Figures 1 to 8 overcomes the potentially negative structural limitations of the polycarbonate material used for the first, inner core portion 140 by providing a resilient outer portion which surrounds the inner core 140 and provides the dart flight stem 100 with structural integrity. In this regard, it can be seen that the second, outer portion substantially entirely surrounds the first, inner portion 140 except in the region of the windows 116a to 116c and 119. It is to be noted that the material of the second outer portion which forms the elongate body 110 should be made of sufficiently thick material to form a strong support structure for the inner core 140. The design and construction of the dart flight stem as a whole also has to be considered, and it will be noted that support bars 118a and 118b of the elongate body 110 extend across the inner portion 140 between the lateral sides of the elongate body 110 so as to provide structural support between the windows 116a and 116b and between the windows 116b and 116c, respectively. These support bars 118a and 118b have to be of sufficient size and dimension, typically no smaller than l±0.1 mm in width, in order to provide structural support to the inner core 140 during the normal use of the darts, i.e. when thrown at a dart board (often with significant force) and when subjected to impacts from other darts or when the thrown dart bounces out of the dart board. In the present embodiment, the inner portion 140 is shown extending forward through the centre of the threaded connection portion 120. In the case of the inner portion 140 being made of transparent or translucent material, this may be used to provide a light guide from the front of the threaded connection portion 120 into the interior of the flight stem 100. A light source provided in the barrel of the dart, for example an LED with an associated battery housed in the dart barrel, may then be used to light the flight stem 100 and projections 142a to 142c from the inside. Actively shining light out of windows 116a to 116c in this manner may also assist the darts player and viewers in seeing the dart projecting from the dart board. In the more usual case where there is no active light source in the dart barrel, for reasons of structural integrity of the flight stem, it will instead be preferable for the inner portion 140 to terminate short of the threaded connection portion 120 and for the second material of the outer portion to form the whole of the threaded connection portion, extend along the full length of the elongate body 110, and form the petals 132a to 132d, including the bases thereof, as a continuous integral moulded part. In the present embodiment, the material forming the second, outer portion is nylon. In this specification, any mention of nylon includes reference to carbon-loaded nylon, which may have a carbon loading of approximately 10±5% by volume. Nylon has adequate strength and resilience to withstand the impacts encountered during normal darts play, and in particular to resist brittle fractures occurring at the region of the front end 112 of the elongate body 110 where it joins to the threaded connection portion 120 or at the bases 132a to 132d of the petals 130a to 130d. Nylon will tend to deform plastically when subjected to high loads and stress concentrations, rather than snapping in a brittle manner. This will often prevent the dart flight stem 100 from breaking and allow it to continue to be used. The second, outer portion thus acts as a support cage or frame for the first, inner core, in much the same way as the steel reinforcement bars in reinforced concrete or the fibres in carbon fibre or GFRP. That is, the composite structure benefits from the respective material properties of its component parts that support each other. In this regard, it will be clear that the specific construction shown in Figures 1 to 8 is exemplary only and that many modifications are be possible using the same constructional concepts. For example, the dart flight stem could have a resilient central core that extends along its length and includes the threaded front portion 120 and all or part of the petals 130a to 130d, combined with and a more bristle material forming the outer part of the elongate body 110. Of course, there are many different material combinations that can provide advantage to a darts player beyond the combination of a specular component supported by, in or on a resilient cage or frame. For example, projections or nodules of a frictional elastomeric material, such as rubber, could be formed on the outer surface of a flight stem of a different, less frictional material to improve the grip between the flight stem and a player's fingers or hand. Similarly, two materials with similar or identical physical and chemical properties but which are different colours, for example due to different colouring additives being used in each material, could be combined to form a flight stem with a defined pattern on its outer surface. Alternatively, the inner portion may be formed from a metal alloy and the second outer portion may be formed from a thermoplastic material, or vice versa. In order to manufacture the dart flight stem 100 shown in Figures 1 to 8, the first, inner core portion 140 is first moulded. This component can relatively simply be formed in a core mould by any known moulding technique, in this case using polycarbonate or another mouldable thermoplastic material. The moulded inner core 140 is then placed in a stem mould. The stem mould is typically formed of upper and lower halves, although the invention is not limited in this respect. The inner core 140 is installed in the lower mould half and the upper mould half is closed over it to clamp the inner core 140 in place within the mould. Nylon is then injected into the closed stem mould around the inner core. Although not limited in this respect, the nylon is injected into the stem mould from the front end of the flight stem towards the petals at the back end. Injection moulding involves injecting molten thermoplastic material into the mould at high pressure, and it is therefore important to stabilise the inner core 140 within the stem mould during the injection process. To this end, the stem mould is formed to fit tightly and accurately around the exposed faceted portions of projections 142a to 142c when closed around the inner core 140. The mould is also configured to clamp the inner core 140 on each side in the region corresponding to the windows 119. This provides further lateral stability to the inner core 140 during the injection moulding process and reduces the rate of manufacturing defects. By this process, which may be thought of as an over-moulding process, the second, outer portion forming the threaded connector 120, elongate body 110 and petals 130a to 130d is co-moulded with the inner core 140. The inner core is mechanically encapsulated within the structural frame formed by the second, outer portion and the two portions may also become heat-bonded together by this process in the event that the melting point of the outer portion is higher than the melting or softening point of the inner portion. It will be appreciated that similar techniques may be used whenever two different materials are to be co-moulded to form a dart flight stem. Of course, it is not a requirement for the inner core 140 itself to be moulded, and the inner core could, for example, equivalently be formed by a glass, ceramic or metal component, or even a jewel such as a diamond. Similarly, more than one inner core member could be installed in the mould and combined into the flight stem by the injection moulding process, providing that each member is adequately supported by the eventual moulded frame and is securely held in the mould during the moulding process. Other techniques can also be used for co-moulding the two portions of the flight stem. For example, portions of a mould may be filled with a first material of a first colour or material property, and the remainder of the mould filled with a second material of a second colour or material property. The mould is then closed and heat treated to comould the materials together. A further example may involve co-extruding the two materials or simultaneously injecting them into a mould, depending on the desired effect and construction. The term co-moulding is intended to encompass all such processes whereby moulding at least one of the portions results in a unitary, integrally formed body. Alternatively, one, two or more materials can be 3D-printed using a computer-controlled 3D printer to deposit drops of molten material which join and solidify to form individual layers of the flight stem. 3D printing allows relatively complex structures and shapes comprising of multiple materials to be built up in this way, layer by layer. A 3D-printed portion may also be integrated with another component by 3D-printing onto that component as a base substrate, or by co-moulding the moulded component together with the already-printed portion in a similar manner as described above. Whilst described with reference to the embodiment shown in Figures 1 to 8, it should be appreciated that flight stems according to the present invention may have many different forms. For example, there is no restriction to the use of only first and second portions formed of different materials, and the flight stem may include three or more materials comoulded to form the flight stem. In this context, the first and second materials may be the "same material" in terms of their essential prevalent chemical composition but are nevertheless considered to be different materials if they are differentiated by one or more relevant material properties or by their colour or opacity. For example, both materials could be nylon, but with one having an additive to change its colour or frictional properties. The other material might then have no additive or might have one or more different additives. A second embodiment of a dart flight stem 200 according to the present invention is illustrated in side view in Figure 14, whilst Figures 10 to 13 show schematically a sequence of steps in a method of manufacturing the dart flight stem 200. In these figures, the same reference numerals are used for corresponding and like components as in the embodiment of Figures 1 to 8, but with the reference numeral increased by 100 . As shown in Figure 14, this embodiment of the dart flight stem 200 includes an elongate body 210 having a front end 212 and a back end 214. A threaded connection portion 220 is formed at the front end 212. At the back end 214 of the elongate body 210, petals 230a to 230d extend rearwardly from their bases and define cross-slit 235x,y therebetween for receiving and holding the dart flight. In this embodiment, a first portion 240 is provided which is formed as a spiral of a first material. The spiral is interwound within a spiral of a second material, which second material forms the threaded connection portion 220, the remainder of the elongate body 210, and the petals 230a to 230d as an integrally formed unitary body. The first and second materials may be any of the materials, and combinations of materials, described above. For example, the spiral first portion 240 night be made of transparent or translucent polycarbonate, while the second portion is formed of opaque nylon. Alternatively, both materials may be nylon but coloured differently so as to exhibit a spiral pattern on the outer surface of the elongate body 210. It will also be appreciated that while the first portion 240 is shown having an outer surface that will form a flush outer surface of the elongate body 210, either or both of the first and second portions could instead be formed with projecting outer surfaces forming ridged, grooved or otherwise textured and / or faceted surfaces for example for providing grip and / or light reflection, as described above. Exemplary embodiments of such dart flight stems 200A, 200B and 200C having first portions 240A, 240B and 240C that are respectively recessed, flush and proud with respect to the outer surface of the remainder of the elongate body are shown in Figures 9A to 9C. Figure 9A shows a dart flight stem 200A, in which the second portion that forms the threaded connection portion 220, the remainder of the elongate body 210, and the petals 230a to 230d has an identical construction to the second portion of the flight stem 200 shown in Figure 14. However, in this embodiment, the first portion 240A has a reduced radial extent so as to be recessed with respect to the outer surface of the elongate body 210, inside the spiral window 216. Whilst a flat outer surface of the first portion 240a is shown (when viewed from the side, as seen in Figure 9A), it will be appreciated that the shape of the outer surface of the first portion 240A is not limited, and may, for example, be formed as a V-shaped groove or any other faceted shape. Equally, not all parts of the outer surface of the first portion 240A need be recessed. In the example of a V-shaped groove, the edges of the outer surface of the first portion 240A may be flush with the outer surface of the elongate body 210 at the edges of the windows 216 to provide a continuous surface at the interface. Figure 9B shows a dart flight stem 200B, which is identical in construction to the dart flight stem 200 shown in Figure 14. It is shown here alongside the dart flight stems 200A and 200C of Figures 9A and 9C to permit direct comparison therebetween. Figure 9C shows a dart flight stem 200C, in which the second portion that forms the threaded connection portion 220, the remainder of the elongate body 210, and the petals 230a to 230d has an identical construction to the second portion of the flight stem 200 shown in Figure 14. However, in this embodiment, the first portion 240C has an increased radial extent so as to project radially outwardly with respect to the outer surface of the elongate body 210. In this example, the first portion 240C presents a V-shaped projection in side view, as seen in Figure 9C, although the present invention is not limited in this regard and any other cross-sectional shape may be employed, such as a U-shaped dome or a multi-faceted shape. In all of the examples of Figures 9A to 9C, a constant cross-sectional shape is assumed for each of the first portions 240A to 240C. However, it is not a requirement for the first portions 240A to 240C to have a constant cross-sectional shape, and the outer surface of the first portions 240A to 240C may vary along the length of the spiral or around the circumference of the dart flight stems 200A to 200C. It is also contemplated that the outer surface may of the first portions may be recessed in parts, and / or flush in other parts and / or proud in other parts. Referring to Figures 10 to 13, a method of manufacturing the flight stem 200 is illustrated schematically by a sequence of steps set out in order in Figures 10 to 13. These figures show a cross-sectional view onto a vertical plane through the mould 1300 that contains the longitudinal axis of the dart flight stem 200. Figure 10 is a cross-sectional view, showing a spiral inner core component 240 placed into an open stem mould 1300 consisting of a lower stem mould part 1310 and an upper stem mould part 1320. The mould parts 1310 and 1320 include respective mould cavities 1312 and 1322 corresponding to the outer surface shape of the moulded flight stem 200. The inner core component 240 nay have been formed by moulding in a core mould, or by any other means, including 3D printing. The material of the inner core component 240 is not particularly limited, and it may be any of the materials discussed above. The inner core component 240 is also not limited to a single component made of a single material, and embodiments of the present invention may also include multiple inner core components, for example a series of rings instead of a continuous spiral, of the same or different materials from one another. Embodiments may also or alternatively include inner core components made from more than one material; for example, the spiral component 240 could have other components formed on and / or within it, such as jewels, lettering or specular components arranged to reflect light. As shown in Figure 11, the mould 1300 is closed so that the inner core component 240 is held clamped between the lower and upper mould parts 1310 and 1320. The designations "lower" and "upper" refer to the disposition of the mould parts as shown in Figures 10 to 13. Whilst it is preferred to have a stably supported lower mould part 1310 and an opening / closing upper mould part 1320, the invention is not limited in this respect, and any mould orientation may be used. Similarly, the invention is not limited to the use of two-part moulds, and moulds with three or more parts may also be used. The mould parts 1310 and 1320 serve to stabilise the position of the inner core component 240 during the injection phase. As shown in Figure 12, after the mould is closed, the second material is injected into the mould in liquid form so as to fill all remaining portions of the mould cavities 1312, 1322. As the injection is done under high pressure, the stem mould 1300 has to provide a strong clamping force to hold the inner core component 240 in place and so prevent or eliminate production defects. After allowing the injected second material to solidify, the second material has been co-moulded with the first component 240 to form an integral body of the flight stem. The mould 1300 can then be opened, in this case by lifting the upper mould part 1320 to separate it from lower mould part 1310, and the moulded flight stem 200 can be extracted. It will also be appreciated that, in an alternative method, the hashed second component shown in Figures 12 to 14 could be provided as the inner core component and placed into stem mould 1300, and the first material then be injected into the mould 1300 into the spiral groove formed in this component in order to co-mould the component 240 with the rest of the flight stem. As noted with the embodiment of Figures 1 to 8, the flight stem 200 of this embodiment may benefit from increased structural integrity by virtue of the second material being a more resilient material and forming the threaded connection portion 220, the petals 230a to 230d and the bases thereof, as well as the central stem of the elongate body 210, thereby providing an continuous unitary body of resilient material that provides a frame for carrying the spiral first component 240. First component 240 may be made of another more brittle material, and is supported by the resilient frame provided by the second material so as to resist fracturing at stress concentration points. Equally, the material of the first component may be selected to enhance visibility of the dart flight stem 200 in a dart board as compared to a flight stem made only of the second material. A third embodiment of a dart flight stem 300 according to the present invention is illustrated in side view in Figure 19, whilst Figures 15 to 18 show schematically a sequence of steps in a method of manufacturing the dart flight stem 300. Dart flight stem 300 is identical to the exemplary dart flight stem 200C shown in Figure 9C above. In these figures, the same reference numerals are used for corresponding and like components as in the embodiment of Figures 10 to 14, but with the reference numeral increased by 100 . As shown in Figure 19, this embodiment of the dart flight stem 300 includes an elongate body 310 having a front end 312 and a back end 314. A threaded connection portion 320 is formed at the front end 312. At the back end 314 of the elongate body 310, petals 330a to 330d extend rearwardly from their bases and define cross-slit 335x,y therebetween for receiving and holding the dart flight. In this embodiment, a first portion 340 is again provided which is formed as a spiral of a first material. The spiral is inter-wound within a spiral of a second material, which second material forms the threaded connection portion 320, the remainder of the elongate body 310, and the petals 330a to 330d as an integrally formed unitary body. The first and second materials may be any of the materials, and combinations of materials, described above. For example, the spiral first portion 340 night be made of transparent or translucent polycarbonate, while the second portion is formed of opaque nylon. Alternatively, both materials may be nylon but coloured differently so as to exhibit a spiral pattern on the outer surface of the elongate body 310. Referring to Figures 15 to 18, a method of manufacturing the flight stem 300 is illustrated schematically by a sequence of steps set out in order in Figures 15 to 18. These figures 5 show a cross-sectional view onto a vertical plane through the mould 1400 that contains the longitudinal axis of the dart flight stem 300. 10 20 25 30 Figure 15 is a cross-sectional view, showing a spiral inner core component 340 placed into an open stem mould 1400 consisting of a lower stem mould part 1410 and an upper stem mould part 1420. The mould parts 1410 and 1420 include respective mould cavities 1412 and 1422 corresponding to the outer surface shape of the moulded flight stem 300. The inner core component 340 nay have been formed by moulding in a core mould, or by any other means, including 3D printing. The material of the inner core component 340 is not particularly limited, and it may be any of the materials discussed above. The inner core component 340 is also not limited to a single component made of a single material, and embodiments of the present invention may also include multiple inner core components, for example a series of rings instead of a continuous spiral, of the same or different materials from one another. Embodiments may also or alternatively include inner core components made from more than one material; for example, the spiral component 340 could have other components formed on and / or within it, such as jewels, lettering or specular components arranged to reflect light. As shown in Figure 16, the mould 1400 is closed so that the inner core component 340 is held clamped between the lower and upper mould parts 1410 and 1420. The designations 35 "lower" and "upper" refer to the disposition of the mould parts as shown in Figures 15 to 18. Whilst it is preferred to have a stably supported lower mould part 1410 and an opening / closing upper mould part 1420, the invention is not limited in this respect, and any mould orientation may be used. Similarly, the invention is not limited to the use of two-part moulds, and moulds with three or more parts may also be used. The mould parts 1410 and 1420 serve to stabilise the position of the inner core component 340 during the injection phase. As shown in Figure 17, after the mould is closed, the second material is injected into the mould in liquid form so as to fill all remaining portions of the mould cavities 1412, 1422. As the injection is done under high pressure, the mould 1400 has to provide a strong clamping force to hold the inner core component 340 in place and so prevent or eliminate production defects . After allowing the injected second material to solidify, the second material has been co-moulded with the first component 340 to form an integral body of the flight stem. The mould 1400 can then be opened, in this case by lifting the upper mould part 1420 to separate it from lower mould part 1410, and the moulded flight stem 300 can be extracted. It will also be appreciated that, in an alternative method, the hashed second component shown in Figures 17 to 19 could be provided as the inner core component and placed into stem mould 1400, and the first material then be injected into the mould 1400 into the spiral groove formed in this component in order to co-mould the component 340 with the rest of the flight stem. As noted with the preceding embodiments, the flight stem 300 of this embodiment may benefit from increased structural integrity by virtue of the second material being a more resilient material and forming the threaded connection portion 320, the petals 330a to 330d and the bases thereof, as well as the central stem of the elongate body 310, thereby providing an continuous unitary body of resilient material that provides a frame for carrying the spiral first component 340. First component 340 may be made of another more brittle material, and is supported by the resilient frame provided by the second material so as to resist fracturing at stress concentration points. Equally, the material of the first component may be selected to enhance visibility of the dart flight stem 300 in a dart board as compared to a flight stem made only of the second material. Although not separately illustrated, the same manufacturing process and principles described above for the flight stems 200 and 300 can be used for moulding a dart flight stem 200A having a first portion 240A that is recessed relative to the outer surface of the elongate body 210, instead of being proud thereof or flush therewith. A fourth embodiment of a dart flight stem 400 according to the present invention is illustrated in side view in Figure 24, whilst Figures 20 to 23 show schematically a sequence of steps in a method of manufacturing the dart flight stem 400. In these figures, the same reference numerals are used for corresponding and like components as in the embodiment of Figures 15 to 19, but with the reference numeral increased by 100 . As shown in Figure 24, this embodiment of the dart flight stem 400 includes an elongate body 410 having a front end 412 and a back end 414. A threaded connection portion 420 is formed at the front end 412. At the back end 414 of the elongate body 410, petals 430a to 430d extend rearwardly from their bases and define cross-slit 435x,y therebetween for receiving and holding the dart flight. In this embodiment, a first portion 440 is provided which is formed as a cylindrical tube of a first material. The cylindrical tube 440 sits around a central core 450 of a second material, which second material forms the threaded connection portion 420, the remainder of the elongate body 410, and the petals 430a to 430d as an integrally formed 5 unitary body. The first and second materials may be any of the materials, and combinations of materials, described above. For example, the cylindrical first portion 440 might be made of 10 transparent or translucent polycarbonate, while the second portion is formed of opaque nylon. Alternatively, both materials may be nylon but coloured differently so as to exhibit a changing colour pattern on the surface of the elongate body 410. 15 CXI 20 CXI Referring to Figures 20 to 23, a method of manufacturing the flight stem 400 is illustrated schematically by a sequence of steps set out in order in Figures 20 to 23. These figures show a cross-sectional view onto a vertical plane through the mould 1500 that contains the longitudinal axis of the dart flight stem 400. Figure 15 is a cross-sectional view, showing cylindrical tube component 440 placed into an open stem mould 1500 consisting 25 of a lower stem mould part 1510 and an upper stem mould part 1520. The mould parts 1510 and 1520 include respective mould cavities 1512 and 1522 corresponding to the outer surface shape of the moulded flight stem 400. 30 The cylindrical tube component 440 may have been formed by moulding in a tube mould, or by any other means, including 3D printing. The material of the cylindrical tube component 440 is not particularly limited, and it may be any of the materials discussed above. The cylindrical tube component 35  440 is also not limited to a single component made of a single material, and embodiments of the present invention may also include multiple cylindrical tube components, for example a series of rings, either in abutment with one another or spaced along the elongate body, instead of a continuous tube, or a series of coaxial tubes, of the same or different materials from one another. Embodiments may also or alternatively include cylindrical tube components made from more than one material; for example, the cylindrical tube component 440 could have other components formed on and / or within it, such as jewels, lettering or specular components arranged to reflect light. It will also be appreciated that the cylindrical tube component 440 need not be cylindrical but could be any shape having one or more through holes, or a network of interconnected passages, extending from the front to the back of the component. In this regard, the component could exhibit a central "trunk" extending end-to-end along the component, with "branches" extending radially outwardly. These branches could extend entirely through the thickness of the tubular component so as to extend to the outer surface of the elongate body 410. In another arrangement, the internal cavity within the tube could form desirable shapes such as a logo or lettering. Similarly, the outer surface of the tubular component could be smooth and continuous, as illustrated, or could be formed with a series of ridges or grooves (or both), or any other pattern or shape, such as a faceted specular surface. As shown in Figure 20, the mould 1500 is closed so that the cylindrical tube component 440 is held clamped between the lower and upper mould parts 1510 and 1520. The designations "lower" and "upper" refer to the disposition of the mould parts as shown in Figures 20 to 23. Whilst it is preferred to have a stably supported lower mould part 1510 and an opening / closing upper mould part 1520, the invention is not limited in this respect, and any mould orientation may be used. Similarly, the invention is not limited to the use of two-part moulds, and moulds with three or more parts may also be used. The mould parts 1510 and 1520 serve to stabilise the position of the cylindrical tube component 440 during the injection phase. As shown in Figure 22, after the mould is closed, the second material is injected into the mould in liquid form so as to fill all remaining portions of the mould cavities 1512, 1522, as well as each cavity or network of cavities that extends through the cylindrical tube component 440. In this way, the central core 450 is formed integrally with the remaining portions at the front and back ends of the dart flight stem 400. As the injection is done under high pressure, the mould 1500 has to provide a strong clamping force to hold the cylindrical tube component 440 in place and so prevent or eliminate production defects. After allowing the injected second material to solidify, the second material has been co-moulded with the cylindrical tube component 440 to form an integral body of the flight stem. The mould 1500 can then be opened, in this case by lifting the upper mould part 1520 to separate it from lower mould part 1510, and the moulded flight stem 400 can be extracted. It will also be appreciated that, in an alternative method, the hashed second component shown in Figures 22 to 24 could be provided as the inner core component and placed into stem mould 1500, and the first material then be injected into the mould 1500 into the tubular space around the central core 450 in order to co-mould the component 440 with the rest of the flight stem. As noted with the preceding embodiments, the flight stem 400 of this embodiment may benefit from increased structural integrity by virtue of the second material being a more resilient material and forming the threaded connection portion 420, the petals 430a to 430d and the bases thereof, as well as the central core 450 of the elongate body 410, thereby providing an continuous unitary body of resilient material that provides a frame for carrying the cylindrical tube component 440. The first, cylindrical tube component 440 may be made of another more brittle material, and is supported by the resilient support structure provided by the second material so as to resist fracturing at stress concentration points. Equally, the material of the first component 440 may be selected to enhance visibility of the dart flight stem 400 in a dart board as compared to a flight stem made only of the second material. A fifth embodiment of a dart flight stem 500 according to the present invention will now be described with reference to Figures 25A to 25F. In these figures, the same reference numerals are used for corresponding and like components as in the embodiment of Figures 20 to 24, but with the reference numeral increased by 100 . As shown in side view Figure 25F, this embodiment of the dart flight stem 500 includes an elongate body 510 having a front end 512 and a back end 514. A threaded connection portion 520 is formed at the front end 512. At the back end 514 of the elongate body 510, petals 530a to 530d extend rearwardly from their bases and define cross-slit 535x,y therebetween for receiving and holding the dart flight. In this embodiment, a first portion is provided which is formed as a cylindrical tube of a first material. The cylindrical tube sits around a central core 550 of a second material (see Figures 25D and 25E), which second material also forms the threaded connection portion 520, the remainder of the elongate body 510, and the petals 530a to 530d as an integrally formed unitary body. In this embodiment, the cylindrical tube is formed from two parts - an upper half 540a and a lower half 540b (referring to the orientation shown in Figures 25A to 25F). The first and second materials may be any of the materials, and combinations of materials, described above. For example, the two halves of the cylindrical first portion 540a,b might be made of transparent or translucent polycarbonate, while the second portion is formed of opaque nylon. Alternatively, both materials may be nylon but coloured differently so as to exhibit a changing colour pattern on the surface of the elongate body 510. It is also possible for the upper half 540a and the lower half 540b to be formed from the same material or from different materials. Figure 25A shows a cross-sectional view of the dart flight stem 500 onto a vertical plane that contains the longitudinal axis of the dart flight stem 500. Figures 25B and 25C show the upper and lower halves 540a,b, respectively from the front end and from the rear end of the cylindrical first portion. As shown in Figures 25A to 25C, the upper and lower halves 540a,b are initially formed separately from the second portion of the flight stem, including central core 550. In this embodiment, the upper half 540a and lower half 540b are formed with interlocking connections in the form of protrusions 542a and 542b and recesses 544a and 544b, respectively. The two halves 540a,b of the cylindrical first portion are then closed around the central core 550, as shown in Figures 25D and 25E. Figure 25D shows a cross-sectional view of the dart flight stem 500 onto a vertical plane that contains the longitudinal axis of the dart flight stem 500. Figure 25E shows a cross-sectional view through the flight stem 500 onto a vertical plane that is perpendicular to the longitudinal axis, at any point along the length of the cylindrical first portion. The interlocking connections provide an interference fit when the protrusion 542a of the upper half 540a is inserted into the recess 544b of the lower half 540b, and when the protrusion 542b of the lower half is inserted into the recess 544a of the upper half 540a, as shown in Figure 25E. The interference fit may be frictional or may rely on a snap-fit connection. Glue or other adhesives may also be used to secure the connection between the upper and lower halves. Whilst the example shown has a protrusion and a recess on opposite sides of each of the upper and lower halves, which may reduce manufacturing complexity as one mould will provide the pieces for both halves, one half could instead have protrusions on both sides and the other half could have recesses on both sides. Similarly, it is not necessary for the protrusions and recesses to extend the full length of the cylindrical component, and they may be provided only along part of the length of each half. Each half 540a,b, and each side of each half 540a,b, may have multiple protrusions and recesses aligned with recesses and protrusions on the opposed, mating half, without particular limitation. A sixth embodiment of a dart flight stem 600 according to the present invention will now be described with reference to Figures 26A to 26F. In these figures, the same reference numerals are used for corresponding and like components as in the embodiment of Figures 25A to 25F, but with the reference numeral increased by 100. As shown in side view Figure 26F, this embodiment of the dart flight stem 600 includes an elongate body 610 having a front end 612 and a back end 614. A threaded connection portion 620 is formed at the front end 612. At the back end 614 of the elongate body 610, petals 630a to 630d extend rearwardly from their bases and define cross-slit 635x,y therebetween for receiving and holding the dart flight. In this embodiment, a first portion is provided which is formed as a cylindrical tube of a first material. The cylindrical tube sits around a central core 650 of a second material (see Figures 26D and 26E), which second material also forms the threaded connection portion 620, the remainder of the elongate body 610, and the petals 630a to 630d as an integrally formed unitary body. In this embodiment, the cylindrical tube is formed from two parts - an upper half 640a and a lower half 640b (referring to the orientation shown in Figures 26A to 26F). The first and second materials may be any of the materials, and combinations of materials, described above. For example, the two halves of the cylindrical first portion 640a,b might be made of transparent or translucent polycarbonate, while the second portion is formed of opaque nylon. Alternatively, both materials may be nylon but coloured differently so as to exhibit a changing colour pattern on the surface of the elongate body 610. It is also possible for the upper half 640a and the lower half 640b to be formed from the same material or from different materials. Figure 26A shows a cross-sectional view of the dart flight stem 600 onto a vertical plane that contains the longitudinal axis of the dart flight stem 600. Figures 26B and 26C show the upper and lower halves 640a,b, respectively from the front end and from the rear end of the cylindrical first portion. As shown in Figures 26A to 26C, the upper and lower halves 640a,b are initially formed separately from the second portion of the flight stem, including central core 650. In this embodiment, the upper half 640a and lower half 640b are formed with end connections in the form of front protrusions 648a and 848b and rear protrusions 646a and 646b, at their front and rear ends respectively. The front and rear protrusions are sized to form an interference fit with corresponding front recesses 658a, 658b and rear recesses 656a, 656b, respectively formed in the front and rear ends of the second portion of the dart flight stem 600 at each end of the central core 650. The two halves 640a,b of the cylindrical first portion are then closed around the central core 650, as shown in Figures 26D and 26E. Figure 26D shows a cross-sectional view of the dart flight stem 600 onto a vertical plane that contains the longitudinal axis of the dart flight stem 600. Figure 26E shows a cross-sectional view through the flight stem 600 onto a vertical plane that is perpendicular to the longitudinal axis, at any point along the length of the cylindrical first portion. The end connections provide an interference fit when the protrusion 646a and 648a of the upper half 640a are inserted into the recess 656a and 658a, and when protrusion 646b and 648b of the upper half 640b are inserted into the recess 656b and 658b, as shown in Figure 26D. The interference fit may be frictional or may rely on a snap-fit connection. Glue or other adhesives may also be used to secure the connection between the upper and lower halves 640a and 640b of the first portion and the recesses of the second portion. Whilst the example shown has protrusions at each end of each half 640a,b of the cylindrical portion, with a recess in the second portion at each end of the central core 650, the protrusions and recesses are functionally interchangeable and so protrusions or recesses may be provided on either or both ends of both halves 640a,b of the cylindrical portion, with corresponding recesses and protrusions provided on the second portion at each end of the cylindrical core 650. Each half 640a,b, and each end of each half 640a,b, may similarly have multiple protrusions and recesses aligned with recesses and protrusions on the opposed, mating end of the first portion. It will of course be appreciated that the mating protrusions and recesses of the fifth and sixth embodiments may be combined such that there is an interference fit between the two halves of the cylindrical portion and between the ends of the cylindrical portion and the second portion of the flight stem. In further embodiments, not interference fit is required, and the two halves of the cylindrical portion and / or the second portion are joined by adhesive, laser welding or any other method. It will furthermore be appreciated that the constructional details described with reference to Figures 25A to 25F and 26A to 26F may be applied to a wide variety of shapes and that the cylindrical structure described and illustrated is given merely as an example. Figures 27A to 27C show variations of the foregoing embodiments in which the cylindrical part has protrusions provided along its outer surface, which may provide grip and / or form a faceted surface acting as a specular component. Figure 27C is a side view that is identical for two embodiments, the first being an adaptation, 500A, of the flight stem 500 and the second being an adaptation, 600A, of the flight stem 600. Respective views of flight stems 500A and 600A are shown in Figures 27A and 27B, respectively, each showing a cross-sectional view of the dart flight stem 500A / 600A onto a vertical plane that contains the longitudinal axis of the dart flight stem 500A / 600A. Besides the protrusions on the outer surface of the upper and lower halves 540Aa and 540Ab of the cylindrical component, the constructional details of the dart flight stem 500A are identical as for the dart flight stem 500, including the provision of protrusions and recesses along the mating faces of the upper 540Aa and lower 540Ab halves, in the same manner as shown in Figures 25B, 25C and 25E. Similarly, besides the protrusions on the outer surface of the upper and lower halves 640Aa and 640Ab of the cylindrical component, the constructional details of the dart flight stem 600A are identical as for the dart flight stem 600. In particular, this embodiment includes protrusions 646Aa, 648Aa and protrusions 646Ab,648Ab at the rear and front end faces, respectively, of the upper 640Aa and lower 640Ab halves of the cylindrical portion, and mating upper and lower front recesses 658Aa, 658Ab and upper and lower rear recesses 656Aa, 656Ab formed in the second portion at both ends of the central core 650A, in the same manner as shown in Figures 26A to 26D. Figures 28A to 28C show variations of the foregoing embodiments in which the cylindrical part has grooves or recesses provided along its outer surface, which may provide grip and / or form a faceted surface acting as a specular component. Figure 28C is a side view that is identical for two embodiments, the first being an adaptation, 500B, of the flight stem 500 and the second being an adaptation, 600B, of the flight stem 600. Respective views of flight stems 500B and 600B are shown in Figures 28A and 28B, respectively, each showing a cross-sectional view of the dart flight stem 500B / 600B onto a vertical plane that contains the longitudinal axis of the dart flight stem 500B / 600B. Besides the grooves or recesses in the outer surface of the upper and lower halves 540Ba and 540Bb of the cylindrical component, the constructional details of the dart flight stem 500B are identical as for the dart flight stem 500, including the provision of protrusions and recesses along the mating faces of the upper 540Ba and lower 540Bb halves, in the same manner as shown in Figures 25B, 25C and 25E. Similarly, besides the grooves or recesses in the outer surface of the upper and lower halves 640Ba and 640Bb of the cylindrical component, the constructional details of the dart flight stem 600B are identical as for the dart flight stem 600. In particular, this embodiment includes protrusions 646Ba, 648Ba and protrusions 646Bb,648Bb at the rear and front end faces, respectively, of the upper 640Ba and lower 640Bb halves of the cylindrical portion, and mating upper and lower front recesses 658Ba, 658Bb and upper and lower rear recesses 656Ba, 656Bb formed in the second portion at both ends of the central core 650B, in the same manner as shown in Figures 26A to 26D. Many adaptations of the principles and concepts outlined above will be apparent to the skilled person in view of the teaching contained herein. All such variations within the scope of the appended claims and their equivalents as properly assessed are intended to fall within the scope of protection defined by the claims.

Claims

1. A dart flight stem comprising a first portion and a second portion, wherein the first portion is formed from a first material and the second portion is moulded from a second material different from the first material, wherein the first portion is formed as a core and the second material is moulded onto and / or around the core of first material to form the second portion.

2. A dart flight stem according to Claim 1, wherein the first portion is moulded or 3D-printed from the first material.

3. A dart flight stem according to Claim 1 or 2, wherein the first portion and the second portion are integrally formed as a unitary body.

4. A dart flight stem according to Claim 1, 2 or 3, wherein the first material and the second material are comoulded .

5. A dart flight stem according to any preceding claim, wherein the second portion includes a plurality of second portions formed on the outside of the first portion.

6. A dart flight stem according to any preceding claim, wherein the core includes one or more projections extending radially from a substantially cylindrical or prismatic elongate central body, and wherein the second portion substantially covers and / or surrounds the central body but not the one or more projections suchthat they are exposed at least at their radially outer surfaces .

7. A dart flight stem according to Claim 6, wherein the one or more projections includes at least two projections, and wherein the at least two projections extend from the elongate central body in different radial directions.

8. A dart flight stem according to Claim 7, wherein the radial directions are substantially 60 degrees, 90 degrees, 120 degrees or 180 degrees apart with respect to a longitudinal axis of the central body.

9. A dart flight stem according to Claim 7 or 8, wherein at least one of the one or more projections is formed with a faceted or grooved outer surface.

10. A dart flight stem according to any preceding claim, wherein one of the first and second portions is substantially transparent or translucent and the other of the first and second portions is substantially opaque .

11. A dart flight stem according to any preceding claim, wherein one of the first and second materials is relatively resilient and the other of the first and second materials is relatively brittle.

12. A dart flight stem according to Claim 11, wherein the portion of relatively resilient material reinforces the portion of relatively brittle material.

13. A dart flight stem according to any preceding claim, wherein the flight stem includes an elongate body having a front end with a threaded connection portion and a back end with petals projecting rearwardly from bases thereof .

14. A dart flight stem according to Claim 13, wherein a region of the flight stem immediately adjacent the threaded connection portion and / or a region immediately at and adjacent the base of each of the petals is formed from the second material.

15. A dart flight stem according to Claim 14, wherein the threaded connection portion, the petals, the immediately adjacent portions of the elongate body, and a portion of the elongate body extending therebetween are integrally formed from the second material.16.17 .A dart flight stem according to Claim 14 or 15 as dependent directly or indirectly from Claim 11, wherein the second material is relatively resilient and the first material is relatively brittle.A dart flight stem according to any preceding claim, wherein the first material is a translucent plastic, which may be polycarbonate, and the second material is an opaque polymer, which may be nylon.

18. A dart flight stem according to any preceding claim, wherein the first material and the second material have substantially the same chemical composition but at least one of the first and second materials includes an additive so that it is a different colour and / or opacity from the first material.

19. A method of manufacturing a dart flight stem comprising: providing a first portion of the flight stem made from a first material in a stem mould; andmoulding a second portion of the flight stem from a second material in the stem mould together with the first portion,wherein moulding the second portion includes injecting the second material into the stem mould onto and / or around the first portion to form the second portion.

20. A method of manufacturing a dart flight stem according to Claim 19, wherein moulding the second portion includes injection moulding the second portion by injecting the second material into the stem mould.

21. A method of manufacturing a dart flight stem according to Claim 19 or 20, wherein providing the first portion includes moulding the first portion in a first portion mould or 3D-printing the first portion with a 3D-printer.

22. A method of manufacturing a dart flight stem according to Claim 19, 20 or 21, wherein providing the first portion includes placing the first portion in the stem mould in an open configuration of the stem mould and closing the stem mould such that the first portion is securely held in place inside the stem mould in a closed configuration of the stem mould.

23. A method of manufacturing a dart flight stem according to any one of Claims 19 to 22, wherein the first portion includes two or more projections that are contacted by the stem mould in the closed configuration to hold the first portion in place.

24. A method of manufacturing a dart flight stem according to any one of Claims 19 to 23, wherein the stem mould secures the first portion on opposite sides of the first portion to inhibit lateral motion of the first portion during moulding of the second portion.29 01 2425. A method of manufacturing a dart flight stem according to Claim 24, wherein the stem mould includes clamp parts for securing the first portion on opposite sides, and wherein the clamp parts define windows in the sides of the moulded second portion.

26. A method of manufacturing a dart flight stem according to any one of Claim 24 or 25, wherein the lateral motion is inhibited in a direction substantially orthogonal to a direction in which a or the projections of the first portion project.

27. A method of manufacturing a dart flight stem according to any one of Claims 23 to 26, or Claim 23, wherein moulding the second portion includes substantially covering and surrounding the first portion with the second material injected into the stem mould, with the exception of the projections that are contacted by the mould, such that the projections are uncovered by the second material at least at their radially outer surfaces .

28. A method of manufacturing a dart flight stem according to any one of Claims 19 to 27, wherein the dart flight stem is a dart flight stem according to any one of Claims 1 to 18.

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