JP2003340644A - Bimetal band saw blade - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To increase resistance to a fatigue failure of a bimetal band saw blade 17 while enabling a small work to be cut. <P>SOLUTION: A saw blade body 19 is formed with cutting teeth 29 composed of numerous cutting teeth groups 27 of the same shapes by hobbing from the side of a blade material 23. Each group 27 includes a plurality of first cutting teeth 31 each having the deepest part 31a of a galette 35 positioned on the blade material 23 or at the melted joint 25 between a back material 21 and the blade material 23, and an appropriate number of second cutting teeth 33 each having the deepest part 33a of a galette 37 positioned on the back material 21. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bimetal band saw blade used for a band saw machine such as a horizontal band saw machine for cutting a work.

[0002]

A band saw blade is used in a band saw machine such as a horizontal band saw machine for cutting a work. The band saw blade is formed into an endless shape by welding and then used as a main wheel and a driven wheel in the band saw machine. It is attached so that it can be hung. Further, the band saw blade is twisted and guided by the saw blade insert of the band saw so that the tooth tips of the parts of the band saw blade that pass through the cutting region are substantially perpendicular to the work. Then, while the drive wheel is rotationally driven to circulate the band saw blade, the band saw blade is moved to the work side together with the saw blade housing in the band saw machine, whereby the work is cut by the band saw blade. Here, during the cutting process, the band saw blade is repeatedly subjected to bending stress due to contact with the wheel (main driving wheel, driven wheel) and torsion stress due to contact with the saw blade insert.

In recent years, band saw blades have made remarkable progress through research and development, and there are band saw blades, so-called bimetal band saw blades, which can sufficiently cope with bending stress and twisting stress and are also suitable for cutting difficult-to-cut workpieces such as stainless steel. It has been developed.

FIG. 6 shows a conventional bimetal band saw blade 1, FIG. 6 (a) shows the state before the gear cutting process, and FIG. 6 (b) shows the gear cutting process. A portion of the later bimetal band saw blade 1 is shown.

As shown in FIG. 6, a conventional bimetal band saw blade 1 has a saw blade body 3 as a base, and the saw blade body 3 has a body material 5 having a high elastic limit and a blade material 7 having a high hardness. Are welded together, and a melt-bonded portion 9 (hatched portion) is formed between the body material 5 and the blade material 7. Further, as shown by a dotted line in FIG. 6A, a cutting tooth group 11 is formed on the saw blade body 3 from the blade material 7 side by gear cutting, and the cutting tooth group 11 has the deepest depth of the gullet 15. Part 13a
Will have a number of cutting teeth 13 located on the body material 5. Here, the deepest portion 13a of the gullet 15 is a ridge line that constitutes the gullet 15 and refers to a region A that is closest to the saw blade back surface 16.

[0006]

By the way, the cutting teeth 13
In order to suppress the damage such as the tooth chipping and the like and improve the cutting efficiency, it is necessary to select the bimetal band saw blade 1 having the tooth pitch P of the cutting teeth 13 according to the size of the work (not shown). In other words, when cutting a large work (thick work, thick plate work, etc.), a bimetal band saw blade 1 having a long tooth pitch P is used, and a small work (thin work, thin plate work, etc.) is used. 2), it is necessary to use a bimetal band saw blade 1 having a short tooth pitch P. On the other hand, the tooth pitch of the cutting tooth 13
When P is shortened, the depth of the gullet 15 becomes shallower, and there is a certain limit for the reason of manufacturing the saw blade body 3 in order to shorten the length of the blade material 7 in the saw width direction (vertical direction in FIG. 6). is there.

Therefore, when the tooth pitch P of the cutting teeth 13 is gradually shortened to cut a very small work,
The deepest part of the large number of gullets 15 where the bending stress and the twisting stress tend to concentrate is located at the blade material 7 or the melt-bonded part (hatched part) 9. Therefore, the resistance force of the bimetal band saw blade 1 against fatigue fracture is weakened, and the bending stress and the torsion stress tend to cause cracks, scratches and the like from the deepest part of the gullet 15, and the fatigue life of the bimetal band saw blade 1 is shortened. There is a problem.

[0008]

In a bimetal band saw blade used in a band saw machine, a body material having a high elastic limit and a blade material having a high hardness are joined by welding. A saw blade main body is provided as a base, and a cutting tooth group is formed on the saw blade main body from the blade portion material side by gear cutting. In this cutting tooth group, the deepest part of the gullet is the blade portion material or the body material. And a large number of first cutting teeth located at the fusion-bonded portion of the blade material, and the deepest part of the gullet is composed of an appropriate number of second cutting teeth located at the body material.

According to the invention specifying matter of claim 1,
Since the deepest part of the gullet of the first cutting teeth is located at the blade material or the fusion joint, the deepest part of the gullet at the first cutting teeth is located at the blade material or the fusion joint. Thus, the gullets in each of the multiple first cutting teeth can be shallow. As a result, the tooth pitch of the large number of first cutting teeth can be made shorter, and the tooth pitch can be made shorter even when viewed from the entire cutting tooth group.

Further, since the deepest part of the gullet of the second cutting tooth is located in the body material having a high elastic limit and is deeper than the deepest part of the gullet of the first cutting tooth, a proper number of the second cutting tooth is formed. Bending stress and torsion stress can be concentrated in the deepest part of the gullet in the cutting tooth.

In addition to the above operation, under the condition that the band saw blade is wound around the driving wheel and the driven wheel of the band saw machine, the driving wheel is rotationally driven to circulate the band saw blade while the saw blade housing of the band saw machine is being run. At the same time, the band saw blade is moved to the work side. With this, the work is cut.

According to the second aspect of the present invention, in a bimetal band saw blade used for a band saw machine, a saw blade main body obtained by joining a body material having a high elastic limit and a blade material having a high hardness by welding is used as a base. The saw blade body is provided with a cutting tooth group consisting of a large number of cutting tooth groups of the same shape by tooth cutting from the blade material side, and each cutting tooth group has the deepest part of the gullet at the blade material or A plurality of first cutting teeth located at the fusion-bonded portion of the body material and the blade material, and a proper number of second cutting teeth at the deepest part of the gullet located in the body material. And

According to the invention specifying matter of claim 2,
Since the deepest part of the gullet of the first cutting teeth is located at the blade material or the fusion joint, the deepest part of the gullet at the first cutting teeth is located at the blade material or the fusion joint. Thus, the gullets in each of the multiple first cutting teeth can be shallow. As a result, the tooth pitch of the large number of first cutting teeth can be made shorter, and the tooth pitch can be made shorter even when viewed from the entire cutting tooth group.

Further, since the deepest part of the gullet of the plurality of second cutting teeth is located in the body material having a high elastic limit and is deeper than the deepest part of the gullet of the first cutting tooth, an appropriate number of the second cutting teeth are formed. Bending stress and torsion stress can be concentrated in the deepest part of the gullet in the tooth.

In addition to the above operation, under the condition that the band saw blade is wound around the driving wheel and the driven wheel in the band saw machine, the driving wheel is rotationally driven to circulate the band saw blade while the saw blade housing in the band saw machine is being run. At the same time, the band saw blade is moved to the work side. With this, the work is cut.

In the invention described in claim 3, in addition to the matters specifying the invention described in claim 1 or 2,
The flank forming the gullet of the cutting tooth is formed in a stepped shape.

According to the invention specifying matter of claim 3,
In addition to the action of the invention specifying matter according to claim 1 or claim 2, since the flank forming the gullet of the second cutting tooth has a stepped shape, the deepest part of the gullet in the second cutting tooth is formed. The second cutting tooth pitch can be made shorter by making the gullet deeper so that is located in the body material.

In the invention described in claim 4, in addition to the matters specifying the invention described in claim 1 or claim 2,
It is characterized in that the clearance angle forming the gullet of the cutting tooth is larger than the clearance angle forming the gullet of the first cutting tooth.

According to the invention specifying matter of claim 4,
In addition to the action by the invention specifying matter according to claim 1 or claim 2, the clearance angle forming the gullet of the second cutting tooth is made larger than the clearance angle forming the gullet of the first cutting tooth. Since it is configured, even if the gullet in the second cutting tooth is deepened so that the deepest part of the gullet in the second cutting tooth is located in the body material, the plurality of second cutting tooth pitches are further shortened. be able to.

According to a fifth aspect of the invention, in addition to the matters specifying the invention of the third or fourth aspect, the tooth pitch of the cutting teeth is the same when viewed from the entire cutting tooth group. It is characterized by

According to the invention specifying matter of claim 5,
The same action as the action according to the invention specifying matter according to claim 3 or 4 is achieved.

According to a sixth aspect of the invention, in addition to the matters specifying the invention according to any one of the first to fifth aspects, in addition to the cutting tooth group as a whole, adjacent or It is characterized in that a plurality of second cutting tooth groups each including a plurality of adjacent second cutting teeth are arranged at appropriate intervals.

According to the invention specifying matter of claim 6,
In addition to the action by the invention specifying matter according to any one of claims 1 to 5, when viewed from the entire cutting tooth group, a second cutting tooth including a plurality of second cutting teeth adjacent to or adjacent to each other Since the cutting tooth groups are configured to be arranged at appropriate intervals, bending stress,
The region where the torsional stress concentrates is not limited to a small number of regions, but can be dispersed in a large number of regions in the entire cutting tooth group.

According to the invention described in claim 7, in addition to the matters specifying the invention described in any one of claims 1 to 6, the body material is a special alloy steel. hand,
It is characterized in that the blade material is cemented carbide or high speed tool steel.

According to the invention specifying matter of claim 7,
The same operation as the operation according to the invention specifying matters according to any one of claims 1 to 6 is achieved.

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

1 to 3 show a bimetal band saw blade according to an embodiment of the first invention.

As shown in FIG. 1, a bimetal band saw blade 17 according to an embodiment of the present invention has a saw blade body 19 as a base, and the saw blade body 19 has a body material 21 having a high elastic limit and hardness. The high blade material 23 is joined by electron beam welding, laser welding, or the like. Here, the body material 21 is, for example, a special alloy steel such as spring steel, the blade material 23 is cemented carbide or high speed tool steel, and the body material 21 and the blade material 23 are melted. Joining part 25 (hatched part)
Is formed.

Cutting of the saw blade main body 19 from the side of the blade material 23 by tooth cutting, comprising a plurality of cutting tooth groups 27 of the same shape (only two cutting tooth groups 27 are shown in FIG. 1). A group of teeth 29 is formed. Each cutting tooth group 27 includes two first cutting teeth 31 in which the deepest part 31 a of the gullet 35 is located in the fusion joint 25, and the gullet 3.
7 second deepest part 33a is located in the body material 21
A cutting tooth 33 is provided. The deepest part 31 a of the gullet 35 of the first cutting tooth 31 may be located on the blade material 23.

Here, the tooth pitch of the first cutting teeth 31 is P1 and the tooth pitch of the second cutting teeth 33 is P2 which is longer than P1. The depth of the deepest part of the gullet 35 in the first cutting tooth 31 is H1, and the depth of the deepest part of the gullet 37 in the second cutting tooth 33 is H2 deeper than H1. The clearance angle of the first cutting teeth 31 is the same as the clearance angle of the second cutting teeth 33.

Further, as shown in FIG. 2, the second cutting teeth 33
The flank 33f that constitutes the gullet 37 may be formed in a stepped shape, and as shown in FIG. 3, the clearance angle (N2 °) that constitutes the gullet 37 of the second cutting tooth 33 is the same as that of the first cutting tooth. Three
It is configured to be larger than the clearance angle (N1 °) that constitutes the first gullet 35. In the above case, the first
The tooth pitch of the cutting tooth 31 and the tooth pitch of the second cutting tooth 33 are both P1, and the tooth pitch is the same when viewed from the entire cutting tooth group 29.

Next, the operation of the embodiment of the first aspect of the invention will be described. The deepest part 31a of the gallet 35 of the first cutting teeth 31 in the entire group of cutting teeth 29 is melt-bonded to each other.
Each of the plurality of gullets 35 can be shallow so as to be located on (or the blade material 23). Thereby, the tooth pitch of the large number of first cutting teeth 31 can be further shortened, and the cutting tooth group 2
The tooth pitch can be shortened even when viewed from the whole 9.

Further, when viewed from the entire cutting tooth group 29, the multiple gullets 37 can be deepened so that the deepest part 33a of the gallets 37 of the large number of second cutting teeth 33 is located in the body material 21. As a result, the cutting tooth group 29 is cut during the cutting process.
Galettes 37, which have high elasticity limit in
Bending stress and torsion stress can be concentrated in the deepest part of the.

In addition to the above operation, the bimetal band saw blade 17 is rotated by driving the bimetal band saw blade 17 around a main drive wheel (not shown) and a follower wheel (not shown) in the band saw machine. Saw blade housing (not shown) in the band sawing machine while circulating
At the same time, the bimetal band saw blade 17 is moved to the work side.
With this, a work (not shown) is cut.

As described above, according to the first embodiment of the present invention, the tooth pitch can be further shortened as viewed from the entire cutting tooth group 29, and the deepest part of the galette 37, which is a portion of the cutting tooth group 29 having a high elastic limit, can be obtained. Since the bending stress and the torsional stress can be concentrated on the portion, it is possible to cut a very small work piece, and the resistance force against the fatigue fracture of the bimetal band saw blade 17 becomes strong, so that from the deepest portion of the gullets 35, 37. The fatigue life of the bimetal band saw blade 17 can be improved by suppressing the occurrence of cracks and fractures.

Further, in the bimetal band saw blade 17 as shown in FIG. 2 or FIG. 3, a large number of gullets 37 are arranged so that the deepest part of a large number of gullets 37 is located in the body material 21.
Even if the depth is made deeper, the tooth pitch of the large number of second cutting teeth 33 can be shortened to be the same as the tooth pitch P1 of the large number of first cutting teeth 31. Will be more efficient.

FIG. 4 shows a bimetal band saw blade 39 according to the second embodiment of the present invention. The first embodiment of the construction of the bimetal band saw blade 39 according to the second embodiment of the present invention will be described below. Only the configuration different from the bimetal band saw blade 17 according to the embodiment of the invention will be described. The second
Among the plurality of constituent elements of the bimetal band saw blade 39 according to the embodiment of the invention, the same constituent elements as those of the bimetal band saw blade 17 according to the embodiment of the first invention are designated by the same reference numerals in the drawings. The description is omitted.

As shown in FIG. 4, the bimetal band saw blade 39 according to the second embodiment of the present invention is based on the saw blade body 19 as with the bimetal band saw blade 17 according to the first embodiment of the present invention. The saw blade body 19 comprises a large number of cutting tooth groups 41 of the same shape by cutting from the blade material 23 side (only one cutting tooth group 41 is shown in FIG. 4). A cutting tooth group 43 is formed. Each cutting tooth group 41 has a galette 49
Deepest part 45a of the blade part material 23 or the five first cutting teeth 45 located in the fusion joint part 25, and the deepest part 47a of the gullet 51 located in the body part material 21 of the two second cutting teeth 4
Equipped with 7.

Here, the tooth pitch of the five first cutting teeth 45 is P1, P2, P3, P4, P5 from the right side in the figure (P4 <P3 <
P5 <P2 <P1), the tooth pitch of the two second cutting teeth 47 is P6 and P7 from the right side in the figure (P6 and P7 are considerably longer than P1,
P6 <P7). Further, the depth of the deepest part of the gullet 49 in the five first cutting teeth 45 is H1, H2, H3, H4 from the right side in the drawing,
H5 (H4 <H3 <H5 <H2 <H1), the depth of the deepest part of the galette 51 in the two second cutting teeth 47 is H6 and H7 (H6 and H7 are considerably deeper than H1 and H6 <H7). The clearance angle of the first cutting teeth 45 is the same as the clearance angle of the second cutting teeth 47.

Further, since the two second cutting tooth groups 47 are arranged so as to be adjacent to each other in each cutting tooth group 41, the two adjacent cutting tooth groups 43 are adjacent to each other when viewed from the entire cutting tooth group 43.
A plurality of second cutting tooth groups each including one second cutting tooth 47 are arranged at equal intervals.

Next, the operation of the second embodiment of the invention will be described. As seen from the whole cutting tooth group 43, the deepest portion 45a of the gullet 49 of the large number of first cutting teeth 45 is melt-bonded to each other.
The multiple gullets 49 can each be shallow so that they are located (or the blade material 23). Thereby, the tooth pitch of the large number of first cutting teeth 45 can be further shortened, and the cutting tooth group 4
The tooth pitch can be shortened even when viewed from the whole 3.

Further, the gullet 51 in the large number of second cutting teeth 47 can be deepened so that the deepest part 47a of the gullet 51 of the large number of second cutting teeth 47 is located in the body material 21 when viewed from the whole cutting tooth group 43. . Thereby, during the cutting process, the bending stress and the torsional stress can be concentrated in the deepest part of the plurality of gullets 51, which is a part of the cutting tooth group 43 having a high elastic limit. Here, in the second cutting tooth group 47, the bending stress and the torsion stress are concentrated in the deepest part of the gullet 51 having the depth H7 than in the deepest part of the gullet 51 having the depth H6.

Further, when viewed from the whole cutting tooth group 43, a plurality of second cutting tooth groups consisting of two adjacent second cutting teeth 47 are arranged at equal intervals. The region where the torsional stress concentrates is not limited to a small number of regions, but can be dispersed in a large number of regions in the entire cutting tooth group 43.

In addition to the above operation, under the condition that the bimetal band saw blade 39 is wound around a main driving wheel (not shown) and a driven wheel (not shown) in the band saw machine, the main driving wheel is rotated to drive the bimetal band saw blade 39. Saw blade housing (not shown) in the band sawing machine while circulating
At the same time, the bimetal band saw blade 39 is moved to the work side.
With this, a work (not shown) is cut.

According to the second embodiment of the present invention, in addition to the same effect as that of the first embodiment of the present invention, the cutting tooth group 43 has only a few portions where bending stress and torsion stress are concentrated. The number of parts is not limited to the number of parts, and the cutting teeth group 43 can be dispersed in a large number of parts, so that the fatigue life of the bimetal band saw blade 39 can be further improved.

FIG. 5 shows a bimetal band saw blade 53 according to an embodiment of the third invention. The structure of the bimetal band saw blade 53 according to the embodiment of the third invention is the same as that of the second invention. The bimetal band saw blade 39 according to the second embodiment has substantially the same configuration as that of the bimetal band saw blade 39 according to the second embodiment. Only the configuration different from the blade 39 will be described. In the configuration of the bimetal band saw blade 53 according to the embodiment of the third invention, the same components as those of the bimetal band saw blade 39 according to the embodiment of the second invention are denoted by the same reference numerals in the drawings. And the description is omitted.

As shown in FIG. 5, the saw blade main body 19 forming the base of the bimetal band saw blade 53 according to the third embodiment of the present invention has a large number of identical shapes from the blade material 23 side by tooth cutting. A cutting tooth group 57 composed of the cutting tooth group 55 (only one cutting tooth group 55 is shown in FIG. 5) is formed. Each cutting tooth group 5
5 is two first cutting teeth 59 in which the deepest part 59a of the gullet 63 is located in the blade material 23 or the fusion joint 25,
The deepest part 61 a of the gullet 65 has three second cutting teeth 61 located on the body material 21. The three second
The cutting teeth 61 are arranged so as to sandwich the first cutting teeth 59.

Here, the tooth pitch of the two first cutting teeth 59 is P1, and the tooth pitch of the three second cutting teeth 61 is P2 which is larger than P1. Further, the depth of the deepest part of the gullet 63 in the first cutting tooth 59 is H1, and the second cutting tooth 6 is
The depth of the deepest part of the gullet 65 in 1 is deeper than H1
It is H2. The clearance angle of the first cutting tooth 59 is the second
It is the same as the clearance angle at the cutting tooth 61.

Further, since the two second cutting teeth 61 are arranged on both the left and right sides in the drawing in each cutting tooth group 55, when viewed from the entire cutting tooth group 57, two adjacent second cutting teeth 61 are provided. A plurality of the second cutting tooth groups are arranged at equal intervals.

Therefore, according to the embodiment of the third invention, the same operation and effect as those of the embodiment of the second invention are obtained.

The present invention is not limited to the above description of the embodiments of the invention, but can be implemented in various other modes by making appropriate changes.

[0052]

According to the invention described in any one of claims 1 to 7, (claim 1 or 2)
According to the invention specifying matters described in 1), the tooth pitch can be further shortened when viewed from the entire cutting tooth group, and the bending stress is at the deepest part of the gullet in the second cutting tooth, which is a portion having a high elastic limit in the cutting tooth group, Since it is possible to concentrate the torsional stress, it enables cutting of very small workpieces, while increasing the resistance to fatigue fracture of the bimetal band saw blade, and suppressing the occurrence of cracks and fractures from the deepest part of the galette. As a result, the fatigue life of the bimetal band saw blade can be improved.

According to the invention of any one of claims 3 to 7 (according to the matters specifying the invention of claim 3 or 4), a plurality of second cutting teeth Even if the gullet in the plurality of second cutting teeth is deepened so that the deepest part of the gullet in is located in the body material, the tooth pitch of the plurality of second cutting teeth can be further shortened. The efficiency of cutting of small workpieces is further improved.

According to the invention of claim 6 or claim 7 (according to the invention specifying matter of claim 6), only a small number of parts of the cutting tooth group where bending stress and torsion stress are concentrated. It is possible to further improve the fatigue life of the bimetal band saw blade, because it is possible to disperse the cutting tooth group in a large number of parts instead of being limited to the part.

[Brief description of drawings]

FIG. 1 is a view showing a bimetal band saw blade according to an embodiment of the first invention.

FIG. 2 is a view showing another mode of the bimetal band saw blade according to the embodiment of the first invention.

FIG. 3 is a view showing another mode of the bimetal band saw blade according to the embodiment of the first invention.

FIG. 4 is a diagram showing a bimetal band saw blade according to an embodiment of the second invention.

FIG. 5 is a view showing a bimetal band saw blade according to an embodiment of the third invention.

FIG. 6 is a view showing a conventional bimetal band saw blade.

[Explanation of symbols]

17 Bimetal band saw blade 19 Saw blade body 21 Body material 23 Blade material 25 Fusion joint 27 Cutting tooth group 29 cutting teeth 31 First cutting tooth 33 Second cutting tooth 35 Galette 37 Galette 39 Bimetal band saw blade 41 Cutting tooth group 43 cutting teeth 45 First cutting tooth 47 Second cutting tooth 49 Galette 51 galette 53 Bimetal Band Saw Blade 55 Cutting tooth group 57 cutting teeth 59 First cutting tooth 61 Second cutting tooth 63 galette 65 Galette

Claims (7)

[Claims] 1. A bimetal band saw blade for use in a band saw machine, comprising a saw blade body formed by welding a body material having a high elastic limit and a blade material having a high hardness by welding, and the saw blade body having the blade portion. A cutting tooth group is formed from the material side by gear cutting, and the cutting tooth group includes a large number of first teeth in which the deepest part of the gullet is located at the melting joint between the blade material or the body material and the blade material. A bimetal band saw blade comprising a cutting tooth and a proper number of second cutting teeth positioned at the deepest part of the galette in the body material. 2. A bimetal band saw blade for use in a band saw machine, comprising a saw blade body formed by welding a body material having a high elastic limit and a blade material having a high hardness by welding, and the saw blade body having the blade portion. A cutting tooth group consisting of a large number of cutting tooth groups of the same shape is formed from the material side by gear cutting, and each cutting tooth group has the deepest part of the gullet of the blade material or the body material and the blade material. A bimetal band saw blade, comprising: a plurality of first cutting teeth located at the fusion joint and an appropriate number of second cutting teeth located at the deepest part of the gullet in the body material. 3. The bimetal band saw blade according to claim 1, wherein the flank forming the gullet of the second cutting tooth has a stepped shape. 4. The clearance angle forming the gullet of the second cutting tooth is configured to be larger than the clearance angle forming the gullet of the first cutting tooth. Item 2. The bimetal band saw blade according to Item 2. 5. The bimetal band saw blade according to claim 3, wherein the cutting teeth have the same tooth pitch when viewed from the entire cutting tooth group. 6. A plurality of second cutting tooth groups including a plurality of second cutting teeth adjacent to or adjacent to each other when viewed from the entire cutting tooth group are arranged at appropriate intervals. The bimetal band saw blade according to any one of claims 1 to 5. 7. The material of the body is a special alloy steel, and the material of the blade is a cemented carbide or a high speed tool steel, according to any one of claims 1 to 6. A bimetal band saw blade according to claim.