GB2530163A

GB2530163A - A tool for cutting a flue

Info

Publication number: GB2530163A
Application number: GB1513370.5A
Authority: GB
Inventors: Simon Brown
Original assignee: Individual
Current assignee: Individual
Priority date: 2014-07-29
Filing date: 2015-07-29
Publication date: 2016-03-16
Anticipated expiration: 2035-07-29
Also published as: GB201413392D0; GB2530163B; GB201513370D0

Abstract

A tool suitable for facilitating cutting a balanced flue, the flue comprising an outer pipe and an inner pipe. The tool provides a base which is adapted to engage a worktop , an outer pipe holder part supported on the base, and a cutting guide 3a which encourages a blade to cut around the circumference of either a pipe. The outer pipe holder allows keeps the outer pipe in position, while allowing it to be rotated around its central long axis. Preferably, the outer pipe element is formed of first and second elements 1, 2 which can be longitudinally adjusted with regard to one another. Preferably each pipe holder comprises a V-shaped structure. Preferably the cutting guide is provided by two rigid uprights, with one projecting from each side of the first element of the pipe holder. The cutting guide may comprise a cutting slot and may comprise an abutment to prevent a blade cutting into the inner pipe. The tool may comprise an inner pipe support 10 and may also comprise a deburring tool 15.

Description

A TOOL FOR CUTTING A FLUE

Technical Field

ooq The present invention is a tool for cutting a balanced flue to fit during installation. A balanced flue consists of an inner pipe through which combustion products are exhausted with a substantially concentric outer pipe through which air for combustion is inducted. When properly installed this ensures a sufficient supply of combustion air to achieve total combustion of the fuel (usually natural gas) and the safe exhaust of the combustion products from the building. Balanced flues are commonly constructed from thin gauge metal approximately 0.5 to 2mm thick, usually 1mm thick or less. The outside diameters of inner and outer pipes are nominally6omm innerwith 100mm outeror7omm innerwith 110mm outeralthough other sizes are or may become available. The inner pipe is not usually supported within the outer and must be cut longer than the outer by a minimum safe distance, usually 20mm, so that the inner can be received into a seal in a flue capon the external surface of the wall. This arrangement ensures that the exhaust does not mix with the inducted gasses or worse return into the building space where the fumes may injure occupants.

[002] Commonly the outer is fed through a seal ring attached to a hole cut through the wall to receive the flue. This prevents the unwanted passage of air through the wall hole.

[003] It is important that the circularity of the respective flue pipes is maintained, that the cut edges of the pipes are free of burrs to prevent damage to the aforementioned seals and ensure that the seals contact the whole periphery of the pipes.

Background Art

[004] The conventional way for a heating engineer to install a flue during the process of fitting a new boiler/furnace is to cut the flue using a hacksaw, angle grinder or pipe-cutter while resting the flue on a workbench. Many worksites provide little or no room for even a portable workbench, and workbenches will conventionally secure the flue only by means of a vice action which is liable to deform the flue and makes progressive rotation of the flue slow and inconvenient. It is often inconvenient to carry a workbench to the worksite. In consequence the heating engineer will frequently improvise using an available table or like surfaced furniture as a work surface and attempt to hold the round outer pipe while progressively rolling the flue as it is cut using a hacksaw. Considerable care must be taken to avoid deforming the outer pipe while cutting it squarely and not damaging the inner pipe. Because the inner pipe is not easily supported, subsequent cutting of the inner pipe is similarly fraught. There is also a significant risk of damaging the customer's furniture.

[005] Using an angle grinder to cut the outer and inner pipes does not greatly simplify the exercise and is often unacceptably hazardous due to the discharge of very hot swarf from the rotating blade. A pipe cutter able to cut 110mm diameter tube is unavoidably, inconveniently large and not generally capable of sufficient adjustment to cut 110mm, 100mm, 70mm and 60mm tube. Consequently such tools are rarely carried.

[006] There is perceived to be a requirement for a tool which is convenient to carry, being light and compact, able to facilitate the accurate cutting of a balanced flue of a range of sizes, robust and inexpensive. Preferably the tool will significantly reduce the time and effort required to cut a flue thereby enhancing the productivity of the engineer.

Statement of Invention

[007] Accordingly the present invention provides a flue cutting tool comprising: a base part adapted to engage a worktop and resist displacement, said base part supporting an outer pipe holder part which resists the outer pipe rolling while permitting the outer pipe to be rotated around its central long axis; a cutting guide to encourage a blade to cut around the circumference of either of the inner or outer pipe on a plane perpendicular to the pipe axis; and means to prevent or remove burrs forming or formed at the cut edge of the inner or outer pipe.

[008] The base part is preferably a flat surface which may be treated with a layer of slip resistant resilient high friction material to deter the base part from sliding when pressed against a flat work surface such as a wooden, melamine laminate, stone or ceramic surface. 3M and Heskins Ltd catalogues offer a range of suitable materials.

[009] The outer pipe holder part may advantageously be formed from first and second elements which can be brought together for compact storage and longitudinally separated in order to support a long flue. Each of the outer pipe holder elements may advantageously be integral with a base part so that the base part can be extended and compacted with the pipe holders for respective use or carriage and storage. Each pipe holder element preferably comprises a flat work surface engageable base part supporting a "V' notch pipe holder structure providing opposing pipe engaging surfaces in the form of a "V' or a truncated "V. The span between the opposing pipe engaging surfaces will range between the smallest size of outer pipe to be worked on and the largest size of pipe to be worked on, eg lOOmm-llOmm. The surfaces of each V will preferably have flat opposing surfaces treated with a slip resistant resilient material or otherwise provided with a surface finish which provides a resistance to the outer pipe rolling around its axis. The pipe holder elements thus provide a cradle for the outer pipe.

[0101 The cutting guide may be provided by two rigid uprights projecting up one from each side of the first element of the pipe holder parts. Each of the uprights extends away from the base part surface to a point above the surface of the largest outer pipe to be accommodated by the tool so that a hacksaw may contact each of the uprights and the outer pipe when cutting is initiated. So long as the blade is kept in contact with the cutting guide during the cutting operation the cut will be perpendicular (square) to the long axis of the flue and outer pipe. Some embodiments may include a guide with a cutting slot. The cutting guide may provide the slot between two longitudinally spaced members. Alternatively the cutting guide may provide a trap vertically displaceable along the cutting guide which permits only cutting movement of the blade perpendicular to the long axis of the flue and tool. The cutting guide may provide an abutment projecting forwards from the guide at a height to prevent the saw cutting into the inner pipe. Each abutment may be in the form of a roller free to roll around a trunnion so that the roller cannot easily be cut through by an inattentive worker. In some embodiments a blade is mounted in use on the uprights of the cutting guide, and travels along the uprights perpendicular to the pipe axis; for example wherein the uprights comprise two uprights and the blade is mounted there between on collars which provide a blade trap, so as to allow variation of angle between collars and thereby allow variation in the cutting angle of the blade. Where a trap type cutting guide is used the sliding movement may be limited to a point where the inner pipe cannot be accidentally cut.

[Oil] An inner pipe support may be provided in the form of a stepped ring which can be closely sleeved over the inner pipe and partially received into the annular air intake passage between the inner pipe and the outer pipe. The inner pipe support has a projection arranged to abut the outer pipe so that a correct length of uncut projecting inner pipe is enveloped by the inner pipe support. A projecting end of the inner pipe support is perpendicular to the axis of the inner pipe when emplaced for use and provides a cutting guide to facilitate a square cut of the inner pipe so that the cut inner pipe projects the required distance (commonly 20mm) from the outer pipe.

Thus when the user has cut the outer pipe to the required size, the inner pipe support is emplaced and provides a cutting guide to cut the inner pipe square and to the correct length. In some embodiments of the invention multiple inner pipe supports may be provided dimensioned to accommodate several different sizes of flue. However the applicant also envisages an inner pipe support having displaceable members such as ribs, or an iris action to adapt to several sizes of flue.

In the most simplified variant the inner pipe support may comprise an 0" ring for insertion into the piping in addition to or instead of the template. The "0" ring may be sufficiently deformable to accommodate the different flue sizes.

[0121 Cutting using a hacksaw blade will usually result in significant burring of the edge of the flue. To remove the burrs from each of the cut edges of the inner and outer pipes a deburring tool is provided. This is in the form of a ring having an axial facing abrasive surface. Preferably the deburring tool will have a shoulder around the outer periphery to closely internally receive the pipe being deburred and to provide a convenient manual gripping surface. Preferably the axial facing surface is frusto-conical to chamfer the cut edge as it is deburred.

[0131 Preferably each of the first and second elements and the culling guide are connected by a supporting frame along which at least one element can slide longitudinally to be deployed for use or compacted for carriage or storage. The frame may comprise one or more stiff elongate members, which may advantageously be tubular. Each of the aforementioned components may be attached to or adapted to be attachable to the frame for convenient carriage and storage. One or more members of the frame may be configured to provide a convenient carrying handle. In a preferred embodiment the carrying handle is detachable which facilitates securing the other components for storage or separation for use. In some preferred embodiments the elongate members of the frame may be extensible. For example a member may be telescopic or adapted to be formed by joining several elements together to form an elongated member for use and a compacted form for storage and carriage.

[014] In some variants of the invention the tool may be adapted to facilitate culling the outer and/or inner pipes using an angle grinder. In this case the culling guide may be provided by an arm extending from a pipe holding element and adapted to secure the handle of the angle grinder. Hook and loop straps or cam straps may serve to secure the handle of the angle grinder to the arm. The arm will be arranged to permit a limited pivoting movement of the angle grinder sufficient to cut into an arc of the outer pipe but not the inner pipe.

[015] The cutting guide and pipe holder elements may be formed from plastics, such as acrylonitrile butadiene styrene (abs) or polyethylene or similar robust synthetic plastics. Both the guide and holder have non-slip grip rubber base portions (not shown). In some embodiments inner contact faces (such as 14) are provided in felt or other soft touch material.

[016] The inner pipe support may be formed of a relatively robust or dense plastics such as polyethylene or acronytrile butadiene styrene, resistant to damage during cutting, ideally having deformable seals of rubber or similar to ensure effective fitment within the outer pipe.

[017] In some variants the tool includes a blade, for example a serrated blade, arranged to cut orthogonal to pipe axis and/or along or parallel to the guide.

[018] In some embodiments the pipe contact surfaces may be movable whereby the inner pipe may be supported by the contact face.

[019] In a variant of the tool the pipe engaging surfaces might be replaced by opposing rollers with the periphery of each roller engageable with the surface of the pipe.

Each roller would be braked to resist rotation or to rotate through an indexed angle when a sufficiently large torque is applied in order to progressively rotate the flue as the outer surface is cut. By indexing the rotation the tool can ensure that a minimum number of substantially horizontal cuts is required to remove a waste outer pipe.

Brief Description of Figures

[020] A tool for cutting a flue embodying the present invention will now be described, by way of example only, with reference to the accompanying illustrative drawings, in which: Figure 1 shows an isometric view of a first embodiment of the tool: Figure 2 shows an isometric view of the first embodiment of the tool in use to cut a flue; Figure 3 shows a right side elevation of the embodiment shown in Figure 1; Figure 4 shows an isometric exploded view of the embodiment shown in Figure 1 with a handle for attachment; Figure 5 shows an isometric view of the embodiment shown in Figure 1 packed with a deburring tool and handle; Figure 6 shows a view from above of the embodiment shown in Figure 1 with a handle; Figure 7 shows an isometric exploded view of the embodiment shown in Figure 5; Figures Ba is a plan view of the first embodiment packed for carriage or storage; Figure Sb is a side elevation of the first embodiment of the tool in the packed condition; and Figure 9a shows a photorealistic perspective view of a deburring tool, Figure Gb shows a sectional view of a template and template covering plate.

Figure 10 is a SE dimetric view of a second embodiment of the invention; and Figure 11 is an efflarged NW dimetric view of the second embodiment of the invention.

Detailed Description of the Embodiment

[021] The flue cutting tool has an outer pipe holder part comprising a first element 2 and a second element 1. In the use condition illustrated in figure 1 the first and second elements 1, 2 are spaced longitudinally along a pipe axis in preparation to receive an elongate flue ready for cutting. Each pipe holder element 1, 2 is formed from a rectangular section of metal tube pressed along the longitudinal pipe axis to form a V" shaped notch defined by opposing pipe engageable surfaces la and 2a. A support web ib, 2b, is formed to extend between the bottom of the V" notch and an underlying base web ic, 2c. The base webs ic and 2c are each covered on an outer surface with a slip resistant resilient material so that when placed on a work surface the pipe holder element and therefore the tool is resistant to sliding and unlikely to damage the surface. The pipe engageable surfaces la and 2a, may be similarly coated with slip resistant resilient material so that a pipe pressed against the surface is unlikely to slip longitudinally or to rotate about its long axis.

[022] Each holder element 1, 2 has a pair of parallel elongate circular sleeves id and 2d attached to upright side walls le and 2e. Each split sleeve id 2d provides a clip to slidably receives one of a pair of tubes 5. The frame formed by the tubes 5 maintains the longitudinal alignment of each holder element 1, 2. In the use condition shown in figure 1 the [023] To reduce the number of components and weight of the tool a single square section tube might be received into a complementary shaped sleeve formed on the axis of the tool beneath the outer pipe engaging webs la, 2a.

[024] The tool shown has two parallel horizontally spaced frame tubes 5 of fixed length.

However, the frame may be made extensible, either to result in a tool which can be made more compact or to accommodate longer flues. Extensibility may be achieved via: telescopic tubes, tubes in multiple sections which can be sleeved together or tubes formed from hinged sections which can fold or unfold.

[025] A cutting guide 3a comprises a metal panel extending across and attached to a front surface of the first pipe holding element 2. The cutting guide is profiled to correspond to the pipe engaging surfaces of the first pipe holding element 2 except that the lateral edges of the cutting guide project up to provide laterally spaced uprights 3 extending up sufficiently to extend above the highest point of an outer pipe with which the tool is designed for use as can be seen in Figure 3. Thus the cutting guide provides a guide for a blade to make a cut in the outer pipe perpendicular to the outer pipe axis. In some variants the first pipe holder 2 and uprights 3 are a single piece (unitary). In some variants the cutting guide may be formed to have two longitudinally spaced uprights on each side of the pipe receiving space to form a slot to receive a cutting blade. The blade is typically an independently provided hacksaw.

[026] To further protect the work-surface from swaif formed by cutting the flue, the panel forming the cutting guide is bent horizontally and forwardly at the base of the pipe holder element 2 to provide a baseplate 4. In some further variants the base plate may be stowable for example hinged or slidable.

[027] The holder maintains a length of pipe substantially horizontally when used on a horizontal surface, wherein the holder is extendable to accommodate different lengths of piping. The holder and guide provide parallel surfaces for or adjacent to two ends of a length of piping, in order that the blade is enabled to effectively and repeatedly make a cut perpendicular to an axis defined by the holder and guide.

[028] The tool further comprises at least one inner pipe support 10. The inner pipe 10 support is best illustrated in figure 7 and comprises a short tube ba having a guage corresponding to the distance between the inner pipe and the outer pipe of the flue.

Thus for a flue having an inner pipe of 60mm and an outer pipe of 100mm and a

S

gauge of 1mm the inside bore of the inner pipe support will be of 60mm diameter and the outside diameter will be 98mm. A flange lOb extends medially around the tube ba and has an external diameter of slightly more than 100mm to abut the cut end of the outer pipe. The length of one side of the tube 1 Oa extending from the flange lOb will be at least 10mm and more usually 20mm to serve as a cutting guide for the inner pipe. Arcuate notches bc are formed into the periphery of the flange lOb at diametrically opposite points to receive the respective frame tubes 5 when the inner pipe support is slid between the frame tubes for storage as shown in figures Ba and Bb.

[0291 In use the inner pipe support 10 is sleeved over the projecting uncut inner pipe and the tube bOa received into the outer pipe. Thus the inner pipe is supported concentrically against the outer pipe and the tube lOa projects from the flange lOb by a required offset cutting distance. A second inner pipe support 10' is provided dimensioned for cutting a flue with a 70mm inner pipe and a 110 mm outer pipe.

Further inner pipe holders may be provided for other flue sizes.

[030] In the pictured embodiment the inner pipe holder 10 serves both the purpose of supporting the inner pipe against the outer pipe and as an offset cutting guide.

However, in some variants the inner pipe support and the inner pipe cutting guide may be divided into two components.

[031] It is also possible to provide an adaptive inner pipe support to accommodate two or more flue sizes by providing movable elements which change the effective inner and outer diameter of the tube. Or by the use of removable adaptor rings. The inner pipe support 10 may conveniently be moulded from plastics to minimise cost and weight. In order to protect the front surface of the tube 1 Oa from wear during cutting a metal ring 9 may be provided to sleeve over the inner pipe of the flue after the inner pipe support 10. In the embodiment shown two metal inner pipe cutting rings 9, 9' are provided of sizes to accommodate the different sizes of flue inner pipe. The inner pipe supports and plate in the picture embodiment contain through holes 11 for threading onto the frame tubes 5. Each of the pipe cutting rings 9, 9' is formed with diametrically opposed circular notches in the outer periphery of the ring into which locate the respective frame tubes 5.

[032] Cutting with a hacksaw tends to produce burrs on the cut edge which need to be removed for safe and reliable installation of the flue. Accordingly the tool includes a deburring tool 15. The deburring tool 15 comprises an outermost first ring isa, presenting an inner surface 15b at a diameter corresponding to the largest size of flue outer pipe (normally 110mm). The first inner surface 15b. The first ring 15a supports a second ring 15c of lesser diameter and presenting a second inner surface 15d with a diameter corresponding to the smaller outer pipe size (100mm).

A third ring 15e is supported by the second ring 15c and presents a fourth inner surface 15f corresponding in diameter to the diameter of the largest inner pipe size (70mm). A fourth innermost ring (not shown) is supported by the third inner ring and presents an inner face corresponding in diameter to the smallest inner pipe diameter (60mm). Each of the inner faces and end faces is stepped and treated to be abrasive so that pressing a pipe such as 70mm inner pipe "P" into the correspondingly sized ring and rotating the ring against the pipe will remove any burrs present. Abrasion treatment may include bonding layers of emery paper to the surface. The axially extending inner surfaces may be slightly conical to chamfer the cut end of the pipe.

[033] The deburring tool 15 includes through holes 15g corresponding to the frame tubes 5.

[034] The tool will ordinarily be stored and carlied in a compacted form as shown in figures 5, 8a and 8b. In this compacted form the second pipe holder element 1 has been slid along the frame tubes 5 to abut a rear face of the first pipe holder element 2. Each of the rings 9, 9' inner pipe supports 10, 10' and the deburring tool 15 are mounted sequentially onto the frame tube and retained by a handle 6.

[035] The handle 6 is provided by a U" shaped tube and attaches to the ends of the frame tubes 5 by means of a female socket 8 provided on the handle into which an end of a frame tube is received. The end of the frame tube is retained by spring nubs 12 projecting through accommodating holes in the ends of the frame tubes 5 to be received into corresponding holes in the socket 8. The handle is covered with a foam grip 13.

[036] Referring to the second embodiment shown in figures 10 and 11 a flue F having an outer pipe 0 and an inner pipe I is shown in place on the second embodiment of the tool with a rear portion of the flue partially cut away for the purpose of illustration only. The second embodiment exhibits a cutting guide having 3a formed with panels bent to extend parallel to the long axis of the tool in order to provide a slot 3b to guide a saw blade S. The vertically extending slot 3b terminates in a roller 3c at a location which ensures that the blade cannot cut the inner pipe I. In some variants the position of the roller in the slot can be adjusted to any one of two or three positions to be compatible with different sized flues (60/100 or 70/110).

[037J As can best be understood from figure lithe pipe holding elements 101, 102 are essentially identical so that only the second pipe holding element 101 will be described. The pipe holding element 101 comprises a chassis 103 having a base 104 adapted to rest on a flat work-surface such as a table. A slip resistant resilient tape 105 is applied to the base 104. The chassis 103 may be cast from metals or preferably injection moulded from plastics. The chassis 103 has upstanding inclined side walls 106R and 106L and vertical front and rear end walls 107F and 107 R which rise to support respective left and right top panels 108R, 108L.

[038J Formed into each top panel is a centrally located roller well 109 which extends into a forward and backward axle support well 110. The each axle support well has a wide uppermost portion 111 and a narrow lower portion 112. A bearing support 113 is slidably received into the narrow lower portion 112 and urged upwards by a bias spring 114. A roller 115 is received into the roller well 109 and supported irrotatably on a polygonal section axle 116 bearing against the bearing support 113 so that when lightly loaded, as shown, the roller projects a maximum height above the top panel. In use a shown in figure 9 the spring force of spring 114 is sufficient to raise the axles 116 into the widened region of the axle well so that they can readily rotate and enable the flue to be manually rotated to its next cutting angle. The user then presses down on the flue F both with one hand and the force of the blade S. This overcomes the spring force and displaces the polygonal axle 116 into the narrow lower portion 112 where its polygonal shape engages with the side walls of the lower portion to prevent rotation. The high friction engagement between the rollers 115 and the flue therefore prevent the flue from rotating during the cutting process. The grip of the rollers may be enhanced by covering with an appropriate resilient slip resistant material. By appropriate design of the polygonal axle shape the user is encouraged to use the minimum number of cutting angles required to complete the separation of the waste flue pipe.

[039] A further difference between the first and second embodiment is the use of a single square section frame member 117, which is longitudinally, but not rotatably slidably received into a complementarily shaped hole 118 formed in each pipe holding element. A handle 119 may be formed as shown in figure 10.

[040] The features of either embodiment are, with adaptations within the scope of the skilled person interchangeable. For example, the pipe holding element of the second embodiment using rollers, may be used in conjunction with a pipe holding element 2 of the first embodiment and mounted on frame consisting of two or more circular section tubular members 5 or a single non-circular section tubular member.

[041] The process of using either tool is similar in that, starting from the compacted state the handle is removed, the inner pipe support(s) 10 and deburring tool is removed and the pipe holding elements 1 and 2 separated longitudinally on the frame and rested on a general purpose work surface. A flue to be trimmed for fitting is placed on to the pipe support elements with the measured waste for the outer pipe projecting through the cutting guide. A conventional hacksaw can then be used to cut along the cutting guide to make a first segmental cut. The flue is then rotated approximately 50 to 60 degrees without longitudinal displacement and a further segmental cut made. This process is repeated until the waste outer pipe is completely separated and removed.

[042] The inner pipe support 10 is then sleeved over the inner pipe until the tube part is received into the remaining outer pipe and the flange abuts the cut edge of the outer pipe. The projecting part of the tube provides a cutting guide against which the saw can be pressed to cut squarely through the inner pipe.

[0431 With the waste inner pipe removed and the inner pipe support, the deburring tool is applied to the cut edges of the inner and outer pipe and rotated to remove burrs and chamfer the cut edges of the inner and outer pipe.

Claims

Claims 1. A flue cutting tool comprising: a base part adapted to engage a worktop and resist displacement, said base part supporting an outer pipe holder part which resists the outer pipe rolling while permitting the outer pipe to be rotated around its central long axis; a cutting guide to encourage a blade to cut around the circumference of either of the inner or outer pipe on a plane perpendicular to the pipe axis.
2. A tool according to claim 1 wherein the base part is a fiat surface treated with a layer of slip resistant resilient high friction material.
3. A tool wherein the outer pipe holder part may advantageously be formed from first and second elements which can be brought together for compact storage and longitudinally separated in order to support a long flue.
4. A tool according to one of claims ito 3 wherein each of the outer pipe holder elements is integral with a base part so that the base part can be extended and compacted with the pipe holders for respective use or carriage and storage.
5. A tool according to any one of the preceding claims wherein each pipe holder element comprises a flat work surface engageable base part supporting a V' notch pipe holder structure providing opposing pipe engaging surfaces in the form of a V" or a truncated "V'.
6. A tool according to any one of the preceding claims wherein the cutting guide is provided by two rigid uprights projecting up one from each side of the first element of the pipe holder parts.
7. A tool according to any one of the preceding claims having a cutting guide with a cutting slot.
8. A tool according to any one of the preceding claims wherein the cutting guide provides an abutment projecting from the guide at a height and in a direction to prevent a blade cutting into the inner pipe.
9. A tool according to claim 8 wherein the in abutment is in the form of a roller free to roll around a trunnion.
10. A tool according to any one of the preceding claims wherein the cutting guide comprises a trap which is slidable vertically and traps the blade to move in a plane perpendicular to the long axis of the tool and the flue.
11. A tool according to claim 12 wherein the sliding movement is limited to a point where the inner pipe cannot be accidentally cut.
12. A tool according to any one of the preceding claims having an inner pipe support to span the gap between the inner and outer pipe and thereby support the inner pipe.
13. A tool according to claim 13 wherein the inner pipe support is in the form of a tube sized to sleeve over the inner pipe and having an outside diameter with a sliding fit into the outer pipe.
14. A tool according to claim 13 wherein the tube is surrounded by a flange sized to abut the cut end of the outer pipe when the tube is received into the outer pipe
15. A tool according to claim 14 wherein the flange is located so that the tube projects forward of the flange and has a projecting end face to provide a cutting guide perpendicular to the long axis of the inner pipe.
16. A tool according to claim 14 wherein the inner pipe support cutting guide extends forwardly of the flange a distance sufficient ensure the inner pipe offset cut is correct.
17. A tool according to anyone of the preceding claims including a deburring tool.
18. A tool according to any one of the preceding claims wherein the deburring tool is a tube of multiple stepped diameters corresponding to the standard diameters of the outer and inner pipes of a flue, and the axially facing surfaces of each step are treated to be abrasive.
19. A tool according to any one of the preceding claims having a frame to support the pipe holding elements and the cutting guide with the pipe holding elements longitudinally spaced for use and compacted together for portability and storage.
20. A tool according to claim 19 wherein each of the inner pipe support and the deburring tool are adapted to be stored on the frame.
21. A tool according to claim 20 wherein the frame consists of two parallel horizontally spaced circular tubular members.
22. A tool according to any one of claims 19 to 20 wherein the frame consists of a single non-circular section tubular member.
23. A tool according to claim 1 wherein at least one pipe holding element comprises rollers disposed to engage the pipe surface having a rolling axis parallel to the long axis.
24. A tool according to claim 23 wherein the rollers are arranged to roll freely when lightly loaded by the weight of the flue but resist rotation when the flue is pressed down in order to resist rotation of the flue.
25. A tool as herein described with reference to the accompanying figures.