GB2231517A - Sharpening sawblades - Google Patents

Abstract

Apparatus for sharpening a circular saw comprises amount (26) for a circular sawblade (1), a grinding wheel (23) or the like, and a pivotably adjustable table (20) to retain the mount and the wheel in at least two alternate relative positions spaced angularly about an axis (22) in, or in close parallel relation to, the radial face of the grinding wheel (23) so that alternate teeth of the sawblade can be brought into contact with the grinding wheel in different angular orientations. A second mount (27) on the table (20) supports the sawblade (1) for grinding another tooth surface. The sawblade teeth may be reset by supporting the blade on a platform having an inclined edge and hammering each tooth to conform to the inclined edge. <IMAGE>

Description

IMPROVEMENTS IN OR RELATING TO

SHARPENING This invention relates to sawblade sharpening, particularly to an arrangement intended for use in sharpening a circular sawblade.

At present, when a circular sawniade becomes blunt, it must be sharpened or discarded. In sharpening the sawblade faces, each of the teeth must be ground at specific angles to the plane defined by the main part or bod- of the circular sawblade. This usually requires consicnerable skill, and thus the task of sharpening a circular sawblade cannot in general be carried out by the ordinary user of a circular saw and is usually left to a specialist in the sharpening field.

It is accordingly desirable to provide n apparatus which will facilitate the sharpening cf a circular sawblade and enable such sharpening to be performed by the D.I.Y.

enthusiast.

According to one aspect of this invention there is provided an apparatus for sharpening a circular sawblade, said device comprising a mount upon which a circular sawblade may be mounted, a grinding wheel or the like, adjustable means to retain the mount and the wheel in at least two alternate relative positions, such that when a circular sawblade is mounted on the mount in one position a face of a tooth of te sawblade can be brought into contact with the grinding wheel in one desired angular orientatlcn and in the other position the corresponding face of ancher tooth of the sawblade may be brought into contact wi the grinding wheel at another desired angular orientation.

Preferably said means comprises pivotably adjustable means to retain the mount and the wheel in at least two alternate relative positions spaced angularly about an axis in, or in close parallel relation to, the radial face of the grinding wheel.

Preferably the said two alternate relative positions are such that in one condition the said face of the tooth of the sawblade will be ground at one angular orientation relative to the plane of the blade of the saw (i.e. the body of the sawblade), whereas in the other relative position the corresponding face of another tooth will be ground at an opposite angular orientation relative to the plane of the blade of the saw.

Conveniently the two opposite angular orientations of the face to the plane are equal to one another, preferably at to the perpendicular to the plane.

Advantageously the mount may be retained in three alternative relative positons. In one positon the angular orientation of the face may be perpendicular to the plane.

Preferably the device incorporates a further mount, also adapted to be retained in the said alternate relative positions in one of which, when a circular sawblade is mounted thereon, another face of a tooth of the sawblade can be brought into contact with the grinding wheel in one desired angular orientation, and in the or one other position of which the corresponding face of another tooth may be brought into contact with the grinding wheel at another desired angular orientation.

Advantageously the or each mount is adjustably positionable.

Preferably each mount is movable linearly.

Conveniently the device incorporates a table, the or each mount comprising a shaft protruding above the table, but being movable axially along an elongate slot formed in the table, means being provided to secure the mount in position.

Preferably the means to secure the mount in position comprises a plate located on the underside of the table, the shaft being mounted on the plate and the plate having an elongate aperture therein, a stud from the table passing through the elongate slot, there being locking means on the stud to lock the plate in position.

Preferably the shaft is mounted for movement relative to said plate, axially of said slot in the table.

Advantageously a guide pin is provided associated with the or each mount, the guide pin being adapted to engage part of the sawblade when mounted upon the mount to retain the sawblade in a desired position.

Preferably the guide pin or at least one of the guide pins is adjustably mounted in positon.

Conveniently the said guide pin or at least one of the guide pins is mounted on a plate which extends under the table, a stud from the table passing through an elongate slot formed in the plate, there being a lock means co-operating with the stud.

Advantageously the or each mount is supported on a support which is pivotally connected to a base.

Preferably, releasable locating means (e.g. clamp means) are provided for an electic drill to drive the grinding wheel, e.g. by clamping the grinding wheel's arbor into the drill's chuck.

Alternatively a permanently attached motor may be provided to drive the grinding wheel.

Preferably the device is provided with a mounting block to enable the device to be mounted in a vice.

According to another aspect of this invention, there is provided apparatus for sharpening a circular sawblade, comprising a grinding wheel or the like, and support means having first and second locations for a sawblade mount which, when in the said first location, enables a sawblade thereon tb be moved in a first direction with respect to the grinding wheel and when in the said second location enables a sawblade thereon to be moved in a second direction with respect to the grinding wheel.

Preferably said first and second directions are substantially at right angles to one another. Conveniently, when the support means supports the sawblade in a plane containing the axis of the grinding wheel, said first direction is substantially parallel to the axis of the grinding wheel and said second direction is substantially parallel to the radial face of the grinding wheel.

Advantageously the spacing between the radial face of the grinding wheel and the path of movement of the sawblade when on the mount in its said second location can be adjusted between first and second values. This enables different kinds of sawblades to have the leading edges of their teeth sharpened by the apparatus.

Preferably the said support means is positionally adjustable to incline a sawblade on said support means to the plane containing the axis of the grinding wheel (or to a plane closely parallel thereto). The angle of inclination is preferably of the order of 50 Advantageously the said support means is positionally adjustable such as to be inclined selectively to each side of the said plane.

According to another aspect of this invention, there is provided a device for setting a circular sawblade, said device comprising a platform, a mount for a sawblade mounted on the platform, the platform having an inclined edge at an angle of inclination corresponding to the intended angular "set" of the sawblade.

Preferably the mount is adjustably positioned on the platform.

Preferably the mount comprises a shaft extending above the platform, a threaded stud passing from the shaft through an elongate aperture in the platform to a lock nut located under the platform, so that the shaft may be selectively positioned.

Conveniently the platform is provided with a depending boss, the boss having opposed flat faces to enable the boss to be mounted in a vice.

The sawblade sharpening device may be provided in conjunction with the sawblade setting device.

In order that the invention may be more readily understood, and so that further features thereof may be appreciated, one exemplary embodiment of the invention will now be described with reference to the accompanying drawings of which: FIGURE 1 is a plan view of part of the periphery of a circular saw, FIGURE 2 is a sectional view taken on the line II-II of Figure 1, FIGURE 3 is a sectional view taken on the line III-III of Figure 1, FIGURE 4 is a sectional view taken on the line IV-IV of Figure 1, FIGURE 5 is a sectional view taken on the line V-V of Figure 1, FIGURE 6 is a view corresponding to Figure 2, but illustrating a sectional view through a tooth of a rip saw blade, FIGURE 7 is a view corresponding to Figure 4, but illustrating a sectional view through another tooth of the same rip saw blade, FIGURE 8 is a perspective view of a sawblade sharpening apparatus in accordance with the invention, FIGURE 9 is a side view of the apparatus of Figure 8, FIGURE 10 is a view of part of the apparatus illustrated in Figure 9, FIGURE 11 is a perspective view of a component for use with the apparatus of Figures 8 to 10, FIGURE 12 is a sectional view illustrating part of the component of Figure 11, in use, FIGURE 13 is a top plan diagrammatic view of parts of the apparatus illustratina one operation during sharpening of a sawblade, FIGURE 14 is another diagrammatic vieu of parts of the apparatus illustrating another operation during sharpening of a sawblade, FIGURE 15 is a top perspective view of a device according to another aspect of this invention and for use in setting the teeth inclinations of a sawblade, and FIGURE 16 is an underneath perspective view of the device shown in Figure 15.

Referring initially to Figures 1 to 5 a circular sawblade 1, which is a cross-cut or combination sawblade, consists of a planar disc 2 which defines a single plane, having a plurality of peripheral teeth 3,4,5,6.. .2N. In a circular sawblade the total number of teeth is always an even number.

Adjacent teeth are deflected out of the plane of the plate 2 in different senses. The teeth may be considered to be "odd" numbered teeth, such as the teeth referenced red 3,5 and "even" numbered teeth, such as the teeth referenced 4,6.

As can be seen from Figure 2, which is a sectional view in a radial sense of an "odd" tooth, the tooth 3 has the tip 7 thereof deflected out of the plane of the plate in a right-handed sense, and it can also be seen that the outer face 8 of the tooth is not perpendicular to the plane of the plate, but is inclined at an angle of approximately 50 to the perpendicular, in a left-handed sense as shown.

Conversely, as can be seen from Figure 3, an "even" tooth, such as the tooth 4 has the tip 9 thereof deflected to the left, and has the outer face 10 thereof inclined in a righthanded sense.

Figure 4 is a sectional view in a tangential sense through the leading edge of a "odd" tooth. It can be seen that the leading edge 11 of the tooth does not extend perpendicularly to the plane of the disc 2, but instead is inclined at an angle of approximately 50 to the perpendicular, in a righthand sense.

It is appreciated that for proper sharpening of a cross-cut saw blade the outer faces of each of the teeth, that is to say the faces 8 and 10 must be ground, and also the leading edges of each of the teeth, that is to say the leading edges 11 and 12 must be ground. Ideally the faces must be ground to be substantially flat and have the appropriate angle relative to the plane of the main part of the sawblade.

The description given above relates to a cross-cut or combination saw. Another type of saw, known as a rip saw, does not have inclined outer faces to the teeth, such as the faces 8 and 10, but instead has transverse outer faces.

Figures 6 and 7, which correspond with Figures 2 and 3, show two teeth 13,14 on such a rip saw and illustrate the transverse outer faces 15, 16 of the teeth.

Referring now to Figures 8 to 10 of the drawings, an apparatus for use in sharpening a circular sawblade comprises a base 16 of planar form. The base may be fixed on a support surface, or may carry a block 17 on its undersurface to enable the base to be mounted in a vice. At one edge of the base is an upstanding support 18, and spaced inwardly therefrom is a pair of spaced upstanding supports 19, having bosses provided at their upper ends. A table 20, which is generally planar, is provided with a pair of upstanding lugs 21 disposed between the two spaced-apart bosses of the supports 19.

Pivot pins 22 extend through adjacent boss-and-lug pairings 19,21 so that the table can pivot about the axis defined by the pivot pins 22. A grinding wheel 23 is mounted to rotate in a plane transverse to (and substantially perpendicular to) the plane of the table 20, the saic. common axis of the pivot pins 22 lying substantially in (or in close parallel relation to) the radial face of the grinding wheel 13 at a position in which it intersects at right angles the axis of the grinding wheel 23 (or is closely adjacent to such a position). The grinding wheel 23 may be coupled to an appropriate fixed drive motor or, as preferred and illustrated, the grinding wheel's axle can be coupled to the chuck of an electric drill 25, that is releasably mounted on the support 18 by a clamping arrangement 24.

The table 20 is provided with two mounts 26,27 each adapted to receive a circular sawblade. With a circular sawblade on either of the mounts the common axis of the pivot pins 22 lies substantially in the plane of the sawblade.

The mounts are each of the same general design and are adjustable, in that they can be moved, firstly to accommodate saw blades of different size, and secondly to facilitate the sharpening operation.

The mount 26 consists of an upstanding shaft 28 having an enlarged collar 29, (e.g. provided by a circlip) towards the base thereof. Part of the shaft extends beyond the collar 29 and through an elongate slot 30 formed within the table 20. The bottom of the shaft is mounted to slide along a first elongate aperture formed in a flat plate 31 which is located beneath the table 20. The plate is provided with a downwardly turned lip 32 to enable the plate to be grasped and permit the plate's movement co-planar with and beneath the table 20. Thus the position of the plate can be adjusted, sliding the shaft 28 along the slot 30. A lock nut 33 is provided which can be used to lock the plate 31 in position.The lock nut is mounted on a threaded stud (not shown) which is secured to and extends beneath the table 20, the stud passing through a second elongate aperture in plate 31 which is parallel to, but longer than, the first elongate aperture. By releasing the lock nut 33 the plate can slide, with the threaded stud moving relatively along the second elongate aperture. By tightening the lock nut 33 the plate 31 can be locked in position. When the plate 31 has been locked in position, the shaft 28 may still be moved relative to the elongate slot 30, but the degree of movement is restricted by the length of the first elongate aperture in the plate 31, that is to say the aperture engaged by the bottom of the shaft 28.

With the lock nut 33 the plate 31 can be located in a desired position, selected having regard to the diameter of a circular saw blade. The circular sawblade can then be mounted on the mount 26, by passing the shaft 28 through the aperture in the centre of the blade. If the shaft 28 is smaller than the blade's aperture, a removable tubular boss (not shown) may have to be mounted on the shaft 28 to adapt the shaft's size to fit the diameter of the sawblade's central aperture.

The mount 27 is of a corresponding design, being associated with an elongate slot 34 in the table 20. The mount 27 is associated with a plate corresponding tc the plate 31.

It is to be noted that the slot 30 extends parallel with the axis of rotation of the grinding wheel 23, but is spaced from the axis. Similarly the slot 34 is parallel with the plane in which the grinding wheel 23 rotates, but is spaced from that plane.

As seen in Figures 8 and 9, a guide pin 35 projects upwardly above the plane of the table 20, adjacent the grinding wheel 23. The guide pin 35 is mounted on a plate 36 which is located underneath the table 20, the glide pin 35 extending up to project above the table through a recess 37 provided for that purpose. The plate 36 is provided with a downwardly-turned tab 37 to facilitate adjustable positioning of the plate, (and of the guide pin 35 thereon), and is also provided with a lock nut 38 co-operating with a threaded stud projecting beneath and secured to the table 20, the threaded stud passing through an elongate slot formed in the plate 36. Thus the guide pin 35 may be selectively positioned. The guide pin 35 is located adjacent the front radial face of the grinding disc 23, towards the peripheral edge thereof.A corresponding guide pin 39 is provided in a similar positionably-adjustable manner adjacent the other side of the grinding wheel, this guide pin 39 being behind the plane of the wheel's radial face and slightly beyond the periphery of the wheel.

As has been mentioned, the entire table 20 may be pivoted about the pivot pins 22. The pivot axis defined by the pivot pins 22 substantially intersects the axis defined by the drive shaft for the grinding wheel 23, as can be seen from Figures 8 and 9. The table 20 can be pivoted as indicated by the arrow 40 in Figure 9 between two terminal positions. Means are provided to lock the table in those terminal positions, and also in an intermediate position.

These locking means comprise a downwardly extending lug 41 provided on the table 20 which cooperates with an upwardly extending lug 42 provided on the base 16. The lug 42, as can be seen in Figure 10 is provided with three vertically spaced-apart apertures 43,44,45 therein whereas the lug 41 is provided with a single aperture 46. If the aperture 46 is aligned with the aperture 45 a bolt may be passed through the aligned apertures thus locking the table in position.

When the table is in this position it is inclined at an angle of 5 , in a right-handed sense (the upper phantom-line shown in Fig. 9). If the aperture 46 is aligned with the aperture 44 and a bolt is passed through the aligned apertures the table 20 is horizontal (the full line position shown in Fig. 9), whereas if the aperture 46 is aligned with the aperture 43 and a bolt is passed therethrough, then the table 20 is inclined at an angle of 50 in the left-handed sense (the lower phantom-line position shown in Fig. 9). In a modification, the holes 43-45 can be "coalesced" into a single arcuate slot (shown in Fig. 9).

A disc 47, shown in Figure 11, having a diameter just less than that of the sawblade 2, may be mounted on the respective mount 26,27 before the sawblade is mounted on the mount (see Figure 12). The teeth 3,4 of the sawblade 2 thus project beyond the disc 47, but the disc 47 keeps the teeth elevated above the table 20.

As has been mentioned above, in order to sharpen a circular cross-cut or combination sawblade properly it is necessary to sharpen the leading edge of each tooth and the outer face of each tooth. The following explains how this may be achieved for a cross-cut circular sawblade with the illustrated apparatus.

Initially the table is moved to the lowered position, and the circular sawblade 2 to be sharpened is mounted on the mount 27, the latter being positioned in the slot 34 so that the leading edge of each tooth can be aligned with the front radial face of grinding wheel 23, as shown in Figure 13.

The mount 27 is slid linearly in slot 31 to bring tooth 3 towards the peripheral edge of the grinding wheel 23 and is also turned somewhat arcuately so that the leading edge 11 of the tooth 3 comes into contact with the grinding wheel.

In so doing the leading edge of the next tooth comes into contact with the guidepin 39, the latter having been previously moved into a suitable position (and locked therein) to achieve such contact. Thus in this operation the sawblade is moved in the direction indicated by the arrow 48 substantially parallel to the radial face of the grinding wheel 23. In this manner upon rotating the grinding wheel 23, the leading edge 11 of the tooth 3 is ground to have the desired form. This procedure is repeated for alternate teeth until all the "odd" numbered teeth have had their leading edge sharpened. Thereafter the table 20 is raised so it is inclined towards the right, and the procedure is then repeated for all the "even" numbered teeth.

Having thus sharpened the leading edges of all the "even" and all the "odd" teeth, the sawblade 2 is removed from mount 27 and then located on the mount 26, as can be seen in Figure 14. The table is still in the raised position. The mount 26 is located at a convenient position in the slot 30 and the lock nut 33 is tightened. However the mount 26 can still move, axially of the slot 30 by virtue of the elongate aperture in the now fixed plate 3 in which the shaft 28 is mounted. With the leading edge 11 of an "odd" tooth 3 engaged with the guide 35, the entire blade 2 may be moved towards the grinding wheel 23 (in a direction parallel to the wheel's axis) by sliding the mount 26 along the slot 30, the shaft 28 of mount 26 sliding along the second elongate aperture in the plate 31.The outer face 8 of the tooth 3 will thus be brought into contact with the grinding wheel's radial front face and will be ground at the desired angle.

Subsequently the mount 26 is moved generally linearly away from the grinding wheel, is turned arcuately, and is then returned generally linearly towards the grinding wheel to bring the leading edge 11 of the next "odd" tooth 5 into contact with the stop 35 so that the outer face of this "odd" tooth S may then be ground. This procedure is repeated until the outer face of all the "odd" teeth have been sharpened. Thereafter the inclination of the table 20 is again adjusted so that instead of being in the raised position (at an angle of 50) the table is lowered to be inclined (to the left) at an angle of 50 The above- described sharpening procedure on mount 26 is then repeated for the outer face of all the "even" numbered teeth. Thus ultimately the outer face of each tooth 3,4,5,6...2N is ground to have the desired angular inclination.

For sharpening a rip saw having teeth as illustrated in Figures 6 and 7, the table 20 is moved to and maintained in the intermediate or horizontal position (in which apertures 44 and 46 are held aligned) and the rip saw is mounted on the mount 27.

The distance between the leading edge of a tooth and a diametral line parallel thereto, when measured at right angles to the diametral line and the leading edge is less for a rip saw than for a cross-cut or combination sawblade.

Accordingly to enable the leading edge of all the rip saw's teeth to be ground to the desired angle, the distance between the radial abrading face of the grinding wheel 23 and the centre line of the elongate slot 34 is reduced to suit. Such distance reduction may be readily effected by moving the grinding wheel 23 axially in a direction away from slot 30. This can be accomplished, for example, by providing the wheel's axle with two axially spaced circumferential grooves that receive selectively a transverse key of rod-shaped form extending through the wall of the axle housing and engaging in one or other of the axle's circumferential grooves.

Alternatively the elongate slot 34 and sawblade mount 27 may be provided in a planar sub-frame that is slidable (in a direction normal to the slot's centre line) between two positions, in a cut-out in the table 20 to vary the distance between the radial abrading face of the grinding wheel 23 and the centre line of the elongate slot 34. Conveniently in such an arrangement, the same planar sub-frame may be selectively positioned in another table cut-out such that its slot 34 and sawblade mount 27 can also serve as and for the illustrated slot 30 and mount 26 uszd for sharpening the outer face of each tooth of a cross-cut or combination sawblade as described above.

Although in the above-described embodiments of this invention the table 20 is tilted relative to the grinding wheel 23, it would be possible, in a modified embodiment, to tilt the grinding wheel relative to the table.

It happens from time to time, that the blades (be they of a rip saw or a cross-cut saw) become "unset". That is to say the teeth of the sawblade are no longer inclined to the left and right as illustrated in Figures 2,3, and Figures 6,7. A device 51 which can be used to re-set the inclination of the teeth of a circular sawblade is illustrated in Figures 15,16.

The device 51 consists of a platform 52 formed from an appropriate metal, which is of generally planar form, having a downwardly inclined leading edge 53. The platform may be provided with a rigid boss 54 having opposed flat faces 55 adjacent the base thereof to enable the platform to be mounted in a vice or the like. Mounted on the platform is a support 56 for a circular saw blade which is movable along an axially extending slot 57 and which can be secured tightly in position by means of a wing nut 58 beneath the platform 52. A circular sawblade may be mounted on the mount 56 and the position of the mount 56 may be adjusted, by means of the wing nut 58, so that a blade of the circular sawblade is lying adjacent the inclined edge 53 of the platform 52.A cross-paned hammer may ten be used to hammer the tooth of the sawblade until it lies flush with the inclined edge 53 of the platform 52, and is thereby set to the desired inclination. The sawblade may then be rotated so that the next-but-one tooth is in position adjacent the inclined ramp or edge 53 and if necessary the hammering procedure may then be repeated. This sequence of procedural steps is repeated until the complete circumference of the saw blade has been dealt with. The sawblade is then removed from off the mount 56, inverted and is replaced upon the mount 56 so as to permit setting of the remaining intermediate teeth in a corresponding way. All the teeth of the sawblade are thus set to have the desired inclination to the plane of the saw blades central body position.

This setting procedure may be performed before the blade is sharpened using the sharpening arrangement illustrated in Figures 8 to 12, or may be effected after sharpening the leading edge of all the teeth (the preliminary sharpening step, described above with reference to Figure 13), and before sharpening the outer face of cross-cut blades (the second sharpening step described with reference to Figure 14).

It will be appreciated that the device 51 can be utilised in conjunction with, and/or have some elements thereof provided by, parts of the sharpening arrangement shown in Figs 8 to 12.

If the teeth on a circular sawblade are kept well sharpened, only à small amount of "set1, is required. A sawblade with sharp teeth and a little set is better than a sawblade with teeth that are not so sharp, but widely set.

It will be appreciated that various modifications may be made to the illustrated embodiment of the invention without departing from its intended scope. For example, the guide pin 35 may be fixed instead of adjustable. Additionally or alternatively the sawblade support means provided by table 20 may be tilted, e.g. through EO to only one side of the horizontal. In use, once the "odd" eeth (say) have been sharpened (with the table at this inclination) the blade is removed and inverted to permit the "ven" teeth to be sharpened (with the table at the same inclination).

It will be apparent that by providing for pivotable adjustment of the means (such as table 20) which retain the sawblade mount (26 or 27), the angle of sharpening can be readily adjusted, if this is desired. Moreover, the provision of two mounts (or locations therefor) in the one table 20 of the illustrated embodiment, greatly facilitates sharpening of both the leading edge and the outer edge of each tooth of a cross-cut or combination sawblade (and also enables the leading edge of the teeth of a circular rip saw blade to be readily sharpened therewith).

Claims (33)

1. Apparatus for sharpening a circular saw, said apparatus comprising a mount upon which a circular saw blade may be mounted, a grinding wheel or the like, and pivotably adjustable means to retain the mount and the wheel in at least two alternate relative positions spaced angularly about an axis in or in close parallel relation to the radial face of the grinding wheel and such that, when a circular sawblade is mounted on the mount in a first of said positions, a face of a tooth of the sawblade can be brought into contact with the grinding wheel in one desired angular orientation and when in a second of said positions the corresponding face of another tooth of the sawblade may be brought into contact with the grinding wheel at another desired angular orientation.

2. Apparatus according to Claim 1 wherein the said two alternate relative positions are such that in one condition the said face of the tooth of the sawblade will be ground at one angular orientation relative to the plane of the blade of the saw, whereas in the other relative position the corresponding face of another tooth will be ground at an opposite angular orientation relative to the plane of the blade of the saw.

3. Apparatus according to Claim 2 wherein the angular orientation of the face is 50 to the perpendicular to the plane.

4. Apparatus according to any one of the preceding Claims wherein the mount may be additionally retained in a third alternate relative position.

5. Apparatus according to Claim 4 wherein in said third one position the angular orientation of the face is perpendicular to the plane.

6. Apparatus according to any one of the preceding Claims incorporating a further mount, also adapted to be retained in the said alternate relative positions, the mount being located such that in one relative position, when a circular sawblade is mounted on the said further mount another face of a tooth of the sawblade can be brought ito contact with the grinding wheel in one desired angular orientation, and in the other position the corresponding face of another tooth may be brought into contact with the grinding wheel at another desired angular orientation.

7. Apparatus according to any one of the preceding Claims wherein the or each mount is adjustably positionable.

8. Apparatus according to Claim 5 wherein each mount is movable linearly.

9. Apparatus according to any one of the preceding Claims incorporating a table, the or each mount comprising a shaft protruding above the table, but being movable axially along an elongate slot formed in the table, means being provided to secure the mount in position.

10. Apparatus according to Claim 7 wherein the means to secure the mount in position comprise a plate on which the shaft is mounted, but located on the underside of the table, the plate having an elongate aperture therein, a stud from the table passing through the elongate slot, there being locking means on the stud to lock the plate in position.

11. Apparatus according to Claim 10 wherein the shaft is mounted for movement relative to said plate, axially of said slot in the table.

12. Apparatus according to any one of the preceding Claims wherein a guide pin is provided associated with the or each mount, the guide pin being adapted to engage part of the saw blade when mounted upon the mount to retain the sawblade in a desired position.

13. Apparatus according to Claim 12 wherein the or each guide pin is adjustably mounted in position.

14. Apparatus according to Claim 13 wherein each guide pin is mounted on a plate which extends under the table, a stud from the table passing through an elongate slot formed in the plate, there being a lock means co-operating with the stud.

15. Apparatus according to any one of the preceding Claims wherein the or each mount is supported on a support which is pivotally connected to a base.

16. Apparatus according to any one of the preceding Claims wherein means are provided to clamp an electric drill in positon to drive the grinding wheel.

17. Apparatus according to any of Claims 1 to 15 wherein a motor is provided to drive the grinding wheel.

18. Apparatus according to any one of the preceding Claims provided with a mounting block to enable apparatus to be mounted in a vice.

19. Apparatus for sharpening a circular sawblade, comprising a grinding wheel or the like, and support means having first and second locations for a suitable mount which, when in the said first location, enables a sawblade thereon to be moved in a first direction with respect to the grinding wheel and when in the said second location enables a sawblade thereon to be moved in a second direction with respect to the grinding wheel.

20. Apparatus according to Claim 19 wherein said first and second directions are substantially at right angles to one another.

21. Apparatus according to Claim 19 or Claim 20 wherein, when the support means supports the sawblade in a plane containing or parallel to the axis of the grinding wheel, said first direction is substantially parallel to the axis of the grinding wheel and said second direction is substantially parallel to the radial face of the grinding wheel.

22. Apparatus according to Claim 21 wherein the spacing between the radial face of the grinding wheel and the path of movement of the sawblade when on the mount in its said second location can be adjusted between first and second values.

23. Apparatus according to any one of Claims 19 to 22, wherein said support means is positionally adjustable to incline said support means to the plane containing the axis of the grinding wheel.

24. Apparatus according to Claim 23 wherein the angle of inclination is of the order of #O

25. Apparatus according to Claim 23 or Claim 24 wherein said support means is positionally adjustable such as to be inclined selectively to each side of the said plane.

26. A device for setting a circular sawblade, said device comprising a platform, a mount for a sawblade mounted on the platform, the platform having an inclined edge.

27. A device according to Claim 26 wherein the mount is adjustably positioned on the platform.

28. A device according to Claim 27 wherein the mount comprises a shaft extending above the platform, a stud passing from the shaft through an elongate aperture in the platform to a lock means located under the platform, so that the shaft may be selectively positioned.

29. A device according to any one of Claims 26 to 28 wherein the platform is provided with a depending boss, the boss having opposed flat faces to enable the boss to be mounted in a vice.

30. Apparatus according to any one of Claim 1 to 25 in combination with a device according to any one of Claims 26 to 29.

31. Apparatus for sharpening a circular sawblade substantially as herein described with reference to and/or as illustrated in Figures 6 to 14 of the accompanying drawings.

32. A device for setting a circular sawblade substantially as herein described with reference to and/or as illustrated in Figures 15 and 16 of the accompanying drawings.

33. Any novel feature or combination of features disclosed herein.