Abstract: The present invention provides a multi-layered diamond dicing blade. More particularly, the blade is a multi-layered dicing blade comprising an inner layer with a first set of diamond particles and an outer layer overlying the inner layer. The inner layer extends to the outermost periphery of the dicing blade. The outer layer comprises a second set of diamond particles having a size smaller than the first set of diamond particles.

Abstract: A rotary cutting saw including (a) a base disk and (b) a plurality of abrasive segments fixed to an outer circumferential surface of the base disk and are spaced apart from each other in a circumferential direction of the base disk. The base disk has a plurality of slits which are formed in the outer circumferential surface of the base disk and are located between adjacent ones of the abrasive segments in the circumferential direction. Each slit extends inwardly in a radial direction of the base disk from the outer circumferential surface of the base disk. Each of the abrasive segments includes abrasive grains and wear-resistant grains each of which has a size substantially equal to a size of each of the abrasive grains. The wear-resistant grains are exposed on a side surface of each abrasive segment and are regularly arranged on the side surface.

Abstract: The present invention relates to a saw blade for preventing undercut wherein out of the sludge discharging slots arranged together with undercutting segments and ordinary cutting segments on the circumference of a steel wheel, those slots located behind the undercutting segments are dimensioned larger or wider than the slots behind the ordinary cutting segments in order to prevent the breakage and falling-off of the undercut preventing segments and ordinary cutting segments.

Abstract: A method and apparatus for cutting panels or wafers into rectangular shaped die. The apparatus includes a spindle; and a first blade having a first diameter and a second blade having a second diameter smaller that the first diameter each blade mounted to the spindle and spaced apart from one another. The first blade and second blades cut the workpiece based on a direction of movement of said workpiece relative to the first and second blades. The method includes the steps of mounting a first blade having a first diameter and a second blade having a second diameter smaller that the first diameter on a spindle; moving the workpiece relative to the first and second blades; cutting the workpiece along a first direction with the first blade; and cutting the workpiece along a second direction with both the first and second blades simultaneously.

Abstract: A work cutting apparatus comprises a plurality of cutting blades each including a metal plate phase containing a super hard abrasive grain dispersed entirely thereon. A work made of a rare-earth alloy magnet member is submerged in a coolant in a container. The work submerged in the coolant is cut by rotating the cutting blades at a high speed not slower than 8000 rpm and by moving the cutting blades to the work vertically or along a normal line passing a tangential point between the cutting blade and the work. The coolant may be supplied from a hose to a cutting region at a time of the cutting. At the time of cutting, the work is vibrated in a direction parallel to a main surface of the cutting blade and perpendicular to a direction of the cutting. Preferably, the cutting blade has a tip portion formed with a cutout, and a spacer including two main surfaces each having an outer circumferential portion formed with an annular stepped portion is inserted between the cutting blades.

Abstract: A diamond cutting wheel is disclosed. The cutting wheel is capable of reducing frictional resistance, maximizing cutting efficiency, preventing the formation of chippings and discharging cut chips effectively, by means of a plurality of depressions formed on its cutting tip and the continued cutting surfaces of the cutting tip. The cutting wheel comprises a core disk and a sintered cutting tip. The sinter is fitted around and welded to the circumferential end of the core disk. A plurality of depressions are formed on the upper and lower cutting surfaces of the cutting tip while being spaced apart from one another. The depressions formed on the upper cutting surface alternate with the depressions formed on the lower cutting surface so as to allow the cutting surfaces to be continued.

Abstract: A dicing blade is disclosed which is capable of precisely cutting an object at a high speed without causing significant deposition of swarf upon a cut surface even when the object being cut has a large thickness. The dicing blade includes a ring-shaped cutting blade having a cutting edge formed on the peripheral rim of the ring-shaped cutting blade. At least one slit with a depth greater than the thickness of an object to be cut is formed in the cutting edge.

Abstract: A method for making a sintered article comprising providing a plurality of individual blocks of sinterable matrix material, arranging said blocks in abutting relationship to form an assembly of said blocks in a sinter mold wherein said assembly comprises a plurality of said blocks extending in at least one direction thereof and sintering said assembly under pressure in the mold to form an integrated sintered article. The blocks may contain abrasive particles to provide a sintered abrasive article and individual abrasive segments may be extracted from the article.

Abstract: The present invention relates to a saw blade for cutting and finishing the surface of a work piece. The saw blade having a set of teeth disposed about the outer edge for making a cut in a work piece and an abrasive secured to the lateral surface of the saw blade. The abrasive extending laterally outwardly from the surface of the saw blade and providing a finishing effect on the work piece as the abrasive widens the cut beyond the cut of the saw blade teeth. A method for cutting and finishing a surface of a work piece utilizing a saw blade with an abrasive secured to a lateral surface of the blade and the abrasive extending beyond the cut of the saw blade teeth.

Abstract: A rotary cutting saw comprising: a base disk; and a plurality of abrasive segments which are bonded to an outer circumferential surface of the base disk so as to be spaced apart from each other in a circumferential direction of the base disk. The base disk has a plurality of slits which are formed in the outer circumferential surface of the base disk so as to be located between the abrasive segments in the circumferential direction. Each of the slits is defined by a pair of side surfaces opposed to each other in the circumferential direction, and a part-cylindrical surface defining a part of a cylinder whose axis is parallel to the axial direction. The part-cylindrical surface has a circumferential width which is larger than a circumferential distance between the radially inner end portions of the side surfaces. The part-cylindrical surface is smoothly connected to one of the side surfaces without a stepped portion therebetween.

Abstract: A vibration absorbing reed forming process for a piece of sheet metal having a planar surface comprising the steps of cutting a predetermined number of tabs in the piece of sheet metal with a first stamp, aligning the tabs in coplanar fashion with the planar surface with a second stamp, and forming a rib in the tabs by drawing the metal toward the centers of the tabs a predetermined distance thereby creating a gap between the tabs and the piece of sheet metal.

Abstract: A diamond blade S includes a blade portion 2a formed of diamond abrasive grains and fixed to a base plate 1 along the outer circumferential edge thereof. Isolated cutting elements 2b are provided on at least a front or reverse face of the base plate 1 such that the isolated cutting elements 2b are separated from the blade portion 2a fixed along the outer circumferential edge.

Abstract: A method for dust-free cutting of rotating a cutting blade at a predetermined rotational speed to create turbulent flow of air on the face of the cutting blade, directing a liquid coolant against the face of the cutting blade whereby the coolant is dispersed on the spinning blade and captures or entrains the dust particles created and converts the same a harmless slurry.

Abstract: The system of modular elements comprises a plurality of disc elements (11, 12 . . . ) with diamond outer rings (11a, 12a . . . ) for assembling on a single drive spindle with a spacing approximately equal to their thickness; mechanical fragmenting means (19, 20, 21, 22 . . . ) being provided in the spaces between the disc elements to operate essentially by impact, in contrast to the abrasive action of the diamond outer ring of the said disc elements; which disc elements have different diameters forming a broken line that corresponds substantially to the outline of the profile or shaping to be produced on marble, stone or the like; the arrangement being such that the disc elements (11, 12 . . . ) cut grooves by diamond abrasion and the mechanical fragmenting means (19, 20, 21, 22 . . . ) shatter the parts projecting from the grooves with an action of fragmentation by impact and by brittle fracture.

Abstract: A method of fabricating support members for wafer processing fixtures and the produce are disclosed. In the first step of the method, an elongate support member basic form is provided. The basic form has a substantially wedge-shaped cross-section and angular comers. A plurality of wafer-retaining slots are cut along one side of the support member basic form. The support member basic form can include a front surface and a rear surface, with at least one angular comer occurring on each of the surfaces. The comers have a larger radius on the rear than in the front. Attachment structures on terminal ends can be fixed to bases. The elongate support member basic form can be fabricated from an inert crystalline material, such as polycrystalline silicon or monocrystalline silicon.

Abstract: A mold is formed for an building earth boring bit by designing the bit geometry in three dimensions using a computer aided design (CAD) system and then feeding the geometry data of the design to a layering device. The layering device then builds the mold a layer at a time. Materials used in building the mold include, sand, graphite, ceramic, clay, other refractory materials, plastic, rubber and wax. Once the mold is formed, powdered steel or tungsten carbide is poured into the mold and is cured by press molding or infiltrating with a binder forming a bit body. Cutting elements are then inserted in the bit body forming the earth boring bit.

Abstract: A parting tool, including a disc-shaped base member (1), a plurality of ring segment-shaped cutting regions (2) provided at a circumference of the base member (1) separated circumferentially by recesses (4) open at an outer contour of the base member (1) and extending radially through respective cutting regions (2), and at least one elongate opening (5) located in a section (A) of the base member (1), which is limited by two adjacent recesses (4) and the central bore (3) of the base member (1), and extending radially along a section of a spiral line starting from a center of the base member (1).

Abstract: The invention provides a new and improved diamond saw blade for use in cleaning the joints commonly found between concrete sections or slabs. The diamond cutting blade designed in accordance with the present invention provides a thin metal disk with a plurality of abrasive segments secured to the circumferential edge, the blade being adapted for rotation about an axis of rotation. The segments are symmetrically spaced about portions of the periphery of the disk in close end-to-end alignment with one another. A plurality of large elongated openings or gullets are formed in the disk symmetrically spaced in an annular zone located along the periphery of the blade. The gullets occupy at least 30%, and preferably at lest 40% of the outer periphery or circumference of the blade. With this arrangement, the gullets allow the blade to efficiently remove sealant from the joints of concrete.

Abstract: The invention relates to a diamond tip disk saw that does not vibrate during high-speed rotation, enhance the quality of the cut surface, and increase the durability of the saw. The diamond tip disk saw according to the invention comprises of a metal disk having a shaft hole and a plurality of diamond tips on both sides of the periphery. In between the shaft hole and the diamond tips, the saw is provided with a plurality of corrugations forming substantially sinusoidal waves on both sides of the saw. A greater efficiency is obtained when the corrugations are formed in a convex arc coming out of the disk surfaces.

Abstract: A method of manufacturing an electronic component provides a wide area which can be used for forming elements on the surface of a mother substrate and effectively produces an electronic component having excellent performance characteristics. At least a portion of the mother substrate is cut by using a blade having a shape in which a portion thereof butted against the boundary (shoulder) between the electrode arrangement surface and the cut end surface of the mother substrate or a portion which becomes the boundary (shoulder) is inclined at a predetermined angle to form an inclined surface at the boundary (shoulder) or the portion which becomes the boundary (shoulder) so as to expose a part of an electrode at the inclined surface.

Abstract: The slitting assembly includes a grinding wheel with a wide flat grinding face for first cutting a multilayer sheet of soft and compressible, electronic device material, such as lithium-ion polymer material for a uni-cell battery, to a first depth and includes a cutting wheel with a blade-like edge for completing the slit by cutting through uncut layers of the multilayer sheet. The grinding face has a width of at least the thickness of the multilayer sheet, and in practice, the depth of the cut is preferably one half the sheet thickness, which in a uni-cell battery sheet is midway through a separator layer. The grinding wheel is positioned to apply cutting forces to the multilayer sheet in a direction that is substantially parallel to the feed direction to control the application of compressive forces that may compress the soft sheet material and if uncontrolled, may create short circuits between electrically conductive layers.

Abstract: Structurally independent cutting members are formed with abrasive material comprising a plurality of particles protruding through a surface of the retaining material comprising a mesh material for durable cutting members; and, the structurally independent cutting members are selectively continuous or discontinuous and spatially mounted along the working edge of a core. Some of the cutting members or portions of the cutting members are arranged for stock removal, and some are arranged for gauge keeping. Since the individual portions of the cutting portions are separate, more stock removal portions can be included, with fewer gauge keeping portions as may be required. The structurally independent cutting members may have a variety of profile shapes, such as contoured configurations to provide stock removal using high pressure cutting forces applied normal to the cutting face of the workpiece and gauge keeping functions using low pressure cutting forces applied laterally to the cutting face to the workpiece.

Abstract: A tool for treatment of rock, masonry or concrete by drilling, grinding or cutting off, the tool has a plurality of cutting segments each having a plurality of bonded cutting bodies formed as diamond crystals and subjected to an abrasive wear during an operation, a tool base body which carries the cutting segments, and at least one marking provided on at least one segment and forming a wear indicator, the at least one marking being arranged so that it changes during operation of the tool with wear of the cutting segments.

Abstract: A cutting apparatus having a chuck table for holding a workpiece and cutting means for cutting the workpiece held by the chuck table. The cutting means includes a spindle unit, a blade to be attached to a rotating spindle of the spindle unit, a cutting-water supplying nozzle for supplying cutting water to the blade and the workpiece, and an air-blowing nozzle provided adjacent to the blade, for supplying air to a peripheral portion of the blade. The cutting-water supplying nozzle and the air-blowing nozzle are provided on a blade cover for covering the blade. Air-blowing piping for feeding air to the air-blowing nozzle is arranged within the spindle unit. Air forced through the air-blowing piping is fed into the air-blowing nozzle, and is blown against the cutting edge of the blade, eliminating cutting water clinging to the cutting edge to carry out setup for adjusting the blade surely and precisely.

Abstract: A grinding wheel for use in grinding glass, has an outer periphery of abrasive material secured to a body portion made of a lightweight material.

Abstract: Provided are an outer-diameter blade, an inner-diameter blade and cutting machines using both blades for cutting hard material, and a core drill and a core-drill processing machine for forming a hole into hard material, whereby the mechanical processing with reduction in the cutting and/or contact resistance to the tools is realized, so that in the case of the outer-diamond blade, it is prevented from occurring that a to-be-cut object is warped and put into contact to the blade to cause chipping; in the case of the inner-diameter blade, it is prevented from occurring that the blade is bowed and/or a cutting surface is curved; and in the case of the core drill, not only are grinding powder of a workpiece and loosed-off abrasive grains effectively removed to prevent those from being loaded between the drill and the workpiece, but neither of cracking and chipping occur when the drill passes through the workpiece.

Abstract: A method of fabricating support members for wafer processing fixtures is disclosed. In the first step of the method, an elongate support member basic form is provided. The basic form has a substantially wedge-shaped cross-section and angular edges. Next, the edges of the support member basic form are machined to replace the angular edges with substantially arcuate edges. A plurality of wafer-retaining slots are cut along one side of the support member basic form. The support member basic form can include a front surface and a rear surface, with at least one angular edge occurring on each of the surfaces. The step of machining the edges of the support member basic form can be performed as machining the edges on the respective surfaces to radii of between 0.25″ and 5.25″. In an embodiment, the at least one angular edge occurring on the rear surface can be machined to a radius of approximately 1.

Abstract: The invention describes an abrasive system comprising a fiber-backed abrasive disc and a backup pad in which the backup pad has spaced portions removed from the circumference such that the disc overlaps in the area of the removed portions. This has the effect of inhibiting catching of the disc on obstructions and enabling easy swarf removal during operation.

Abstract: The system of modular elements comprises a plurality of disc elements (11, 12 . . . ) with diamond outer rings (11a, 12a . . . ) for assembling on a single drive spindle with a spacing approximately equal to their thickness; mechanical fragmenting means (19, 20, 21, 22 . . . ) being provided in the spaces between the disc elements to operate essentially by impact, in contrast to the abrasive action of the diamond outer ring of the said disc elements; which disc elements have different diameters forming a broken line that corresponds substantially to the outline of the profile or shaping to be produced on marble, stone or the like; the arrangement being such that the disc elements (11, 12 . . . ) cut grooves by diamond abrasion and the mechanical fragmenting means (19, 20, 21, 22 . . . ) shatter the parts projecting from the grooves with an action of fragmentation by impact and by brittle fracture.

Abstract: The present invention relates to a cutting tool and to the method for manufacture thereof. Structurally, the cutting tool (1) in question is provided with an abrasive peripheral surface (2) arranged on the outside of a rigid central core (3) made of a high-rigidity composite material (carbon fibers, glass fibers, synthetic material fibers, carbon fibers bonded with high molecular-weight polymer filaments, carbon fibers bonded with kevlar fibers, sintered carbon) designed to ensure the rigidity of the cutting tool (1) and limit the transmission and amplification of sound waves across the central core (3). The abrasive peripheral surface (2) is preferably formed on a cutting element (5) fixed to an external support (6) rigidly connected to the central core (3) by means of fixing means (7).

Abstract: A cutting edge comprising a mass of superabrasive particles (2) electrodeposited on a thin-walled metallic base member (1) along a border (6) of said base member, wherein said mass (2) forms one or more layers at said border of said base member and fixed thereto, and each layer contains parts comprising at least five superabrasive particles (3) in a row in an extending direction of said base member from said border, so as to improve free-cut performance, decrease kerf width and prolong the life of cutting tool.

Abstract: Abrasive discs with spaced portions removed from the circumference in the form of rounded and elongated V-shapes provide, when in use, complete vision of a workpiece being abraded with reduced tendency to snag on obstructions.

Abstract: The invention relates to a saw blade for cutting, slotting or grooving natural rock and synthetic construction materials, such as concrete, reinforced concrete, brick, asphalt or the like. The saw blade has a sawblade body and a plurality of segments which are arranged on the circumference of the sawblade body and are provided with radially projecting lugs which each bear an abrasive body. The segments are attached to the sawblade body by means of a thermally decoupling tongue-and-groove joint.

Abstract: A method for preparing operative end faces of integrated circuit chips or dies utilizes a beveled cutting blade to impart a desired contact angle to the operative end faces of the chip. The method includes the steps of mounting feet on the chip, trimming the feet where necessary, mounting the chip on a fixture with tape, cutting the end faces, and removing the chip from the fixture.

Abstract: A hand-operated cutting machine comprising a rotatable saw blade (3), a machine body with drive machinery for rotation of the saw blade, a rear manoeuvring handle (20) with control (17, 18) for a drive motor (2) included in said drive machinery and a front handle bow (25) which has the form of a crow which stretches from one side of the machine body over the machine body or over the saw blade to the other side of the machine body. The handle bow is rotatably attached to the machine body in a hinge (26) with an axis of rotation (24) which is located behind the saw blade and is perpendicular to the plane of the saw blade, that both ends of the handle bow are connected to each other through said hinge, and that the handle bow is fixingly adjustable in different rotational positions.

Abstract: A cutting tool is provided which includes a steel metal body and a cemented carbide cutting tip secured to the metal body by a metallic layer. The metallic layer has a high-strength metallic portion and a high-toughness metallic portion. The high-strength metallic portion is made of a metal having a thermal expansion rate between a thermal expansion rate of the metal body and the thermal expansion rate of the cutting tip. The high-toughness metallic portion is located between edge portions of a securing region of the metal body and the cutting tip and has toughness larger than that of the high-strength metallic portion.

Abstract: Segmented cutting tools such core drill bits and diamond saw blades can be made more efficient by hardening a portion of the sides of each of the segments.

Abstract: Proposed is a cutting wheel bladed on the outer periphery of a base wheel with abrasive particles, e.g., particles of diamond and cubic boron nitride, suitable for cutting of a hard and brittle material such as a sintered block of a rare earth-based magnet alloy with good cutting accuracy and low material loss by cutting. The cutting wheel is an integral disk body consisting of a base wheel of a relatively small thickness made from a cemented metal carbide, e.g., tungsten carbide particles cemented with metallic cobalt, instead of conventional steel materials and a cutting blade formed on the outer periphery of the base wheel which contains from 10 to 80% by volume of the abrasive particles having a specified average particle diameter.

Abstract: A wall saw includes a saw head which is displaceable longitudinally on a running rail and has a swivelable saw arm and a saw blade with cutting elements which is detachably fastened to the saw arm. The saw blade is rotatable by means of a drive unit which is mounted on the saw arm and which communicates with a drive arrangement. The saw blade is fastened to the saw arm via a coupling formed of two flange halves (11,17) which slide one inside the other and which can be connected with one another in a detachable manner, one flange half (11) being fastened to the flat side of the saw blade facing the saw arm and the second flange half (17) being arranged at the saw arm.

Abstract: An abrasive tool and a method for its manufacture is provided in which the structural body of the tool, including both the central core and the outer, abrasive-containing portion, is fabricated of a homogeneous material, with abrasive particles dispersed throughout the consumable abrasive-containing portion to grindingly remove workpiece material during rotation of the structural body. A porous lattice of diamond grains encased in a cladding material is first formed by sintering as a continuous annulus or as arcuate segments. The skeletal lattice is then placed in a mold and a homogeneous material in liquid state is introduced into the mold to simultaneously form the central core and to flow into at least a portion of the porous lattice of clad diamond grains to provide an integrally molded, unity tool when the core material solidifies.

Abstract: An electrodeposited diamond wheel including a circular substrate having an attaching aperture formed at the center and a plurality of cooling apertures each formed at a predetermined distance from the attaching aperture in the outer circumferential direction and each at a predetermined pitch. Diamond abrasive particles are electrodeposited on the outer circumference of the circular substrate. Ridges and grooves are formed as corrugations on both surfaces of the circular disc, and diamond abrasive particles are electrodeposited on the outer circumference of the corrugations to form a cutting edge, the cutting edge being formed into a corrugated shape conforming to the substrate. The diamond wheel is suitable for cutting of a composite material of a heat-softening material and a reinforcing material.

Abstract: A wheel cutter blade has a plurality of blade bodies affixed around the periphery of a blade base plate. The inner peripheral portion of each blade body is joined to the blade base plate. The peripheral portion of each blade body also joins to the peripheral portion of the adjacent blade bodies, such that the blade bodies form a consolidated annular molded body. Each blade body contains grinding granules only at the outer peripheral portions of each blade body, so that the grinding granules are not in contact with the blade base plate. The blade bodies may have shallow surface groove channels on the front and rear sides of each blade body, such that an air flow is created. This air flow is useful to reduce friction heat and exhaust ground dust.

Abstract: An abrasive tool for cutting extremely abrasive-resistant materials includes a novel, abrasive segment with a generally crenelated, rectangular appearance. The segment has a single piece vein of a primary abrasive and first bond material extending completely along the length of the segment. The vein transverses the width of the segment at least once in a non-linear path and alternately coincides with inner and outer faces. Gaps between the vein and the faces opposite the vein coincident faces are occupied by a second bond material, and optionally, a secondary abrasive, thus forming multiple, separated abrasive regions. The bottom surface of the segment is attached to a core at an operative perimeter which defines the cutting edge of the tool. The segment can be adapted to conform to the curvature of diverse cutting edges, and thus can be used in rotary and reciprocating saw blades and core drilling bits.

Abstract: In a cutting disc which has a plurality of radial slots connecting with the peripheral edge of the disc, a transverse slot is located at the base of each radial slot. This transverse slot comprises a thin, arcuate slot positioned concavely to the peripheral edge of the disc. Each end of the transverse slot terminates in a hole. All corners formed between the transverse slot, radial slot and holes are smoothly contoured.

Abstract: A saw disk with replaceable cutting members (2) is formed of circular disk member (1) with uniformly spaced recesses (7) extending radially inwardly from an outer edge of the disk member. Each cutting member (2) has a support part (3) and a cutting part (4), with each support part (3) secured in one of the recesses (7) by a removable attachment member (5). The recesses (7) and the disk member (1) are arranged, so that the cutting members are radially insertable. The attachment members (5) are insertable in the axial direction of the disk member. In addition, safety elements (6) are provided for preventing axial displacement of the support part (3) in the recesses (7).

Abstract: A cutting tool insert includes a cutting tip mounted into a first recess of a molded hard refractory compound insert having a second recess of preselected size and shape for locating the insert to a cutting tool. A preferred cutting tip is a diamond and a preferred hard refractory compound is a tungsten carbide with a cobalt binder.

Abstract: Structurally independent cutting members are formed with abrasive material comprising a plurality of particles protruding through a surface of the retaining material comprising a mesh material for durable cutting members; and, the structurally independent cutting members are selectively continuous or discontinuous and spatially mounted along the working edge of a core. Some of the cutting members or portions of the cutting members are arranged for stock removal, and some are arranged for gauge keeping. Since the individual portions of the cutting portions are separate, more stock removal portions can be included, with fewer gauge keeping portions as may be required. The structurally independent cutting members may have a variety of profile shapes, such as contoured configurations to provide stock removal using high pressure cutting forces applied normal to the cutting face of the workpiece and gauge keeping functions using low pressure cutting forces applied laterally to the cutting face to the workpiece.

Abstract: The subject invention is a cutting disc having a plurality of radial slots connecting with the peripheral edge of the disc which form multiple tabs integrally mounted to the cutting disc with the tabs protruding outwardly from the peripheral edge of the cutting disc. There is at least one tab for each support segment located between directly adjacent radial slots. When fixedly mounting of the cutting segments into the support segments, the cutting segment is also fixed to a tab.

Abstract: A blade mounting structure in which a mounted blade is rotated in a well-balanced condition and further the blade can be easily attached to and detached from the apparatus is provided, which structure comprises a mount including a flange and a first cylindrical engagement portion and a first screw portion; a cutting blade including a second engagement portion; and a screw member including a second screw portion, wherein the cutting blade is mounted onto the mount so that the first engagement portion is engaged with the second engagement portion, and the second screw portion is screwed into the first screw portion and wherein the tolerance of the engagement portions, the thickness of the first engagement portion, the gap between the flange and the first engagement portion, and the diameter of the flange are selected to have a particular relationship such that the engagement portions are not engaged under an inappropriate contact condition when the blade is inserted into the mount.