Rotatable Cutting Tool

A method for fabricating a rotatable cutting tool is disclosed. The method may comprise fabricating a body of a holder for the cutting tool, wherein the body of the holder extends along an axis and includes a head portion and a shank portion. The head portion may extend from a first end to a second end, and the first end may be configured to receive a cutting tip. The method may further comprise applying a plurality of rotation-assisting strips along an outer surface of the head portion that extend between the first end and the second end. The rotation-assisting strips may project from the outer surface of the head portion. The method may further comprise heat treating the holder having the plurality of rotation-assisting strips.

TECHNICAL FIELD

The present disclosure relates to cutting tools and, more specifically, to rotatable cutting tools with wear resistance and rotation assistance features.

BACKGROUND

Cutting tools may be used for machining or breaking down and degrading structures such as rock, asphalt, paved surfaces, coal, metals, concrete and/or other natural or man-made formations for such applications as mining, road conditioning, and excavating. Examples of such cutting tools include, but are not limited to, asphalt milling picks, drill bits, mining picks, hammers, indenters, shear cutters, indexable cutters, and other engagement tools. For instance, cold planer machines may include a plurality of picks displayed on a drum that rotate to remove a paved surface prior to application of a new paved surface. Cutting tools may include a holder and a cutting tip. The cutting tip may be brazed to the holder and may include a carbide cutting tip.

However, in current cutting tool designs, failure of the holder may occur before the cutting tip is completely worn out. This leads to wasted usable life of the cutting tip and extra owning and operating costs for end-users. The failure of the holder before the cutting tip is completely worn out also reduces replacement interval time, which is not desirable.

U.S. Pat. No. 8,753,755 describes a body, such as a pick tool for cutting coal. The pick tool includes a steel substrate and a hard face structure fused to the steel substrate. The hard face structure includes at least 1 weight percent silicon (Si), at least 5 weight percent chromium (Cr), and at least 40 weight percent tungsten (W). Substantially the balance of the hard face structure includes carbon and an iron group metal M selected from iron (Fe), cobalt (Co), nickel (Ni), and alloy combinations of these elements. The hard face structure includes a plurality of elongate or platelike micro-structures having a mean length of at least 1 micron, a plurality of nano-particles having a mean size of less than 200 nanometers, and a binder material.

In addition, rotatable cutting tools, such as asphalt milling tools and drill bits, may not rotate consistently during use. For example, such cutting tools may slow or stop rotation occasionally during operation. Inconsistent rotation of the cutting tool may cause uneven wear around the circumference of the carbide cutting tip and/or the holder over time. Due to uneven wear, the cutting tool may need to be replaced more frequently, adding to operation costs. In such cases, supporting proper rotation of the cutting tool may be key to promoting even wear around the circumference of the cutting tool and extending the service life of the cutting tool.

U.S. Pat. No. 7,464,993 discloses an attack tool for asphalt milling and mining that includes a base having a shank for attachment to a driving mechanism, and a frustoconical metal carbide segment having a first end bonded to the base and a second end bonded to a second metal carbide segment. In one example, the patent further discloses hard inserts bonded to the base that may aid in rotation of the tool. The inserts may comprise materials such as diamond, cubic boron nitride, and carbides. While effective, there is a need for enhanced designs for rotatable cutting tools that prevent wear of the holder and/or support rotation of the cutting tool to prevent uneven wear of the cutting tool.

SUMMARY

In accordance with one aspect of the present disclosure, a method for fabricating a rotatable cutting tool is disclosed. The method may comprise fabricating a body of a holder of the rotatable cutting tool. The body of the holder may extend along an axis and may include a head portion and a shank portion. The head portion may extend from a first end to a second end. The first end of the head portion may be configured to receive a cutting tip. The method may further comprise applying a plurality of rotation-assisting strips along an outer surface of the head portion that extend between the first end and the second end. The rotation-assisting strips may project from the outer surface of the head portion. The method may further comprise heat treating the holder having the plurality of rotation-assisting strips.

In accordance with another aspect of the present disclosure, a rotatable cutting tool including a holder and a cutting tip is disclosed. The rotatable cutting tool may be fabricated by a method comprising fabricating a body of the holder, wherein the body extends along an axis and includes a head portion and a shank portion. The head portion may extend from a first end to a second end, and the first end of the head portion may be configured to receive the cutting tip. The method may further comprise creating a groove along an outer surface of the head portion proximal to the first end. The groove may extend circumferentially about the head portion. The method may further comprise forming a wear resistant layer in the groove, wherein the wear resistant layer has an outer surface that conforms to an outer surface of the head portion. In addition, the method may further comprise applying a plurality of rotation-assisting strips on the outer surface of the head portion and the outer surface of the wear resistant layer. The rotation-assisting strips may extend between the first end and the second end, and may project from the outer surface of the head portion and the outer surface of the wear resistant layer. The method may further comprise heat treating the holder having the wear resistant layer and the rotation-assisting strips.

In accordance with another aspect of the present disclosure, a rotatable cutting tool is disclosed. The rotatable cutting tool may comprise a holder having a body extending along an axis and including a head portion and a shank portion. The head portion of the holder may extend from a first end to a second end. The rotatable cutting tool may further comprise a wear resistant layer extending circumferentially about the head portion proximal to the first end of the head portion. The wear resistant layer may have an outer surface that conforms to an outer surface of the head portion. In addition, the rotatable cutting tool may comprise a plurality of rotation-assisting strips extending axially along the outer surface of the head portion between the first end and the second end, with the rotation-assisting strips projecting from the outer surface of the head portion. The holder may be heat treated after the application of the wear resistant layer and rotation-assisting strips to the head portion. In addition, the rotatable cutting tool may comprise a cutting tip coupled to the first end of the head portion.

These and other aspects and features of the present disclosure will be more readily understood when read in conjunction with the accompanying drawings.

DETAILED DESCRIPTION

FIG. 1is a perspective view of a cutting tool100, according to one embodiment of the present disclosure. The cutting tool100may be used for machining, breaking into, boring, or degrading structures such as rock, asphalt, coal, metals, or concrete. The cutting tool100may be used in applications including, but not limited to, mining, construction, excavation, and road reconditioning. The cutting tool100may be selected from the group consisting of drill bits, asphalt picks, mining picks, hammers, indenters, shear cutters, indexable cutters, and combinations thereof, without any limitations.

In one example, the cutting tool100may be used in metal working applications, and can be mounted on a machine tool (not shown), such as a milling machine, lathe, or the like. In another example, a number of the cutting tools100may be mounted on a rotatable drum and operated to break up road asphalt, rock formations in coal mining, etc., based on a rotation of the drum.

The cutting tool100may include a holder102. The holder102may include an elongated body103that extends along an axis105. In one example, the holder102may be made of a metal including, but not limited to, steel. For example, the holder102may be made of carbon steel, without limiting the scope of the present disclosure. The body103of the holder102may include a shank portion104. The shank portion104may be generally cylindrical in cross-section, as shown.

A sleeve106of the cutting tool100may surround the shank portion104. The sleeve106allows mounting of the cutting tool100in a socket (not shown) attached to a rotatable member such as the drum. The sleeve106may tightly engage the socket and loosely engage the shank portion104, thereby allowing the cutting tool100to rotate during use. The sleeve106may be slotted and may be made of a resilient material. The sleeve106may extend between an upper flange108and a lower flange110of the holder102. The upper flange108and the lower flange110may have diameters which are greater than that of the socket.

The body103of the holder102may further include a head portion112. The head portion112may be coupled to the shank portion104and may extend between a first end114and a second end116. The head portion112may be generally frustoconical or conical in shape. The head portion112and the shank portion104may be manufactured as a unitary piece. Alternatively, the head portion112and the shank portion104may be manufactured as separate pieces and later assembled to form the holder102. The second end116of the head portion112may be axially separated from the upper flange108by an annular recess120. The annular recess120may permit a user to grasp the cutting tool100with a specialized tool and pull it out of the socket. In alternative arrangements, the cutting tool100may lack the annular recess120.

The first end114of the head portion112may include a cutting tip118. The cutting tip118may have various shapes such as a bullet shaped design. The cutting tip118may be multi-faceted as shown inFIG. 1, or it may be smooth as shown inFIG. 2. For example, the cutting tip118may have a smooth, conical shape (seeFIG. 2) or a circular shape. The cutting tip118may be coupled to the first end114of the head portion112. In one example, the cutting tip118may be cemented or brazed to the head portion112into a cavity130(seeFIG. 3) formed at the first end114. Alternatively, any known coupling process may be used to couple the cutting tip118with the head portion112, without any limitations. In one example, the cutting tip118may be made of a wear resistant material, such as carbide. For example, the cutting tip118may be made of a cemented tungsten carbide. In alternative examples, the cutting tip118may include a material such as polycrystalline diamond.

Referring toFIG. 3, the head portion112of the holder102may include a groove126. The groove126may be created in the holder102proximal to the first end114of the head portion112that receives the cutting tool tip118. In one example, the groove126may be created by a metal removing process, such as machining In another example, the groove126may be created in the holder102during the manufacturing of the holder102. For example, the groove126may be created during molding or casting of the holder102. In yet another example, the groove126may be created during a forging process.

The groove126may extend circumferentially about the head portion112of the holder102. The groove126may include a shape that corresponds to a wear pattern of the head portion112. In one example, the groove126may include a concave arcuate cross-sectional configuration. In another example, the groove126may include a conic undercut. However, in other embodiments, the shape of the groove126may vary. For example, the groove126may include a rectangular cross-sectional configuration, a semi-circular cross-sectional configuration, a trapezoid cross-sectional configuration, and the like, without limiting the scope of the present disclosure. For instance, as shown inFIG. 4, the groove126may be longer in the axial direction and optionally deeper near the first end114.

The holder102of the cutting tool100may be subject to wear and tear during operation of the cutting tool100. More particularly, a portion122(seeFIGS. 1 and 2) of the head portion112of the holder102proximal to the first end114may be subject to wear that may cause premature failure of the holder102. The wear experienced at the first end114may cause reduction in dimensions at the head portion112of the holder102.

In order to mitigate the failure of the holder102due to wear, the head portion112of the holder102may be selectively hardfaced by providing one or more wear resistant layers124. Referring toFIG. 5, the wear resistant layer124may be proximal to the first end114of the head portion112. In some examples, the wear resistant layer124may be provided on an outer surface128of the head portion112, and may extend axially from an upper periphery134defined by an upper surface132. The upper surface132may be defined at the head portion112of the holder102. The wear resistant layer124may be formed within the groove126of the head portion112(seeFIG. 5). The wear resistant layer124may conform to the outer surface128of the holder102. For instance, the wear resistant layer124may have an outer surface135that is flush with the outer surface128of the holder102(seeFIG. 5). The wear resistant layer124may be formed by applying a wear resistant material in the groove126. In one example, the wear resistant material may be cladded within the groove126of the holder102. In some arrangements, such as with a deeper conic undercut (seeFIG. 4), two or more layers of wear resistant material may be applied in the groove126to form the wear resistant layer124. In addition, in alternative arrangements, the wear resistant layer124may be below the outer surface128of the head portion112as shown inFIG. 7to permit exposure of the wear resistant layer124as the outer surface128of the head portion112wears away faster than the wear resistant layer124. Alternatively, the wear resistant layer124may be above or project from the outer surface128of the head portion112as shown inFIG. 8. Alternatives such as these, and combinations thereof, also fall within the scope of the present disclosure.

The wear resistant material may be cladded within the groove126created on the outer surface128of the holder102. The wear resistant material may include a hard particle material, or a matrix of a hard particle material and a metal. Further, the wear resistant material may include a hard particle precipitating material, or a matrix of a hard particle precipitation material and a metal. In some examples, the wear resistant material includes a carbide, a boride, and/or cermet. In one example, the wear resistant material includes a carbide former or boride former. In another example, the wear resistant material includes a solid state carbide or a solid state boride. It should be noted that the wear resistant material may include any composition that resists wear during operation of the cutting tool100.

It should be noted that the wear resistant material may be chosen based on the operation that the cutting tool100performs and also the amount of stress or wear on the head portion112during operation. Further, a dimension of the groove126(and the wear resistant layer124) may vary based on an amount of stress or wear on the head portion112, or a dimension of the cutting tool100.

In one example, a laser cladding process may be used to provide the wear resistant layer124in the groove126. The laser cladding process may include any one or both of a powder laser cladding process or a wired laser cladding process. Further, the wear resistant material can be provided in the groove126by a metal deposition process or a metal spraying process. Any one of a thermal spray coating process, a vapor deposition process, or a chemical vapor deposition process may be used to provide the wear resistant material in the groove126. Alternatively, any known method may be employed to clad the wear resistant material in the groove126.

FIG. 8is a perspective view of the cutting tool100having the wear resistant layer124. In the illustrated example, the wear resistant layer124has a length “L” measured in an axial direction. It should be noted that the length “L” of the wear resistant layer124depicted in the accompanying figure is exemplary in nature. In some examples, the length “L” of the wear resistant layer124may be greater than or equal to one half of an overall axial length “l1” of the head portion112of the holder102, without limiting the scope of the present disclosure.

Further, the wear resistant layer124may be located at a distance “D” measured in an axial direction from the upper surface132of the head portion112of the holder102. In an example where the groove126is embodied as the conic undercut, the wear resistant layer124may extend axially from the upper periphery134defined by the upper surface132. In such an example, the distance “D” may be approximately equal to zero. It should be noted that the length “L” and the distance “D” may be optimally selected in order to effectively mitigate wear of the holder102. The length “L” and the distance “D” may be varied based on operational requirements. Alternatively, the wear resistant layer124may also be applied to the upper surface132as shown inFIG. 9. As yet another possibility, the wear resistant layer124may be applied only to the upper surface132as shown inFIG. 10. For example, application of the wear resistant layer124to the upper surface132may be carried out before the cutting tip118is coupled to the first end114of the holder102.

Referring now toFIGS. 11-13, the cutting tool100may include one or more rotation-assisting strips140applied to the outer surface128of the head portion112. The rotation-assisting strips140may project from the outer surface128of the head portion112, and may act as fins or ribs that assist in propelling the cutting tool100as it is drilling or boring into a structure (seeFIG. 13). As such, the strips140may promote rotation of the cutting tool100, thereby preventing uneven wear about the circumference of the cutting tip118and/or the holder102. By reducing uneven wear of the cutting tool100, the rotation-assisting strips140may advantageously extend the service life of the cutting tool100.

The rotation-assisting strips140may extend from the first end114(e.g., from the upper periphery134) to the second end116along the outer surface128of the head portion112with each of the strips140having a length (l2) that is equal to a length (l3) of the head portion112(seeFIG. 11). If the cutting tool100includes the annular recess120, the second end116of the head portion112may be disposed above the annular recess120such that the strips140terminate above the annular recess120(seeFIG. 11). If the cutting tool100lacks the annular recess120as shown inFIG. 12, the second end116of the head portion112may be disposed above the upper flange108such that the strips140terminate above the upper flange108. Alternatively, the length (l2) of the strips140may be less than the length (l3) of the outer surface128such that the strips140extend somewhere between the first end114and the second end116. As yet another possibility, the strips140may have variable lengths (l2) with some of the strips140being longer than others.

Furthermore, in some arrangements, the cutting tool100may have at least four or at least five of the rotation-assisting strips140. In other arrangements, the cutting tool100may have any number of the rotation-assisting strips140. In addition, as shown inFIG. 13, the strips140may be equally spaced about the circumference of the head portion112. Alternatively, the strips140may be unevenly spaced or asymmetrically distributed about the circumference of the head portion112. Moreover, each of the strips140may have a width (w) and a height (h) (seeFIG. 13). The widths (w) of the strips140may be greater than the heights (h) of the strips140. Alternatively, the widths (w) of the strips140may be equal to or less than the heights (h) of the strips140. In any event, each of the strips140may project from the outer surface128of the head portion112by a distance that is equal to the height (h) of the strip140(seeFIG. 13). For example, the heights (h) of the strips140may range from about 0.1 millimeters (mm) to about 10 mm, although the heights may deviate substantially from this range depending on the dimensions of the cutting tool100.

The strips140may extend linearly along the outer surface128in a direction corresponding to the axis105, as shown inFIGS. 11-12. Such an arrangement may support rotation of the tool100regardless of the direction of rotation (clockwise or counterclockwise) of the tool100in use. Alternatively, the strips140may be angled or curved with respect to the axis105in a helical pattern as shown inFIG. 14. The helical pattern of the strips140may have a right-handed twist (as shown) or a left-handed twist depending on the direction of rotation of the cutting tool100during use. Specifically, the twist (right-handed or left-handed) of the helical pattern may correspond to the direction of rotation (counterclockwise or clockwise) of the cutting tool100in use.

The rotation-assisting strips140may be separate from each other as shown inFIGS. 11-14. Alternatively, as shown inFIG. 15, the number and/or widths (w) of the rotation-assisting strips140may be great enough such that the strips140join or coalesce at the first end114of the head portion112. As yet another possibility, the widths (w) of the strips140may vary along their lengths (l2). For instance, as shown inFIG. 16, the strips140may be narrower at the first end114and may become progressively wider as they reach the second end116. Likewise, in other arrangements, the strips140may be wider at the first end114and may become narrower as they approach the second end116. Variations such as these, as well as combinations of the aforementioned arrangements, also fall within the scope of the present disclosure.

If the head portion112lacks the groove126and the wear resistant layer124, the strips140may be applied only to the outer surface128of the head portion112as shown inFIG. 17. Alternatively, if the head portion112includes the groove126and the wear resistant layer124, the strips140may be applied on at least a portion of both the outer surface128of the head portion112and the outer surface135of the wear resistant layer124(seeFIG. 18). For example, as shown inFIG. 18, the strips140may be applied along the entire length (l3) of the outer surface128including the outer surface135of the wear resistant layer124with the strips140projecting from both of the outer surfaces128and135(also seeFIGS. 11 and 13). As yet another possibility, if the head portion112includes the wear resistant layer124, the strips140may be applied only on the outer surface128of the head portion112, as shown inFIG. 19. For example, if the wear resistant layer124is proximal to the first end114, the strips140may be applied along the outer surface128between the wear resistant layer124and the second end116of the head portion112without contacting the wear resistant layer124(seeFIG. 19). In other arrangements, the strips140may only be applied on the wear resistant layer124and not along the outer surface128of the head portion112. Variations such as these, as well as combinations thereof, also fall within the scope of the present disclosure.

Turning toFIG. 20, in an alternative arrangement, the rotation-assisting strips140may be applied or deposited within grooves150formed vertically along the outer surface128of the head portion112. In this regard, the number of grooves150formed in the head portion112may correspond to the number of strips140. The grooves150may extend along the entire length (l3) of the head portion112, or somewhere between the first end114and the second end116of the head portion112. As with the circumferential groove126, the grooves150may be formed in the head portion112by a metal removal process, such as machining, or during the manufacture of the holder102, such as by molding, casting, or forging. In alternative designs, the grooves150may have a helical pattern to support helical strips (seeFIG. 14) or they may have widths that vary along the length (l3) of the head portion112(seeFIG. 16). The strips140applied within the grooves150may project from the outer surface128of the head portion112as shown inFIG. 20. Alternatively, the strips140may be flush with the outer surface128(seeFIG. 21), or the strips140may be below the outer surface128(seeFIG. 22). In the latter configurations, wearing away of the of the metal material of the head portion112may allow the strips140to become exposed and provide ribs that assist the rotation of the cutting tool100through the life of the tool100. Exposure of the strips140may occur with use as the material of the holder102may wear away faster than the strips140. Variations such as these, as well as combinations of the aforementioned arrangements, also fall within the scope of the present disclosure.

The rotation-assisting strips140may be formed from a wear resistant material. The wear resistant material of the strips140may include a precipitation hardening material, a hard particle material, or a matrix of a hard particle material and a metal. For example, the hard particle material may include a carbide, a boride, a cermet, a carbide former, a boride former, or combinations thereof. The strips140may be formed from the same wear resistant material as the wear resistant material of the wear resistant layer124, although the strips140and the wear resistant layer124may be formed from different materials as well. Alternatively, the strips140may be formed from a metal, a metal alloy, a metal matrix composite material, other types of composite materials, and combinations thereof.

A laser cladding process may be used to apply the rotation-assisting strips140to the head portion112, either directly to the outer surface128or within the grooves150. Specifically, either or both of powder laser cladding and wire laser cladding may be used to deposit the strips140on the outer surface128(and/or on the outer surface135of the wear resistant layer124) as will be understood by those with ordinary skill in the art. Alternatively, the strips140may be applied to the head portion112using another deposition technique apparent to those skilled in the art such as, but not limited to, welding, brazing, electroplating, thermal spray coating, or chemical vapor deposition.

Application of the strips140and/or the wear resistant layer124to the head portion112by the aforementioned methods may expose the holder102to heat which may soften and alter the microstructure of the metal material of the holder102. Thus, the holder102may be heat treated after application of the strips140and/or the wear resistant layer124to harden material of the holder102. The holder102may be heat treated either before or after the cutting tip118is coupled to the head portion112of the holder102. The heat treatment process may include any one or a combination of heat treatment processes apparent to those skilled in the art such as, but not limited to, annealing, case hardening, precipitation hardening, tempering, normalizing, quench hardening, and combinations thereof.

INDUSTRIAL APPLICABILITY

In general, the teachings of the present disclosure may find applicability in many industries including, but not limited to, mining, road construction, construction, and excavation. More specifically, the present disclosure may find applicability in any industry using rotatable cutting tools that are subject to wear with use and/or uneven wear caused by poor or inconsistent rotation of the cutting tool.

Referring toFIG. 23, a flowchart of a method200of selectively hardfacing the holder102the cutting tool100is shown. Beginning at a block202, the groove126may be created on the outer surface128of the holder102. The groove126may be created proximal to the first end114of the head portion112that receives the cutting tip118(seeFIG. 3). The groove126may extend circumferentially about the head portion112of the holder02. The groove126may include a concave arcuate cross-sectional configuration or a conic undercut, as well as various other possible shapes. At a block204, a wear resistant material may be applied within the groove126of the holder102to form the wear resistant layer124. The step of applying the wear resistant material may include laser cladding the wear resistant material within the groove126of the holder102. The wear resistant material may include one of a hard particle precipitating material, or a matrix of a hard particle precipitating material and a metal. In one example, the wear resistant may include at least one of a carbide, a boride, and/or a cermet. At a block206, the holder102having the wear resistant layer124may be heat treated. Further, the cutting tip118may be coupled to the head portion112of the holder102prior to the heat treatment. In another example, the cutting tip118may be coupled to the head portion112after the heat treatment.

Turning now toFIG. 24, a method210that may be used to fabricate the cutting tool100with the rotation-assisting strips140is shown. Beginning at a first block212, the body103of the holder102may be fabricated. For example, the block212may involve forging or casting the head portion112and the shank portion104as a unitary piece. Alternatively, the head portion112and the shank portion104may be fabricated separately and later assembled to form the holder102. According to a next block214, the rotation-assisting strips140may be applied to the outer surface128(or within the grooves150) of the head portion112by laser cladding or another deposition process. The rotation-assisting strips140may be applied as linear lines that extend axially along the outer surface128of the head portion112between the first end114and the second end116(see, for example,FIGS. 11-12). Alternatively, the strips140may be applied to the outer surface128as angled or curved lines in a helical pattern (seeFIG. 14).

As the application of the strips140to the head portion112may expose the holder to heat and cause the metal material of the holder102to soften, the holder102may be heat treated after the strips140are applied according to a next block218to harden the metal material of the holder102. Optionally, the cutting tip118may be coupled (e.g., brazed, cemented, etc.) to the first end114of the head portion112according to a block216prior to the block218. Alternatively, the block216may be carried out after the heat treatment.

Turning now toFIG. 25, a method220that may be used to fabricate the cutting tool100having both the wear resistant layer124and the rotation-assisting strips140is shown. At a first block222, the body103of the holder102including the head portion112and the shaft portion104may be fabricated. The block222may involve forging or casting the head portion112and the shank portion104as a unitary piece, or it may involve forging or casting the head portion112and the shank portion104as separate units and assembling the units together. According to a next block224, the groove126may be created along the outer surface128of the head portion112of the holder102. For example, the block224may involve machining the groove126into the head portion112proximal to the first end114(seeFIG. 3). Alternatively, the groove126may be forged or cast as a feature of the holder102during the block222. The wear resistant layer124may then be formed in the groove126according to a next block226. The block226may involve applying the wear resistant layer124in the groove126by laser cladding or another deposition process.

The rotation-assisting strips140may be applied to the head portion112according to a block228. Specifically, the strips140may be deposited on either or both of the outer surface128of the head portion112and the outer surface135of the wear resistant layer124as explained above. Deposition of the strips140on the head portion112may be carried out using a laser cladding process or another deposition method apparent to those skilled in the art. If the strips140are only be applied on the outer surface128of the head portion112(seeFIG. 13), the blocks226and228may be carried out in any order.

The holder102may then be heat treated following the blocks226and228according to a block232. Heat treatment of the holder102in this way may harden and toughen the metal material of the holder102, thereby compensating for at least some of the loss in hardness resulting from the application of the wear resistant layer124and the rotation-assisting strips140to the holder102. Optionally, the cutting tip118may be coupled (e.g., brazed, cemented, etc.) to the first end114of the holder102prior to the block232. Alternatively, the cutting tip118may be coupled to the first end114of the holder102after the block232to provide the cutting tool100.

As disclosed herein, the rotatable cutting tool may include a cutting tip and a holder including a shank portion and a head portion supporting the cutting tip. The cutting tool may be selectively hardfaced by applying a wear resistant layer to a portion of the head portion of the holder that is subject to wear. Specifically, a groove may be formed at the portion of the head portion that is susceptible to wear during use, and a wear resistant material may be applied within the groove to form the wear resistant layer. The wear resistant layer may not alter the overall geometry and design of the holder as it may conform to the shape of the outer surface of the head portion. Thus, the present disclosure provides a cost-effective solution to improve the wear resistance of the cutting tool without disrupting the original geometry of the cutting tool. Specifically, by selectively hardfacing the holder of the cutting tool, a retention time of the cutting tool may be increased. Further, the wear resistant layer may reduce the possibility of failure of the holder due to wear and tear, thereby allowing customers to increase replacement interval time. The wear resistant layer also increases the useful life of the holder and reduces owning and operating costs for the customers.

Alternatively, or in combination with this, the rotatable cutting tool may include rotation-assisting strips presented on the head portion that improve the rotation of the cutting tool as it is drilling or boring into a structure. By promoting rotation of the tool, the strips may prevent uneven wear around the circumference of the cutting tool as is seen in some prior art cutting tools that lack such rotation assistance features. Accordingly, the strips provide an additional cost-effective approach to extend the service life of the cutting tool and reduce the need for replacement of the tool with extended use.