JP2003236804A - Double-step drill for woodworking - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a double-step drill with which a double-step hole to form in a single operation a large diameter hole in an opening of a small diameter hole like a bolt hole having a seat where a bolt head or a nut is seated, and the large diameter hole with a smooth cutting surface is drilled. <P>SOLUTION: A small diameter drill 2 is protrudingly mounted to a rotation center of a large diameter drill 1. The small diameter hole is drilled with the small diameter drill, and the large diameter hole with the large diameter drill. The large diameter drill 1 is continuously formed of a bottom rake edge 4 and a side rake edge 3 in a plurality of positions on its outer circumference. An outer circumferential end of the bottom rake edge 4 and a lower end of the side rake edge 3 are made into a common edge point 5. The edge point 5 is made a forward end in a rotative direction, and the bottom rake edge 4 and the side rake edge 3 are formed backward in the rotative direction. A discharge groove 6 for discharging cutting chips is formed in front of these bottom rake edge and side rake edge. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention provides a two-step hole for forming a large-diameter hole at the opening end portion of a small-diameter hole, such as a bolt hole having a seat into which a bolt head or a nut is inserted. It is an invention relating to a two-stage structure that can be drilled by work.

[0002]

2. Description of the Related Art Conventionally, in order to drill a two-step hole such as a bolt hole with a seat, after a small-diameter bolt hole is drilled, a round bar-shaped guide is inserted into the bolt hole and a spot-drilling machine attached to the guide is used. A method of forming a seat by forming a large-diameter hole, and a method of attaching a small-diameter hole B protruding from the rotation center of the large-diameter hole A as shown in FIG. It is known that a large-diameter hole is drilled by using a pin.

The two-step cutting machine shown in FIG. 9 (a) is a large-diameter cutting machine A.
Both the small-diameter blade B and the small-diameter blade B are drills composed of a scribing blade C and a scooping blade D, and are mainly used for drilling a two-step hole having a relatively large diameter, and penetrate the center of the large-diameter blade. The protruding size of the small diameter is adjusted with the adjusting screw E.
In the two-step cutting tool shown in FIG. 9 (b), the tip is tapered, and a small diameter cutting tool B is attached to the center of a large diameter cutting tool having a cutting edge F formed on the inclined surface thereof. A large-diameter hole, that is, a large-diameter hole having a dish-like shape can be drilled.

[0004]

The conventional two-step drill, in which a round bar-shaped guide is inserted into a small-diameter hole and a large-diameter hole is bored by a countersunk hole attached to the guide, has a drawback that the boring work requires labor. , It is not possible to pierce the plate-shaped two-stage hole. Further, although the side surface of the large diameter hole can be smoothly drilled, there is a drawback that the bottom surface does not have a clean cutting surface. The two-step drill shown in FIG. 9 is capable of punching a plate-like two-step hole in a single operation, but has a drawback in that a large-diameter hole that has been drilled does not provide a clean cutting surface.
In view of the above-mentioned drawbacks of the prior art, the present invention provides a two-step drill capable of drilling a two-step hole in one operation and capable of drilling a large-diameter hole on a clean cutting surface. The purpose is.

[0005]

According to the present invention, a small-diameter wire 2 is attached so that a small-diameter wire 2 projects from the rotation center of a large-diameter wire 1.
In a two-step woodworking tool for drilling a large-diameter hole 8 in the opening of a small-diameter hole 7 drilled by, the large-diameter tool 1 has bottom rake blades 4 and side rake blades 4 continuously formed at a plurality of positions on the outer periphery, The outer peripheral edge of the bottom rake blade 4 and the lower edge of the side rake blade 3 serve as a common cutting edge 5. A bottom rake blade 4 and a side rake blade 3 are formed with the cutting edge 5 as the front end in the rotation direction toward the rear in the rotation direction, and a chip discharge groove 6 is formed in front of the bottom rake blade 4 and the side rake blade 3. .

With the above structure, the cutting edge 5 common to the bottom rake blade 4 and the side rake blade 3 sharply cuts the outer peripheral lower end of the large-diameter hole like a scribing blade, and the side surface and the bottom face are cut from the outer peripheral lower end. Cut each with a scooping blade. Therefore, the side surface and the bottom surface are cut into a smooth surface like a plank. At this time, the bottom rake blade 4 of the large diameter cutting tool 1
When the side rake blade 3 and the side rake blade 3 are formed in a shape that curves backward with the cutting tip 5 as the front end, the cutting is smoother. The bottom scooping blade 4 of the large-diameter cutting edge 1 can be formed with a large-diameter hole 8 having a plate-like shape when the center side is formed in an inclined direction in which it is inclined toward the front of the drill.
If the bottom rake blade 4 of the large-diameter drill 1 is formed in the horizontal direction orthogonal to the axis of the drill, the large-diameter hole 8 can be formed as a step hole at a right angle.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a two-step wood cutting tool according to the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a front view in which a large-diameter hole 1 and a small-diameter hole 2 are separated, and FIG. 2 is a front view showing a state in which the large-diameter hole 1 and the small-diameter hole 2 are set for use in perforation.

The large-diameter thread 1 is formed by integrally forming a cylindrical main body 1a having the same inner diameter as a large-diameter hole to be bored and a chuck shaft 1b projecting above the main body 1a. A mounting hole 9 having an inner diameter equal to the outer diameter of the small-diameter hole is formed in the center of the main body 1a. By inserting the upper end of the small-diameter hole 2 into the mounting hole 9 and screwing the two set bolts 10 and 10 arranged from the side surface of the large-diameter hole toward the center, the large-diameter hole 1 and the small-diameter hole 2 are attached. Fix it. Chamfers 11 and 11 are formed on the upper side surface of the small-diameter rim 2, and the chamfered part 11 is pressed by the set bolt 10 so that the large-diameter rim 1 and the small-diameter rim 2 are firmly fixed without deviating. To be done.

The small-diameter blade 2 to be mounted on the large-diameter blade 1 is a small blade.
Form a scribing blade 13 and a rake blade 14 at the tip of the 12
It is a general woodworking drill that protrudes a hole to form a through hole or a deep hole in a plate or a pillar. The small-diameter wire 2 is selected and mounted with an appropriate length depending on the purpose and use.

The basic shape of the lower end of the large-diameter end 1 is a substantially conical shape, and a mounting hole 9 is bored in the center thereof. Cutting blades for drilling are formed at two positions of the lower end of the large-diameter cutting edge formed in a substantially conical shape, facing each other. As shown in FIG. 2, the cutting blade for cutting is composed of a side rake blade 3 and a bottom rake blade 4, and the outer peripheral edge of the bottom rake blade 4 and the lower end of the side rake blade 3 serve as a common cutting edge 5 and a cutting edge 5 The side face rake blade 3 and the bottom face rake blade 4 are formed rearward with the front end in the rotation direction. In front of the side rake blade 3 and the bottom rake blade 4,
A discharge groove 6 is provided on the side surface of the main body portion 1a and is cut obliquely upward.

As shown in FIG. 2, the side face rake blade 3 is formed in a curved shape in which the cutting tip 5 is the front end and retracts backward. At this time, as a result of forming the discharge groove 6 from the cutting edge of the side surface rake blade 3 so as to scoop the rake face, as shown in FIG. 3, a sharp rake blade having a relatively large rake angle α is formed. In this way, the blade line of the side rake blade 3 is moved backward and the sharp rake blade is formed. As a result, the side surface of the large-diameter hole drilled realizes a smooth cutting surface like a cutting surface by a planer. be able to.

On the other hand, the bottom face rake blade 4 formed on the lower end inclined surface of the main body portion 1a is formed in a curved shape in which its blade line recedes rearward in the rotational direction as shown in FIG.
A sharp edge is formed by taking a clearance angle β in addition to a relatively small rake angle α. By taking the clearance angle β, the lower end surface of the main body portion 1a is not a strict conical surface, but a deformed substantially conical shape in which the portion behind the bottom rake blade 4 is displaced upward. As described above, by retreating the blade line of the bottom face rake blade 4 having an acute angle to the rear and taking an appropriate clearance angle, the bottom face of the large-diameter hole drilled is like a cutting face by a planer like the side face. Can achieve a smooth cutting surface

FIG. 6 shows a perforation process by the two-step cutting shown in FIGS. 1 to 5. That is, as shown in FIG. 6 (a), a plate or the like is perforated with a small-diameter hole 2, and after the protruding portion of the small-diameter hole 2 enters the surface of the plate, it is further advanced to make a perforation with a large-diameter hole 1, The drilling work is completed when the large-diameter hole 1 reaches the planned depth. In this way, as shown in FIG. 6 (b), a two-stage hole in which a large-diameter hole 8 having a dish-like shape is formed at the open end portion of the small-diameter hole 7 can be perforated in one operation. . This two-stage hole is often used mainly when mounting countersunk bolts.

FIG. 7 is a lower perspective view of a large-diameter barbed double-deck for woodworking showing another embodiment. The bottom face rake blade 4 formed on the bottom face of the large-diameter edge 1 is formed in a direction orthogonal to the axis, that is, in the horizontal direction. The small-diameter wire 2 described above is attached to the large-diameter wire 1 of this embodiment, and a punching operation is performed as shown in FIG. In this way, in the two-step cutting in which the bottom rake blade 4 is formed in the direction orthogonal to the axial center of the large diameter cutting edge 1, that is, in the horizontal direction, as shown in FIG. It is possible to drill a two-step hole in which the large diameter hole 8 is formed as a step at a right angle to the end portion. The two-stage hole is widely used, for example, when a bolt head or a nut of an ordinary hexagon bolt is used without protruding.

[0015]

According to the two-step drill for woodworking of the present invention as set forth in claim 1, the cutting edge located at the front end in the rotational direction is sharply cut like a scoring blade, and a large-diameter hole is formed by the side rake blade following the cutting edge. The side surface is cut like a planer by the bottom scooping blade like a plank, and the chips are smoothly removed from the discharge groove, and the entire inner surface of the large diameter hole, that is, the side surface and the bottom surface are removed once. There is an effect that a smooth surface can be finished by piercing work.

According to the second aspect of the present invention, the bottom rake blade and the side rake blade for cutting the bottom surface and the side surface of the large diameter hole cut the respective cutting surfaces more smoothly, and the entire inner surface of the large diameter hole is cut. There is an effect that a smoother surface can be finished.

According to the third aspect of the present invention, it is possible to form the plate-like two-stage hole by a single operation, and the cutting surfaces of the side surface and the bottom surface can be finished to be smooth surfaces. is there.

According to the invention of claim 4, it is a large-diameter small-diameter two-step hole in which a horizontal step is formed, that is, a right-angled step hole, and the side and bottom cutting surfaces are finished to be smooth surfaces. There is an effect that can be.

[Brief description of drawings]

FIG. 1 is a front view of a two-step woodwork of the present invention, in which a large-diameter cutout and a small-diameter cutout are separated.

FIG. 2 is a front view showing a state in which a large-diameter cutting edge and a small-diameter cutting edge are set;

FIG. 3 is a sectional view taken along line III-III of FIG.

FIG. 4 is a bottom view of only the large-diameter cutout,

5 is a sectional view taken along line VV of FIG.

FIG. 6 is a vertical cross-sectional view showing a perforated state by the two-step woodworking machine of the present invention,

FIG. 7 is a lower perspective view of only the large-diameter rim showing another embodiment,

FIG. 8 is a vertical cross-sectional view showing a state of perforation by the two-step woodworking tool of the embodiment shown in FIG.

FIG. 9 is a front view showing an example of a conventional two-step wood cutting tool.

[Explanation of symbols]

1 ... Large diameter, 1a ... Main body, 1b ... Chuck shaft, 2
… Small diameter cutout, 3… Side rake blade, 4… Bottom rake blade, 5… Cut point, 6… Discharge groove, 7… Small diameter hole, 8…
Large-diameter holes, 9 ... Mounting holes, 10 ... Set bolts, 11 ... Chamfered parts, 12 ... Small blades, 13 ... Scribe blades, 14 ... Scraping blades, 15 ... Screws, 16 ... Plates.

Claims (4)

[Claims] 1. A two-step woodworking tool for woodworking, in which a small-diameter hole is protruded from the center of rotation of a large-diameter hole and mounted, and a large-diameter hole is formed as a step hole at the opening of the small-diameter hole.
Large-diameter rims have bottom rake blades and side rake blades continuously formed at multiple positions on the outer circumference, and the outer edge of the bottom rake blade and the lower edge of the side rake blade serve as the common cutting edge, and the cutting edge is the front end in the direction of rotation. A double-sided wood cutting tool characterized in that bottom rake blades and side rake blades are formed toward the rear in the direction, and chip discharge grooves are formed in front of these bottom rake blades and side rake blades. 2. A double-ended woodworking tool for woodworking according to claim 1, wherein the bottom rake blade and the side rake blade of the large-diameter cutting tool are formed in a shape curving rearward with the cutting edges as front ends. 3. A two-step woodworking tool for woodworking according to claim 1 or 2, wherein the bottom rake blade of the large diameter cutting tool is formed in a tilting direction in which the center side is tilted toward the front of the cutting tool. 4. A two-step woodworking tool for woodworking according to claim 1 or 2, wherein the bottom rake blade of the large diameter cutting tool is formed in a horizontal direction orthogonal to the axis of the cutting tool.