Traditional saw blades have a cutting edge provided with a plurality of teeth. The teeth have the same pitch and/or profile along the entire length of the cutting edge. It can be difficult to start off a saw cut with such a saw, especially if the teeth have a large pitch, since the cutting edge of the saw blade will tend to jump until a reasonably deep guide cut has been formed.

It is known, for example from US 4,265, 285, to provide a combination cross-and rip-cut handsaw in which teeth having different profiles and/or pitches are provided along the cutting edge, the teeth being arranged in repeating groups of four, the pitch of the teeth decreasing in a forward direction within each group.

It is also known, for example from US 2002/0194975 A, to provide a handsaw having a cutting edge with multiple tiers of teeth, such that a first tier to engage a material to be cut has fast cutting characteristics, with subsequent tiers cutting away kerf surfaces left by the preceding tier and thus cutting a new smoother kerf.

According to a first aspect of the present invention, there is provided a saw blade having first and second cutting edges each provided with cutting means, wherein the cutting means of the first cutting edge have a finer cutting characteristic than the cutting means of the second cutting edge, characterised in that the cutting means of the first cutting edge comprise abrasive particles bonded to the first cutting edge.

The cutting means of the second cutting edge may comprise saw teeth with a predetermined pitch and/or profile. Alternatively, the cutting means of the second cutting edge may comprise abrasive particles bonded to the second cutting edge,

these abrasive particles being larger or coarser than the abrasive particles bonded to the first cutting edge.

The abrasive particles may include refractory metal grits, such as sintered tungsten carbides and the like which can be brazed or otherwise boded onto the cutting edge.

Diamond or diamond-like carbon particles, crystalline materials, metal oxides or borides and any other hard abrasive particles may be used, provided that these can be suitably bonded to the cutting edge.

In one preferred embodiment, the first and second cutting edges are formed together on one edge of the saw blade so as to form a single cutting edge with different cutting characteristics along its length. It is particularly preferred that the first cutting edge comprises an end or leading portion of the cutting edge, with the second cutting edge comprising a remaining or trailing portion of the cutting edge, although this configuration may be reversed in some embodiments.

The remaining or trailing portion of the cutting edge is that portion which is adjacent to a handle when one end of the saw blade is attached to a handle to form a hand saw.

Where the first and second cutting edges together form a single cutting edge along one edge of the saw blade, the first cutting edge may comprise less than half of a total length of the cutting edge as a whole, preferably less than a third of the total length, even more preferably less than a quarter of the total length and most preferably less than an eighth of the total length.

In another preferred embodiment, the first and second cutting edges are respectively formed as opposed edges of the saw blade, thus providing a saw blade with one edge having a finer cutting characteristic than the other.

According to a second aspect of the present invention, there is provided a saw blade having a cutting edge provided with cutting means, wherein a first, end region of the

cutting edge is provided with cutting means having a finer cutting characteristic than a second, remaining region of the cutting edge, characterised in that the cutting means on the first region of the cutting edge comprise abrasive particles bonded to the cutting edge, and in that the cutting means on the second region of the cutting edge comprise saw teeth or abrasive particles that are coarser than those bonded to the first region of the cutting edge.

The end region of the cutting edge is preferably the end located distal from a handle when the saw blade is fitted therewith to form a saw. Alternatively, the end region may be located proximal to the handle.

The end region may comprise less than half of a total length of the cutting edge, preferably less than a third of the total length, even more preferably less than a quarter of the total length and most preferably less than an eighth of the total length.

In one particularly preferred embodiment of the present invention, the cutting edge with the finer cutting characteristic is provided with abrasive particles bonded to the cutting edge and the other cutting edge is provided with saw teeth having a pitch of 5 to 10 teeth per inch (2 to 4 teeth per centimetre), preferably 7 teeth per inch (2. 8 teeth per centimetre). Alternatively, saw teeth having a pitch of 20 to 30 teeth per inch (8 to 12 teeth per centimetre), for example 26 teeth per inch (10.4 teeth per centimetre), may be provided. Alternatively, the other cutting edge may have bonded thereto abrasive particles that are coarser or larger than those bonded to the cutting edge with the finer cutting characteristics.

In some embodiments, the saw teeth (where provided) have a constant pitch and/or profile. Alternatively, the saw teeth may have a varying pitch and/or profile, for example as disclosed in US 4,265, 285.

Preferably, the cutting edge or edges is/are substantially straight or linear in extension.

When cutting an article, such as a piece of wood, with the saw blade of embodiments of the present invention, a user will first use the region of the cutting edge with the finest cutting characteristics to form a guide cut. Because of the fine cutting characteristic, it is relatively easy to form a guide cut without the saw blade skipping or jumping and without causing excessive or any splitting of the edge of the material.

Once a sufficiently deep guide cut has been formed, the user then applies a region of the cutting edge with coarser cutting characteristics so as to speed the cutting process.

Where the saw blade is configured with a single cutting edge, a user simply applies different regions of the cutting edge to the article being cut.

When a saw blade of the present invention with two opposed cutting edges is fitted with a handle so as to form a handsaw, the handle is preferably configured so as to allow comfortably operation of the handsaw both with the finer cutting edge facing downwardly and with the coarser cutting edge facing downwardly. In other words, the handle should be designed so as to enable comfortable use of the handsaw in two opposed orientations. Accordingly, the handle may advantageously be substantially symmetrical about a plane extending longitudinally along, but substantially perpendicular to, the saw blade between the opposed cutting edges.

When using a saw blade as described above, a guide cut or groove is first formed in a work piece by using the cutting edge with the finer cutting characteristic. Once a sufficient depth of guide cut or groove has been attained, the saw blade is removed and turned over, and cutting then continues using the coarser cutting edge.

Apart from providing increased ease of use, embodiments of the present invention also provide for greater user safety, since skipping or jumping of the saw blade is ameliorated.

Saw blades of embodiments of the present invention may take any appropriate form, including ripsaw blades, crosscut saw blades, panel saw blades, tenon saw blades,

hacksaw blades, padsaw blades, coping saw blades and any other appropriate saw blades.

According to a third aspect of the present invention, there is provided a saw including a saw blade of the first or second aspects of the present invention.

It is to be appreciated that, although the saw blade of embodiments of the present invention has been described in connection with a handsaw, it may advantageously be used in power saw applications.

For a better understanding of the present invention and to show how it may be carried into effect, reference shall now be made by way of example to the accompanying drawing, in which: FIGURE 1 shows a first embodiment of the present invention; FIGURE 2 shows a second embodiment of the present invention ; FIGURE 3 shows a third embodiment of the present invention ; and FIGURE 4 shows a fourth embodiment of the present invention.

Figure 1 shows a handsaw comprising a saw blade 1 fitted with a handle 2. The saw blade 1 has a substantially straight or linear cutting edge indicated generally at 3. An end region 4 of the cutting edge 3, distal from the handle 2, is provided with abrasive particles 5. The end region 4 comprises less than one eighth of a total length of the cutting edge 3. A remaining region 6 of the cutting edge 3, proximal to the handle 2, is provided with teeth 7 having a cutting characteristic that is coarser than a cutting characteristic of the abrasive particles 5..

In use, the end region 4 of the cutting edge 3 is placed upon a work piece to be cut, and the user applies several short, reciprocating strokes of the saw blade 1 such that only the end region 4 of the cutting edge 3 is used to form a start groove in the work piece. Once a satisfactory start groove has been formed, the user may then apply progressively longer strokes of the saw blade 1 such that the larger teeth 7 come into use.

Figure 2 shows a handsaw similar to that of Figure 1, with like parts being labelled as in Figure 1. However, instead of saw teeth, the remaining region 6 of the cutting edge 3 is provided with abrasive particles 8 having a coarser cutting characteristic than the abrasive particles 5 on the end region 4.

Figure 3 shows an alternative embodiment of the present invention, comprising a saw blade 1 fitted with a handle 2 as before. In this embodiment, however, the saw blade 1 has two opposed cutting edges 9, 10. Cutting edge 10 is provided with abrasive particles 5 bonded thereto along its entire length, and cutting edge 9 is provided with saw teeth 7 having a coarser cutting characteristic than the abrasive particles 5.

Figure 4 shows a variation of the embodiment of Figure 3. In this case, the cutting edge 9 is provided with abrasive particles 8 having a coarser cutting characteristic than the abrasive particles 5 on the opposed cutting edge 10.

In use, the saw of Figures 3 and 4 is applied to an article to be cut using the cutting edge 10 with the finer cutting characteristic so as to form a guide cut. The saw is then turned over and the cutting edge 9 with the coarser cutting characteristics is used to continue cutting the article.

The preferred features of the invention are applicable to all aspects of the invention and may be used in any possible combination.

Throughout the description and claims of this specification, the words"comprise" and"contain"and variations of the words, for example"comprising"and "comprises", mean"including but not limited to", and are not intended to (and do not) exclude other components, integers, moieties, additives or steps.