TWI838791B - Drill screw structure and manufacturing method thereof - Google Patents

Abstract

The present invention provides a drill-end screw structure and a manufacturing method thereof. The manufacturing method comprises: providing a screw body, forming a drill-end screw segment, forming a concave neck, forming a drill-end cutting edge and forming a thread. The drill-end screw structure comprises a screw head and a screw portion. The screw portion is provided with a threaded screw segment, a drill-end screw segment and a drill head screw segment in sequence. The threaded screw segment has a threaded rod diameter and the thread. The drill-end screw segment has a drill-end rod diameter, a composite thread, and a thread. The invention discloses a drill tail screw structure having a plurality of drill tail cutting edges and a plurality of drill tail chip removal grooves arranged in a staggered manner. The drill head screw segment is provided with a concave neck with an arc surface, a positioning portion and a tip portion in sequence from the end connected to the drill tail screw segment. The drill head screw segment is convexly provided with a plurality of drill head cutting edges and the drill head chip removal grooves arranged in a staggered manner. One end of the concave neck is connected to the drill tail cutting edges, and the other end is connected to the drill head cutting edges, so as to reduce the left and right shaking problem of the drill tail screw structure and increase the stability when drilling.

Description

Drill screw structure and manufacturing method thereof

The present invention relates to a drill screw, in particular to a drill screw structure having a curved surface design and a non-connected cutting edge and a chip removal groove capable of rapid chip removal, and a manufacturing method thereof.

The known drill screws are generally directly stamped with the relative chip grooves and cutting edges. Since these chip grooves are stamped on a plane by a stamping die, the chip grooves can only be designed to extend vertically or slightly inclined on the plane. However, this known drill screw has the advantage of mass production.

However, although the known direct stamping drill screw has the advantage of mass production, after the front end is fixed and drilled, the drill screw formed by the known stamping method has poor chip removal ability. Therefore, it is easy to shift during the drilling process, causing the drilling position to deviate from the predetermined position. In view of this, the inventor has conducted intensive research and combined what he has learned to address the above problem and proposed a drill screw structure that produces two different discontinuous cutting edges in the stamping method and the thread rolling method to overcome the known shortcomings.

The purpose of the present invention is to form different cutting edges by punching and thread rolling, and connect the cutting edges formed by different methods by a concave neck, so as to solve the problem that the drill screw used in the above-mentioned prior art cannot effectively remove chips and has poor stability when expanding the hole.

To achieve the above-mentioned purpose, the present invention provides a method for manufacturing a drill screw, which is used to manufacture a drill screw with a thread of the same thread outer diameter formed on different rod diameters. The method comprises: providing a screw body, the screw body having a screw head and a screw rod extending from one side of the screw head along the axial direction of the screw head; forming a drill screw rod section, and sequentially forming a threaded screw from the screw head to the screw rod. The invention relates to a screw segment, a drill tail screw segment, and a drill head screw segment, wherein the threaded screw segment has a threaded rod diameter, and the drill tail screw segment has a drill tail rod diameter; a concave neck is formed, and a concave neck, a positioning portion and a tip portion are formed by stamping from the drill head screw segment, and the drill head screw segment is axially adjacent to the end of the drill tail screw segment and is sequentially composed of the concave neck, the positioning portion and the end portion, wherein the tip portion is formed by gradually contracting from the end adjacent to the positioning portion toward the other end thereof. A static point, and the concave neck is concavely arranged from the adjacent end of the drill tail screw segment along the axial direction toward the positioning portion to form an arc surface, and the drill head screw segment forms a plurality of drill head cutting edges and a plurality of drill head chip removal grooves from the static point along the axial direction toward the concave neck, and the drill head chip removal grooves are each located between the adjacent drill head cutting edges; a drill tail cutting edge is formed, and a plurality of drill tail cutting edges and a plurality of drill tail chip removal grooves are formed by rolling the threads from the end of the drill tail screw segment connected to the concave neck, and the drill tail chip removal grooves are Each of the adjacent drill tail cutting edges has a drill tail cutting edge outer diameter; and a thread is formed, from the threaded screw section connected to the drill tail screw section end to form a thread by rolling, wherein the thread extends axially to the screw head portion, and the thread has a thread outer diameter; wherein the drill tail rod diameter is smaller than the threaded rod diameter and greater than zero, and one end of the concave neck is connected to the drill tail cutting edges, and the other end is connected to the drill head cutting edges.

Furthermore, the concave neck portion gradually expands axially toward the drill screw segment and the positioning portion, and the end of the threaded screw segment adjacent to the drill screw segment gradually contracts toward the drill screw segment.

Furthermore, each of the drill tail cutting edges has a first helical surface, a second helical surface and a drill tail helical angle, wherein the drill tail helical angle is formed at the junction of each of the first helical surface and each of the second helical surface.

Furthermore, the drill tail cutting edges are asymmetrical structures, and the first distance from the drill tail helix angle to the drill tail screw segment surface of each of the first helical surfaces of the drill tail cutting edges is smaller than the second distance from the drill tail helix angle to the drill tail screw segment surface of each of the second helical surfaces and is greater than zero.

Furthermore, the outer diameter of the drill tail cutting edge is smaller than or equal to the outer diameter of the thread.

Furthermore, the drill screw structure manufactured by the manufacturing method of the drill screw mainly includes a screw head and a screw rod portion extending outward from the screw head, and the screw rod portion is formed in sequence along the axial direction from the screw head portion to form a threaded screw section, a drill screw section, and a drill screw section, and the threaded screw section has a The threaded rod diameter and a thread protruding on the threaded screw segment, the drill tail screw segment has a drill tail rod diameter, a plurality of drill tail cutting edges protruding on the drill tail screw segment and a plurality of drill tail chip removal grooves located between the adjacent drill tail cutting edges, the drill tail cutting edges each having a drill tail cutting edge outer diameter, and the drill head screw segment is connected to the The end of the drill screw segment is provided with a concave neck, a positioning portion and a tip portion in sequence along its axial direction. The tip portion is gradually contracted along the axial direction from the end adjacent to the positioning portion toward the other end thereof to form a static point, and the concave neck is concavely arranged along the axial direction from the end adjacent to the drill screw segment toward the positioning portion to form an arc surface, and the drill screw segment is gradually contracted along the axial direction from the static point to the tip portion. The point is convexly arranged along the axial direction toward the concave neck to form a plurality of drill cutting edges and a plurality of drill chip grooves, and the drill chip grooves are each located between the adjacent drill cutting edges, wherein the drill tail rod diameter is smaller than the thread rod diameter and greater than zero, and one end of the concave neck is connected to the drill tail cutting edges, and the other end is connected to the drill cutting edges.

Furthermore, the concave neck of the drill screw section gradually expands axially toward the drill tail screw section and the positioning portion, and the drill chip grooves extend from the static point through the tip portion, the positioning portion to a portion of the concave neck.

The screw body first performs the step of forming a drill tail screw section, so that the drill tail rod diameter of the drill tail screw section is smaller than the thread rod diameter of the threaded screw section, and then performs the step of forming a concave neck.

The screw body simultaneously implements the step of forming the drill-end screw section and the step of forming a concave neck.

Therefore, the present invention has the following beneficial effects compared to the prior art:

1. The manufacturing method of the drill screw of the present invention mainly forms the concave neck, the positioning part, the tip, the drill cutting edges and the drill chip grooves on the drill screw section by stamping, and then forms the drill tail cutting edges and the drill tail chip grooves by rolling, and the concave neck is respectively connected to the drill cutting edges at one end and the drill tail cutting edges at the other end, thereby forming a cutting edge structure with different manufacturing processes to increase the manufacturing yield.

2. The drill tail screw structure manufactured by the manufacturing method of the drill tail screw of the present invention mainly has the concave neck between the drill head cutting edge and the drill tail cutting edge, so that when the chips generated by the drill head cutting edge are discharged through the drill head chip discharge groove, the chips are randomly sent to the drill tail chip discharge groove of the drill tail screw section when passing through the concave neck. In this way, the chips will not accumulate due to the drill tail chip discharge groove and cause the problem of left and right shaking, thereby increasing the stability of the drill tail screw structure when drilling holes.

10: Screw body

11:Screw head

12: Screw part

121: Threaded screw section

1211: Thread

122: Drill tail screw segment

1221: Drill tail cutting edge

1222: Drill tail chip groove

1223: First spiral surface

1224: Second spiral surface

123: Drill screw segment

1231: Concave neck

1232: Positioning Department

1233: Tip

1234: Drill cutting edge

1235: Drill bit chip groove

P:Stay still

Z: Axial direction

D1: threaded rod diameter

D2: Drill tail rod diameter

R1: outer diameter of the cutting edge at the end of the drill

R2: thread outer diameter

α: Drill tail helix angle

d1: first distance

d2: second distance

Figure 1: A schematic diagram of the manufacturing process of the drill screw of the present invention.

Figure 2-1 to Figure 2-3: Schematic diagrams of the manufacturing process and corresponding molding structure of the drill bit screw of the present invention.

Figure 3: A side view of the drill-screw structure of the present invention.

Figure 4: An enlarged diagram of circle A in Figure 3.

Figure 5: An enlarged schematic diagram of circle B in Figure 3.

Figure 6: A three-dimensional schematic diagram of the drill-end screw structure of the present invention.

Figure 7: A three-dimensional schematic diagram of the drill-screw structure of the present invention from another perspective.

Figure 8: A schematic cross-sectional view of the drill-end screw structure of the present invention.

Figure 9: An enlarged schematic diagram of the cross section circled at C in Figure 8.

Figure 10: A schematic diagram of another manufacturing method of the drill screw of the present invention.

Several preferred implementation modes of the technical features and operation methods of this application are listed below, and are briefly described with illustrations for your reference. Furthermore, the proportions of the drawings in this invention may not be drawn according to the actual proportions for the convenience of explanation, and the proportions in the drawings shall not be used to limit the scope of protection sought by this invention.

Regarding the content of the present invention, please refer to Figures 1 to 10, which are embodiments of the present invention. The present invention provides a method for manufacturing a self-drilling screw, which is used to manufacture a self-drilling screw with threads of the same thread outer diameter formed in different rod diameter widths. Please refer to Figures 2-1 to 3. The method for manufacturing the self-drilling screw includes: providing a screw body, providing a screw body 10 having a screw head portion 11 and a screw rod portion 12 extending from one side of the screw head portion 11 along the axial direction Z of the screw head portion 11.

A drill screw segment is formed, and the screw portion 12 is sequentially formed into a threaded screw segment 121, a drill screw segment 122, and a drill head screw segment 123 from the connection of the screw head portion 11, wherein the threaded screw segment 121 has a thread diameter D1, and the drill screw segment 122 has a drill head diameter D2, wherein the drill screw segment 122 and the drill head screw segment 123 of this embodiment are formed by stamping.

A concave neck is formed. Please refer to FIG. 3 again. A concave neck 1231, a positioning portion 1232 and a tip portion 1233 are formed by stamping from the drill screw segment 123. The drill screw segment 123 is formed with the concave neck 1231, the positioning portion 1232 and the tip portion 1233 in sequence along the axial direction Z from the end adjacent to the drill screw segment 122. The tip portion 1233 is formed by gradually contracting along the axial direction Z toward the other end of the positioning portion 1232 from the end adjacent to the drill screw segment 122 to form a static point P, and the concave neck 1231 is gradually expanded along the axial direction Z toward the drill screw segment 122 and the positioning portion 1232, and is formed by gradually contracting along the axial direction Z toward the other end of the drill screw segment 122 and the positioning portion 1232, and is formed by gradually contracting along the axial direction Z toward ... The end of the drill tail screw segment 122 is concave toward the positioning portion 1232 along the axial direction Z to form an arc surface, and the threaded screw segment 121 adjacent to the end of the drill tail screw segment 122 is gradually reduced toward the direction of the drill tail screw segment 122. The drill head screw segment 123 is formed from the static point P along the axial direction Z toward the concave neck 1231 to form a plurality of drill heads. The cutting edge 1234 and the plurality of drill chip grooves 1235 are each located between the adjacent drill cutting edges 1234. In addition, the drill chip grooves 1235 extend from the static point P through the tip 1233 and the positioning portion 1232 to a portion of the concave neck 1231.

A drill tail cutting edge is formed, and a plurality of drill tail cutting edges 1221 and a plurality of drill tail chip removal grooves 1222 are formed by rolling the threads from the end of the drill tail screw section 122 connected to the concave neck 1231. The drill tail chip removal grooves 1222 are each located between the adjacent drill tail cutting edges 1221, and the drill tail cutting edges 1221 each have a drill tail cutting edge outer diameter R1, and the drill tail cutting edges 1221 each have a first helical surface 1223, a second helical surface 1224 and a drill tail helical angle α, wherein In the embodiment, the joint of each first helical surface 1223 and each second helical surface 1224 forms a drill tail helix angle α, and the drill tail cutting edges 1221 are asymmetric structures, and the first distance d1 from the drill tail helix angle α to the surface of the drill tail screw segment 122 of each first helical surface 1223 of the drill tail cutting edges 1221 is smaller than the second distance d2 from the drill tail helix angle α to the surface of the drill tail screw segment 122 of each second helical surface 1224 and is greater than zero.

A thread is formed, and a thread 1211 is formed by rolling the thread from the threaded screw section 121 to the end of the drill tail screw section 122, wherein the thread 1211 extends along the axial Z spiral to the screw head 11, and the thread 1211 has a thread outer diameter R2, and the outer diameter R1 of the drill tail cutting edge is smaller than or equal to the thread outer diameter R2.

In particular, please refer to FIG. 1, the screw body 10 can simultaneously implement the step of forming the drilled screw segment and the step of forming a concave neck, or, please refer to FIG. 10, the screw body first performs the step of forming the drilled screw segment, so that the drilled rod diameter D2 of the drilled screw segment 122 is smaller than the threaded rod diameter D1 of the threaded screw segment 121, and then The step of forming a concave neck is performed. The screw body 10 of this embodiment simultaneously performs the step of forming a drill screw segment and the step of forming a concave neck, so that the screw body 10 forms the drill screw segment 122 at the same time when the drill screw segment 123 is stamped to form the concave neck 1231, the positioning portion 1232 and the tip portion 1233.

Furthermore, the drill screw structure manufactured by the manufacturing method of the drill screw mainly includes the screw head portion 11 and the screw rod portion 12 extending outward from the screw head portion 11, and the screw rod portion 12 is formed from the screw head portion 11 along the axial direction Z in sequence to form the threaded screw segment 121, the drill screw segment 122, and the drill screw segment 123, and the threaded screw segment 121 has the threaded rod The thread 1211 protrudes from the threaded screw section 121, the drill tail screw section 122 has the drill tail diameter D2, the drill tail cutting edges 1221 protrudes from the drill tail screw section 122, and the drill tail chip grooves 1222 located between the adjacent drill tail cutting edges 1221, the drill tail cutting edges 1221 each have the drill tail cutting edge outer diameter R1, and the drill head screw section 123 is self-tipped. The concave neck 1231, the positioning portion 1232 and the tip 1233 are sequentially arranged along the axial direction Z of the drill tail screw section 122. The tip 1233 is formed by gradually contracting from the end adjacent to the positioning portion 1232 along the axial direction Z toward the other end thereof to form the static point P. The concave neck 1231 is formed by concavely arranged from the end adjacent to the drill tail screw section 122 along the axial direction Z toward the positioning portion 1232 to form the arc surface. The head screw section 123 is convexly provided from the static point P along the axial direction Z toward the concave neck 1231 to form the drill cutting edges 1234 and the drill chip grooves 1235. The drill chip grooves 1235 are located between the adjacent drill cutting edges 1234. Please refer to FIG. 3 again, and the drill chip grooves 1235 do not extend to the minimum diameter of the concave neck 1231. The diameter of the drill tail rod D2 The diameter D2 of the threaded rod 122 is smaller than the diameter D1 of the threaded rod and is greater than zero, and one end of the concave neck 1231 is connected to the drill tail cutting edges 1221, and the other end is connected to the drill head cutting edges 1234. In this embodiment, when forming a drill tail screw segment, the drill tail rod diameter D2 of the drill tail screw segment 122 is first made smaller than the diameter D1 of the threaded rod 121, but it is not limited to this. The drill tail screw structure is formed in the step of forming a During the step of forming the concave neck, the diameter D2 of the drill bit screw segment 122 can be made smaller than the diameter D1 of the threaded screw segment 121. Moreover, the length of the drill bit screw segment 122 will affect the thickness of the workpiece that the drill bit screw can drill. Therefore, the drill bit screw segment 122 should be greater than or equal to the thickness of the workpiece. The drill head screw segment 123 is used to position the drill bit screw for drilling the workpiece. The ratio of the total length of the positioning portion 1232 and the tip portion 1233 to the length of the concave neck portion 1231 is less than or equal to 0.86 and greater than or equal to 0.62. In the present embodiment, when the drill tail cutting edge outer diameter R1 is used as the M8 screw specification, the ratio of the total length of the positioning portion 1232 and the tip portion 1233 to the length of the concave neck portion 1231 is 0.75. When the diameter R1 is a 1/4 inch screw specification, the ratio of the total length of the positioning portion 1232 and the tip portion 1233 to the length of the concave neck 1231 is 0.625, and when the outer diameter R1 of the drill tail cutting edge is a 7/32 inch screw specification, the ratio of the total length of the positioning portion 1232 and the tip portion 1233 to the length of the concave neck 1231 is 0.714, but not limited thereto.

In addition, referring to FIGS. 2 to 5, the screw body 10 is configured such that the outer diameter R1 of the drill tail cutting edge 1221 is substantially the same as the outer diameter R2 of the thread 1211, so that the drill tail rod diameter D2 of the drill tail screw segment 122 is smaller than the thread rod diameter D1 of the threaded screw segment 121. Thus, in the step of forming a drill tail cutting edge, the drill tail cutting edges on the drill tail screw segment 122 are The outer diameter R1 of the drill tail cutting edge 1221 is substantially the same as the outer diameter R2 of the thread 1211, so that the drill tail screw structure is easy to drill into the workpiece and external chips. In addition, the drill head cutting edges 1234 and the drill tail cutting edges 1221 are respectively formed on the drill head screw section 123 and the drill tail screw section 122, and the concave necks 1234 and the drill tail cutting edges 1221 are respectively provided between the drill head cutting edges 1234 and the drill tail cutting edges 1221. 31. Thus, when drilling a workpiece, the chips discharged from the drill head chip groove 1235 will be discharged from the drill head chip groove 1235 through the concave necks 1231 and then from at least one of the drill tail chip grooves 1222 of the drill tail screw segment 122. Thus, not only can the pressure of the chips on the drill head chip grooves 1235 and the drill tail chip grooves 1222 be reduced, but also the chips can be discharged through the drill head chip grooves 1235 and the drill tail chip grooves 1222. The drill tail cutting edges 1221 perform a second cutting of the chips from the drill head chip grooves 1235, so that the chips can be removed smoothly. In addition, the first helical surfaces 1223 of the drill tail cutting edges 1221 and the peripheral surface of the drill tail screw segment 122 have different first distances d1. Therefore, the drill tail chip grooves 1222 and the drill tail cutting edges 1221 are designed asymmetrically to increase their service life.

In summary, the manufacturing method of the drill screw of the present invention mainly forms the drill screw segment 123 having the concave neck 1231, the positioning portion 1232, the tip portion 1233, the drill cutting edges 1234 and the drill chip removal grooves 1235 by stamping, and then forms the drill tail cutting edges 1221 and the drill tail chip removal grooves 1222 by thread rolling, and the concave neck 1231 is respectively connected to the drill cutting edges 1234 at one end and the drill tail cutting edges 1221 at the other end, thereby forming the structures of the drill cutting edges 1234 and the drill tail cutting edges 1221 with different manufacturing processes, thereby increasing the cost of the drill screw segment 1233. The manufacturing yield of the drill tail screw manufactured by the manufacturing method is mainly that the drill head cutting edge 1234 and the drill tail cutting edge 1221 have the concave neck 1231, whereby the chips generated by the drill head cutting edge 1234 are discharged through the drill head chip discharge groove 1235. When passing through the concave neck 1231, the chips can be randomly sent to the drill tail chip grooves 1222 of the drill tail screw section 122. In this way, the chips will not accumulate due to the drill tail chip grooves 1222, thereby reducing the left and right shaking problem of the drill tail screw structure and increasing the stability of the drill tail screw structure when drilling.

11:Screw head

12: Screw part

121: Threaded screw section

1211: Thread

122: Drill tail screw segment

1221: Drill tail cutting edge

1222: Drill tail chip groove

1223: First spiral surface

1224: Second spiral surface

123: Drill screw segment

1231: Concave neck

1232: Positioning Department

1233: Tip

1234: Drill cutting edge

1235: Drill bit chip groove

P:Stay still

Z: Axial direction

R1: outer diameter of the cutting edge at the end of the drill

R2: thread outer diameter

Claims (10)

A method for manufacturing a drill screw is used to manufacture a drill screw with a thread having the same thread outer diameter formed on different rod diameters. The method comprises: providing a screw body, providing a screw body having a screw head and a screw rod extending from one side of the screw head along the axial direction of the screw head; forming a drill screw rod section, and sequentially forming a threaded screw rod section, a drill screw rod section, a drill screw rod section, and a drill screw rod section from the screw head joint. The threaded screw segment has a threaded rod diameter, and the drill tail screw segment has a drill tail rod diameter; a concave neck is formed, and a concave neck, a positioning portion and a tip portion are formed by stamping from the drill head screw segment, and the drill head screw segment includes the concave neck, the positioning portion and the tip portion in sequence along the axial direction from the end adjacent to the drill tail screw segment, wherein the tip portion is gradually contracted toward the other end along the axial direction from the end adjacent to the positioning portion to form a static point, and the concave neck is formed from the end adjacent to the drill The end of the tail screw segment is axially concave toward the positioning portion to form an arc surface, and the drill screw segment forms a plurality of drill cutting edges and a plurality of drill chip removal grooves from the static point along the axial direction toward the concave neck, and the plurality of drill chip removal grooves are located between the adjacent drill cutting edges; a drill tail cutting edge is formed, and a plurality of drill tail cutting edges and a plurality of drill tail chip removal grooves are formed by rolling the threads from the end of the drill tail screw segment connected to the concave neck, and the plurality of drill tail chip removal grooves are located between the adjacent drill tail cutting edges, and the drill tail cutting edges are Each has an outer diameter of a drill tail cutting edge; and a thread is formed, from the threaded screw section to the end of the drill tail screw section by rolling the threads to form a thread, wherein the thread is extended axially to the screw head, and the thread has an outer diameter of the thread; wherein the drill tail rod diameter is smaller than the threaded rod diameter and greater than zero; wherein one end of the concave neck is connected to the drill tail cutting edges, and the other end is connected to the drill head cutting edges, and the drill head chip grooves do not extend to the minimum diameter width of the concave neck. In the manufacturing method of the drill screw as described in claim 1, further, the concave neck portion is axially expanded toward the drill screw segment and the positioning portion, respectively, and the end of the threaded screw segment adjacent to the drill screw segment is gradually contracted toward the drill screw segment. The manufacturing method of the drill screw as described in claim 1, further, each of the drill cutting edges has a first helical surface, a second helical surface and a drill helical angle, wherein the drill helical angle is formed at the joint between each of the first helical surface and each of the second helical surface. As for the manufacturing method of the drill screw as described in claim 1, further, the screw body first performs the step of forming the drill screw section, so that the drill rod diameter of the drill screw section is smaller than the thread rod diameter of the threaded screw section, and then performs the step of forming a concave neck. The manufacturing method of the drill bit screw as described in claim 1, further, the screw body simultaneously implements the step of forming the drill bit screw rod section and the step of forming a concave neck. A drill-end screw structure mainly comprises: a screw head; a screw rod portion extending outward from the screw head portion, the screw rod portion sequentially forms a threaded screw rod section, a drill-end screw rod section, and a drill-end screw rod section axially from the screw head portion joint, and the threaded screw rod section has a thread rod diameter and a protrusion disposed on the threaded screw rod section. The drill screw segment has a drill tail diameter, a plurality of drill tail cutting edges protruding from the drill tail screw segment, and a plurality of drill tail chip removal grooves located between the adjacent drill tail cutting edges, each of the drill tail cutting edges has a drill tail cutting edge outer diameter, and the drill head screw segment is provided with a concave neck in sequence along its axial direction from the end connected to the drill tail screw segment. The tip portion is formed by gradually contracting from the end adjacent to the positioning portion along the axial direction toward the other end thereof to form a static point, and the concave neck portion is formed by concavely setting from the end adjacent to the drill tail screw segment along the axial direction toward the positioning portion to form an arc surface, and the drill head screw segment is formed by convexly setting from the static point along the axial direction toward the concave neck portion to form a plurality of drill head cutting edges and a plurality of A number of drill chip grooves, wherein the drill chip grooves are located between adjacent drill cutting edges; wherein the drill tail rod diameter is smaller than the thread rod diameter and greater than zero; wherein one end of the concave neck is connected to the drill tail cutting edges, and the other end is connected to the drill cutting edges, and the drill chip grooves do not extend to the minimum diameter width of the concave neck. The drill bit screw structure as described in claim 6, wherein the concave neck of the drill bit screw section is gradually expanded axially toward the drill bit screw section and the positioning portion, respectively, and the drill bit chip grooves extend from the static point through the tip portion, the positioning portion to a portion of the concave neck. The drill screw structure as described in claim 6, wherein each of the drill cutting edges has a first helical surface, a second helical surface and a drill helical angle, and the drill helical angle is formed at the junction of each of the first helical surface and each of the second helical surface. As for the drill screw structure described in claim 8, further, the drill cutting edges are asymmetrical structures, and the first distance from the drill helix angle to the drill screw segment surface of each of the first helical surfaces of the drill cutting edges is smaller than the second distance from the drill helix angle to the drill screw segment surface of each of the second helical surfaces and is greater than zero. A drill tail screw structure as described in claim 6, wherein the outer diameter of the drill tail cutting edges is less than or equal to the outer diameter of the thread.

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