JP2678410B2 - Method of manufacturing chuck gripping part of rotary work tool - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a gripping portion of a chuck in a rotary work tool such as a drill bit or a driver bit.

[0002]

2. Description of the Related Art In conventional rotary work tools such as a drill bit and a driver bit, in addition to those in which the grip of the shank chuck is straight like an ironworking drill, it is also like a woodworking drill or a screwdriver. In the case of applying a large rotational force to the bit, the shank has a non-slip grip portion so that the chuck does not slip.

When the shank is formed, the above-mentioned gripping part is separately machined with the shank, the bit body and the gripping body are separately formed, and the shank of the bit body is fitted to the gripping body. Together, they are brazed, locked with a stop pin, or with a knurled shank, pushed into the shaft hole of the gripper and gripped by applying external pressure from the outside of the gripper. and those fastened by deforming the portion Shrinkage hand gripping member to the other shank
It was fastened by steps .

[0004]

In the conventional rotary work tool described above, when the bit portion in which the bit portion and the grip portion are integrally formed has a diameter smaller than that of the grip portion, gripping is performed. The steel bar, which is the material for forming the holding part, has the thickness of the holding part as the thickness of the holding part, and the cross-sectional shape is the cross-sectional shape of the holding part. The profile material is uneconomical with poor yield because the bit portion is machined while producing a large amount of shavings.

Since it is technically difficult to automate the manufacturing of the gripping part of the chuck of the bit, the gripping part is formed manually after the bit part is formed. Machining failure is likely to occur, and if the machining failure occurs, the bent bit material is wasted, so that the machining work requires carefulness, which hinders improvement in work efficiency.

In various bits, the integral formation of the bit portion and the holding portion is troublesome as described above. Therefore, as another means, it is possible to combine a holding body and a bit body separately formed. It considered, but in means to fix the gripping portion to the bit body, a result of attempting the implementation of which the shaft hole of the brazing, the fixing in stop pin, grip body bit body marked with knurled shank If the bit body and the grip body are forcibly fitted and deformed by applying external pressure to the grip body to strengthen the engagement between the bit body and the grip body, the axes of the bit body and the grip body are misaligned and it is difficult to match them. , When rotated for use, the bit will run out with inaccurate core accuracy, and especially in the case of fixing with a stop pin, the pin will loosen easily and rattling will occur between the gripping body and the bit body. The stopper pin comes off and the bit body flies from the holding body. Out had been adversely harm to the other.

Also in the shrink-fitting means, since the size of the bit is small, it is extremely difficult to adjust the heating of the gripping body, which easily overheats and becomes red-heated, and the purpose cannot be achieved. Since the holding body does not expand and shrink fit is not possible,
Shrink-fitting means is not suitable for small things such as bits, and the means for assembling the bit body and the grip body separately formed has failed.

Further, in the above-mentioned conventional bit processing means having a grip portion, in which the grip portion is integrally formed of a single material after the formation of the bit portion, the bit portion is formed. This is a system of work for forming the gripping part following processing, which can be mass-produced by an automated machine for forming the bit part, but the next gripping part is formed. Mass production is not possible due to manual work, making mass production impossible as a whole, and if there is a failure in the gripping part forming process in the second stage, one bit material will be lost.

The present invention is an invention relating to a method of manufacturing a rotary work tool which solves the problems of the above-mentioned conventional ones.

[0010]

In order to achieve the above-mentioned object, the present invention forms a gripping body for engaging with a rotary work tool and a chuck separately, and then grips the rotary work tool at a shaft tip portion of a main shaft thereof. be those strongly engaging the bearing member, more particularly, to grab the shaft tip portion 1 ₂ of the spindle 1 ₁ of the rotary tool 1 such as a drill bit or screwdriver bit that rotates the chuck of the electric drill motor Shaft engaging hole 2 of grip body 2
And pressed into _1, shaft tip portion 1 with forcibly fitted align the gripping member 2 to _2, shaft tip portion 1 ₂ at high temperature frictional heat generated by rubbing between the shaft tip portion 1 ₂ and gripping member 2 the outer peripheral surface and the gripping member 2 of the shaft engaging hole 2 ₁ a hole wall surface and the grip member 2 by thermal fusion of those to firmly fastened to the main shaft 1 _1.

[0011] shaft tip portion 1 ₂ of the spindle 1 is tapered tapered, moreover column placed in or on the ground without its outer peripheral surface which is rough, closely spaced towards the very thin small ridges 1 ₃ a longitudinal axis It is a group of small ridges.

[0012] gripping member 2 to be installed on the shaft tip portion 1 ₂ of the spindle 1 _1, the horizontal longitudinal plan consists profile of square cross-section and hexagonal cross-section, the shaft tip portion 1 ₂ fits shaft engaging hole 2 ₁ is a tapered tapered bore tapered and became tapered shaft tip portion 1 ₂ and symmetrical, the hole wall or a rough satin-like, or, very thin small in pore walls Ridge 2
₁₁ is a group of small ridges arranged in a row at a narrow interval toward the hole bottom direction.

Then, the shaft engaging hole 2 ₁ of the grip body 2 described above.
Within forcibly fitting while rotating the shaft tip portion 1 ₂ of the spindle 1 _1, that the main shaft 1 ₁ is rotated, the inner wall surface of the shaft engaging hole 2 ₁ a shaft tip portion 1 ₂ and gripping member 2 the high temperature frictional heat generated by contact with, in which shaft tip portion 1 ₂ can be fastened by heat sealing to the gripping member 2.

[0014] Methods of attaching a gripping member 2 to the main shaft 1 ₁ is a machine frame, at propeller shaft of can rotate being connected to the power 4, moreover, promoting axis movement backward and forward in the axial direction A support base that is supported by a shaft base that is supported as possible, and that also supports the support part of the gripping body 2 facing the shaft end face and the end face of the propulsion shaft on the machine frame facing this. installing the propeller shaft of the joining machine provided on the machine frame, a main shaft 1 ₁ of the tool 1 shaft tip portion 1 ₂ is to face the end surface of the支受portion of the gripping member 2 to支受the gripping member 2 while, in the支受portion after the gripping member 2 is the axial engaging hole 2 ₁ opening was placed so as to face-to-face with the end face of the shaft tip portion 1 _2, the propeller shaft is rotated by the power spindle 1
While rotating the _1, in which fitted bearing base of the shaft tip portion 1 ₂ is advanced towards the gripping member 2 to force while pushing the shaft engaging hole 2 ₁ gripping body 2.

Furthermore order to make stronger the engagement of the, in mating operation of gripping member 2 of the main shaft 1 _1, and the outer peripheral surface of the shaft tip portion 1 ₂ of the spindle 1 _1, chucking gripping member 2 the shaft engaging hole 2 ₁ a hole wall surface in contact with the high temperature both by frictional heat shaft tip portion 1 ₂ of the chucking gripping member 2
By heat-sealing, it is possible to further strengthen the fastening.

[0016]

[Operation] When drilling or tightening or loosening screws using the rotary work tool 1 such as a drill bit or a driver bit, the spindle is attached to the chuck of the drive shaft of a powerful rotary machine such as an electric drill machine or an air drill machine. It is engaged to perform drilling and tightening and loosening of screws with a strong torque.

The most general type of engagement between the chuck and the main shaft is a direct shank called a straight shank in which the main shaft having a circular cross section is engaged with the chuck and is gripped by the jaws of the chuck.

However, when the main shaft is directly gripped by the chuck as described above, when a large load is applied to the tool, the jaws of the chuck slip and become useless. It will cause shaving damage.

For this reason, a gripping portion made of a deformed material having a polygonal cross section such as a quadrangular cross section or a hexagonal cross section is engaged with the spindle 1 at the tip of the shaft where the chuck grips the spindle 1. However, it is integrated with the main shaft so that the engagement between the main shaft of the bit and the chuck is more complete, but this has a problem in that the gripping part is fixed to the main shaft as described above.

According to the present invention, the bit body of the rotary work tool and the grip body of the chuck are separately formed of steel materials suitable for the respective purposes, and then the grip body of the chuck is attached to the bit body. Even if the main body has the same shape, a gripping body suitable for the chuck can be installed and the chuck can surely grip the gripping body even if the main body has the same shape.

When the gripping of the gripping body is repeated by the chuck, the gripping body is abraded and the engagement state between the chuck and the gripping body is deteriorated by the conventional rotary work tool. The phenomenon is because the gripping body is soft,
As in the present invention, a material obtained by forming the grip body 2 and durable material that is different abrasion resistance of the bit body and keep engaged with the shaft tip portion 1 ₂ of the body, repeated chuck It is able to withstand the grasping of.

[0022] In the engagement of the shaft tip portion 1 ₂ of the gripping member 2 and the main shaft 1, and the tapered holes tapering the shaft engaging hole 2 ₁ a gripping member 2, also, the shaft tip portion 1 _2, the left in the same tapered tapered shaft and Jikugakarigoana 2 ₁ Depa hole, the engagement of the shaft tip portion 1 ₂ of the gripping member 2 to one positive確且reliable, yet firm You can

Further, the shaft tip portion 1 ₂ the outer peripheral surface and the shaft engaging hole 2 ₁ a hole wall surface of the gripping member 2, or respectively rough coarse satin 1 ₅ and 2 ₁₂ sides, shaft tip portion 1 ₂ of the outer peripheral surface and the shaft engaging hole 2 ₁ a hole wall of the gripping member 2 and the small protrusion 2 ₁₁ small ridges 1 ₃ of the groups that were subjected respectively, Jikugakarigoana 2 ₁
When the shaft tip portion 1 ₂ is press-fitted while rotating, in the contact surface, that the frictional heat of high temperature due to contact therebetween occurs from the friction coefficient therebetween is large, the shaft tip portion 1 ₂ and the chuck gripping The body 2 has a temperature at which heat fusion can be performed.

The group of the group and the small protrusion 1 ₃ small protrusion 2 ₁₁ heated to high temperature, which can heat-sealed by heat generation, soften deformation is facilitated and shaft tip portion 1 to Jikugakarigoana 2 ₁ When ₂ is pressed, Jikugakarigoana 2 while the group of the main shaft 1 ₁ of the small protrusion 1 ₃ interlace a group of axial engagement hole 2 ₁ a hole wall of thin small protrusion 2 ₁₁
Deepen overlap between the _first sub protrusion _{1 3} group and the shaft tip portion _{1 2} of the small protrusion _{2 11.}

[0025] When the Jikugakarigoana ₂ shaft tip portion _{1 2} in ₁ has been accommodated, stopping the pushing operation of the shaft tip portion _{1 2} to Jikugakarigoana _{2 1,} and the group of small protrusion _{2 11} Small ridge 1 ₃
The small ridges 2 that all mesh with the group of
₁₁ and the small protrusion _{1 3} heat-sealed to the small protrusion _{1 3} small protrusion _{2 11,} gripping member 2 is firmly fastened to the shaft tip portion _{1 2,} gripping the spindle _{1 1} Body 2 never comes off.

[0026] and the outer peripheral surface of the spindle 1 ₁ of the shaft tip portion 1 _2, the shaft engagement hole 2 ₁ a hole wall surface of the gripping member 2, coarse pear 1 ₅ gritty without land shaped respectively to 2 ₁₂ sides What you did,
And contacts pushed while rotating the shaft tip portion 1 ₂ to gripping member 2 of the shaft engaging hole 2 ₁ a high temperature frictional heat occurs rub against, gripping member 2 is heat the shaft tip portion 1 ₂ Can be dressed.

A rotary work tool such as a drill bit or a driver bit has two systems, that is, a process of forming a bit body and a process of forming a gripping body of a chuck. It is manufactured by the process of engaging the gripping body of the chuck with the body and finishing the rotary work tool.

[0028] The bit body, the suits steel for the purpose of the work, research cutting means and so as to form the鍜造means, and the outer peripheral surface of the shaft tip portion 1 _2, shaft tip of the main shaft 1 ₁ to gripping member 2 a tapered hole wall of the shaft engaging hole 2 ₁ a converging section 1 ₂ fits, respectively, the processing of the surface so that the surface of the rough coarse satin.

[0029]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the accompanying drawings of a woodworking drill.

Although a woodworking drill is shown as an example in the drawings, in addition to this, if it is a rotary working tool such as an ironworking drill, a driver bit, a reamer, or a grindstone with a rotary shaft, it is limited to the example. It is not something that will be done.

The woodworking drill of the present invention will be described with reference to the front view of FIG. 1 and the conventional woodworking drill with the front view of FIG.

In the conventional woodworking drill, as can be seen from FIG. 2, the bit body and the gripping body of the chuck are integrally formed from the same steel material.

The woodworking drill is a rotary power tool 1 of the present invention to this, and the bit body 1 ₄ and gripping member 2 is separately formed in different steel respectively, of the main shaft 1 ₁ of the bit body 1 ₄ the shaft tip portion 1 _2, the shaft engagement hole of the grip member 2 of the chuck 2 forcibly fitted pushing a strong force in the _1, moreover, the gripping member 2 is heat-sealed to the shaft tip portion 1 ₂ It will be.

The spindle 1 ₁ following the bit body 1 _4, shaft tip portion 1 ₂ are tapered tapered, moreover, on the outer peripheral surface of this portion, an annular toward the axial direction of the main shaft 1 ₁ by being provided by従列a very thin small protrusion 1 ₃ closely spaced, gritty, it is obtained by the rough surface of serrated form.

The gripping body 2 of the chuck of an electric drill machine or an air drill machine is formed by cutting a hexagonal drawn steel material into a predetermined size, as can be seen from FIG.

[0036] Then, the gripping member 2 of the chuck, as well bored a shaft engaging hole 2 ₁ tapered tapering central portion, towards the bottom of the hole to the hole wall surface of Jikugakarigoana 2 ₁ Te provided by従列at narrow intervals of very fine small protrusion 2 ₁₁ group of cyclic, gritty, is obtained by the rough surface of serrated form.

Further, as another example of the above embodiment, as shown in Figure 7, the tapered outer peripheral surface of the tapered shaft tip portion 1 _2, the gripping member 2, a tapered shape with a tapered a hole wall surface of the shaft engaging hole 2 ₁ a, respectively, gritty,
It may be a rough surface of the plain materials ₁₅ and 2 ₁₂ .

The gripping body 2 has a hexagonal cross section in the embodiment, but in addition to this, a plurality of square pillars, quadrangular pyramid trapezoids, and two, three, six or the like are provided on the outer peripheral surface of the cylinder. It may have a ridge or a concave groove, but the point is that it corresponds to the chuck of the electric drill machine or the air drill machine, and is limited to the embodiment as long as it can be accurately and surely engaged with the chuck. is not.

[0039] The operation of fastening the gripping member 2 in the axial distal end portion 1 ₂ of the spindle 1 _1, while in the first embodiment rotates the bit body 1, the shaft tip portion 1 ₂ of the gripping member 2 axes Engagement hole 2
By pushing in _one, the small protrusion 1 ₃ of the outer peripheral surface of the shaft tip portion 1 ₂ by frictional heat generated on the contact surface, Jikugakarigoana 2 ₁
The small protrusion 2 _11, together with the small protrusion 1 ₃ engage both by allowing skipped small protrusion 2 _11, and the strong tapering engagement heat sealed.

The second embodiment of fastening the gripping member 2 in the axial distal end portion 1 ₂ of the spindle 1 _1, while the rough surface of pear 1 ₅ gritty the outer peripheral surface of the shaft tip portion 1 _2, Gripping body 2
Axis engagement hole 2 ₁ a hole wall surfaces that have a rough surface of pear gritty land 2 _12, shaft tip portion 1 ₂ Jikugakarigoana 2 within ₁
There when rubbed into the hole wall, thus generating high-temperature frictional heat at the contact surface, it can be to a temperature that allows thermal fusion satin 1 ₅ and no land 2 _12, a first embodiment Similarly, it is possible to a strong fastening with both a gripping body 2 and Jikusaki portions 1 ₂ that engages the shaft tip portion 1 ₂ is thermally deposited on the contact surface.

[0041] Incidentally, means for generating a high temperature frictional heat for thermally fusing the gripping member 2 in the axial tip portion 1 _2, the contact surfaces such that above a respective strip-like surface and satin-like surface and although addition may contact surface in addition to this and the like also have a large coefficient of friction, in short by the contact between the shaft engaging hole 2 ₁ a shaft tip portion 1 ₂ and gripping member 2 of the high-temperature The present invention is not limited to the embodiment as long as the frictional heat is easily generated.

[0042] the main shaft 1 ₁ of the rotary tool 1 such as a drill bit or a screwdriver bit, the production method of the present invention to provide a gripping member 2 for chuck grip it, having no bit body in advance gripping portion and forming, and formed so that the shaft tip portion 1 ₂ of the spindle 1 is tapered tapered, rough ground surface as the shaft distal end portion 1 a small protrusion on the outer peripheral surface of the ₂ 1 ₃ Yanashi locations 1 ₅ Forming process.

The hexagonal cross-section, the central portion of the one axial end surface, the tapered shaft tip portion 1 that tapers of the main shaft 1 _1
2 is engaged, tapered became tapered shaft engaging hole 2 ₁
As well as bored, small protrusion in the hole wall of Jikugakarigoana 2 ₁ 2
By adding the group of ₁₁ or the plain land 2 ₁₂ ,
Material processing steps and the hole wall to form a tapered shaft engaging hole 2 ₁ became rough surface which is rough.

Next, the bonding machine used in the step for installing the gripping member 2 to the main shaft 1 ₁ of the rotary working tool 1 is in its machine frame,支受portion for支受the gripping member 2 A support base having a support shaft and a headstock having a propulsion shaft for supporting the rotary work tool 1 such that the support portion of the support base and the propulsion shaft of the headstock are opposed to each other on the machine frame. The support base is fixedly fixed to the machine frame, and the headstock is slidably installed on the machine frame so that it can approach and separate from the support base on the machine frame. In addition to being rotatably supported by the shaft, it is rotated by the power provided on the headstock, and the propulsion shaft has a chuck for gripping the rotary work tool at the end of the shaft on the side facing the gripping body of the support base. is there.

The next support table支受portion of the bonding machine for above, the gripping member 2 of the rotary tool 1 Jikugakarigoana 2 _1, installed to face the bearing base of the propeller shaft chuck and the propulsion axis chuck, spindle 1 ₁ of the rotary tool 1, shaft tip portion 1 ₂ of the spindle 1 ₁ is allowed to set up to face the shaft engaging hole 2 ₁ a gripping member 2, The propulsion shaft is rotated by the power, and the rotary work tool 1 for the propulsion shaft is rotated.
Furthermore, to move the bearing base that支受the propeller shaft to the support base side, the shaft tip portion 1 ₂ of the spindle 1 ₁ of the rotary tool 1 is rotating, and is支受to the support gripping a step of press-fitting in the shaft engagement hole 2 ₁ body 2.

[0046] by a process of press-fitting the shaft tip portion _{1 2} of the above Jikugakarigoana _{2 1,} shaft tip portion _{1 2} and Jikugakarigoana _{2 1}
Shaft tip part with a large friction coefficient at the contact part 1 ₂
Rotating the gripping member 2 in the axial distal end portion 1 ₂ by heating with an outer peripheral surface and the Jikugakarigoana 2 ₁ of the hole wall surface rubbed at the contact surface becomes hot and a step of the fastening by thermal fusion The gripping body 2 can be installed on the work tool 1.

[0047] Particularly shaft tip portion _{1 2} of the outer peripheral surface to the small protrusion _{1 3}
To that denoted by the engagement between those denoted by the small protrusion 2 ₁₁ axially engaging hole 2 ₁ a hole wall surface of the gripping member 2, when this generates heat rub against small impact and a high temperature Article 1 ₃ and the small protrusion ₂₁₁ is soft for high heat, easily deformed further pushing force is applied, the shaft tip portion 1 ₂ is pressed into Jikugakarigoana 2 _1, shaft tip portion 1 _two small ridges _{1 3,} by riding over the small protrusion _{2 11} Jikugakarigoana _{2 1,} proceeds towards the bottom of the hole of Jikugakarigoana _{2 1,} small ridges _{1 3} group and small protrusion 2 When ₁₁ and the group of dense deep engagement, strong sealing of the small protrusion 1 ₃ due to heat generation and shaft tip portion 1 ₂ and gripping member 2 of the main shaft 1 ₁ by thermal fusion between the small protrusion 2 ₁₁ It is something you can wear.

[0048]

According to a first aspect of the present invention according to the present invention, the bit body 1 ₄ and chuck gripping member 2, which together with the respective formed with predetermined dimensions and material of the steel, assembled bit since it is the ability to reduce material costs, it can be automated formation and their assembly with the waste less good yield further bit body 1 ₄ and gripping member 2 at the middle working materials, bits mass production It becomes possible to provide it to the market at low cost. Moreover, since the bit body 1 ₄ can be engaged wear select the one that corresponds to the type of the gripping member 2 of the chuck on the type of the chuck of the electric drill motor or air drilling machines, when orders for bit, bit body may be engaged to a predetermined gripping member 2 to 1 _4, thus it to use it effectively the bit body 1 ₄ and gripping member 2, it can be made significantly better adjustment of inventory. The fastening of the gripping member 2 to the bit body 1 _4, since by thermal fusion the shaft tip portion 1 ₂ to gripping member 2 is fastened, robust without this engagement is never disengaged This enables the engagement.

According to the second aspect of the invention, the bit body 1
The shaft tip portion _{1 2} of the spindle _{1 1 4,} the chuck gripping member 2
For engagement with the are tapered fit, and the fact is made firm, shaft tip portion 1 ₂ of the outer peripheral thin small protrusion 1 ₃ group and gripping member 2 of surface axial engagement is accurate and the group of the engagement hole 2 ₁ a hole wall surface of thin small protrusion 2 _11, the meshing dense heat generation due to friction, since the fastened by heat sealing,掴条body 2
May be further powerful ones fastening the main shaft 1 _1.

According to the invention of claim 3, the bit body 1
The axial front end portion 1 ₂ of ₄ of the main shaft 1 _1, since the grip member 2 of the chuck has a taper fitting, gripping member 2,
The spindle 1 ₁ can accurately且確Indeed fastening, Moreover, the outer peripheral surface of the shaft tip portion 1 ₂ of the spindle 1 ₁ and a shaft engaging hole 2 ₁ a hole wall surface of the gripping member 2, gritty without each land by the rough surface which is, when while rotating the main shaft 1 ₁ of the bit body 1 ₄ shaft tip portion 1 ₂ is pressed into the grip body 2 in the axial engagement holes 2 _1, frictional heat caused by contact with the contact surface the becomes hot, the shaft tip portion 1 ₂ can be thermally fused to the gripping member 2, further a strong ones fastening the main shaft 1 ₁ and gripping member 2 bit body 1 _4.

[Brief description of the drawings]

FIG. 1 is a front view of a drill bit according to an embodiment of the present invention,

FIG. 2 is a front view showing a conventional drill bit,

FIG. 3 is an exploded partial view of a chuck gripping portion of a drill bit according to an embodiment of the present invention,

FIG. 4 is a view showing a state in which the tip of the shaft of the bit is being pressed into the gripping body in the chuck gripping portion of the drill bit according to the embodiment of the present invention;

FIG. 5 is a broken cross-sectional view showing a state in which the tip end portion of the bit is press-fitted into the holding body and the two are engaged with each other in the chuck holding portion of the drill bit according to the embodiment of the present invention;

FIG. 6 is a diagram showing an enlarged cross section taken along line AA of FIG.

FIG. 7 is an exploded partial view of a chuck holding portion showing a second embodiment of the drill bit of the present invention.

[Explanation of symbols]

1 Rotating Work Tool 1 ₁ Spindle 1 ₂ Axis Tip Part 1 ₃ Small Ridge Line 1 ₄ Bit Body 1 ₅ Without Ground 2 Gripping Body 2 ₁ Axis Engagement Hole 2 ₁₁ Small Ridge Line 2 ₁₂ Without Ground

Claims (3)

(57) [Claims] The method according to claim 1] shaft tip portion 1 ₂ of the spindle 1 ₁ of the rotary tool 1 such as a drill bit or screwdriver bit, by press-fitting while rotating the shaft engaging hole 2 ₁ a gripping body 2 of the chuck shaft the gripping member 2 at the tip part 1 ₂ with forced fit fit, friction heat generated by friction between the shaft tip portion 1 ₂ and gripping member 2, the outer peripheral surface of the shaft tip portion 1 ₂ of the gripping member 2 axes engaging hole _{2 1}
The hole wall, the production method of the chuck gripping portion of the rotary tool, characterized in that is firmly fix the grip body 2 by heat sealing the shaft tip portion 1 ₂ of the spindle 1 _1. 2. A shaft tip portion 1 ₂ gripping member 2 of the main shaft 1 ₁ are engaged, at the tapered shaft, yet the shaft tip portion 1 ₂ is on the outer peripheral surface thereof, a thin small protrusion 1 ₃ groups of and an uneven by column installed at narrow intervals toward the longitudinal direction of the main axis 1 _1,
The rough rough ground surface is provided, also, gripping member 2 that tapered shaft tip portion 1 ₂ of the spindle 1 ₁ is engaged, together with the cross-section consists of profiles of polygonal cross-section, the shaft tip portion 1
₂ fits shaft coupling hole 2 ₁ is a tapered hole corresponding to the shaft tip portion 1 ₂ of the tapered small protrusion 2 ₁₁ narrow the hole wall, Jikugakarigoana 2 ₁ hole bottom in the hole wall of the shaft engaging hole 2 ₁ unevenness by column installed at narrow intervals in the direction of, rough, rotating working tool according to claim 1, characterized in that the rough ground surface Made in the chuck gripping part
Construction method . 3. A gripping member 2 and the main shaft 1 ₁ of the outer peripheral surface of the tapered shaft tip portion 1 ₂ engages the shaft tip portion 1 of the spindle 1 _1
2 is tapered shaft engaging hole 2 ₁ a hole wall surface of the gripping member 2 to be engaged, respectively, gritty, it coarse satin-like
The method for manufacturing a chuck gripping portion of a rotary work tool according to claim 1, wherein the grounds ₁₅ and 2 ₁₂ are used .