GB1568013A

GB1568013A - Wood auger

Info

Publication number: GB1568013A
Application number: GB8103/78A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1977-03-17
Filing date: 1978-03-01
Publication date: 1980-05-21
Also published as: FR2383763A1

Description

(54) WOOD AUGER (71) I, CHRISTO ALDRICH of South African nationality of 1 Doon Drive, Three Rivers, Vereeniging, Transvaal Province, Republic of South Africa do hereby declare the invention, for which I pray that a patent may be granted to me, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to a wood auger and to a method of making such auger. In particular the invention relates to a wood auger of the type having, at its free end, a pilot or feeding screw which pulls the auger into wood during drilling, thereby to render the auger self-feeding.

According to the invention there is provided a wood auger having a fluted body portion, at least one cutting lip and an axially arranged pilot screw for pulling the auger into the wood during drilling, the pilot screw being releasably attached to the body portion.

Further according to the invention there is provided a method of fabricating a wood auger having a fluted body portion and at least one cutting lip, which method includes the step of releasably attaching a prefabricated pilot screw to the free end of the body portion of the auger to project axially therefrom.

By 'free end" with reference to the auger is meant the end of the auger which leads during drilling and first penetrates and enters wood being drilled.

Preferably, the pilot screw may have a threaded portion and a shank, the shank being received and firmly located in an axially extending passage which opens out of the body portion's free end. The pilot screw may be retained in the passage by means of a pin insertable through a further passage in the body portion transverse to the pilot screw passage, the further passage registering with a recess in the shank of the pilot screw when the pilot screw is located in position in the pilot screw passage.

The invention also provides a body portion for use in the above described wood auger, wherein the body portion is fluted and has a cutting lip and has a hole at its leading end for removably receiving a shank of a pilot screw.

Further, the invention includes a pilot screw for use in the above described wood auger the screw comprising a threaded part and a shank formed with a transverse recess intermediate its ends.

The method may include the following steps prior to attaching the pilot screw to the body portion of the auger in any convenient sequence: providing an auger blank; fluting the blank on a milling machine to form a flute on the auger; drilling the passage co-axially into the free end of the fluted blank; and generating a cutting lip or lips at the free end of the blank by one or more milling operations.

The auger blank is preferably cut from bar stock.

The invention will now be described in detail. by way of example, with reference to the accompanying drawings, in which: Figure 1 shows an exploded part sectional side elevation of a wood auger according to the invention; and Figures 2(a) - (g) show diagrammatically the stages of fabrication of the auger of Figure 1.

In Figure 1 of the drawings, reference numeral 10 generally designates a wood auger in accordance with the invention. The auger comprises a fluted body portion 12 comprising cylindrical bar stock fabricated to have a flute 14 and cutting lips 16 and 17.

The auger further comprises a pilot screw or feeding screw. generally designated 18.

The free end 20 of the body portion 12 is provided with a bored passage 22 extending coaxially along the body portion and opening axially out of the free end 20.

The pilot screw 18 comprises a shank 24 at one end of and integral with a threaded bit portion 26. The shank 24 is received with a close fit in the passage 22, but for ease of illustration is shown out of the passage 22, in its position prior to insertion into the passage.

The body portion 12 is provided with a transverse, tangentially extending bored passage 28 intersecting the outer curved surface of the passage 22, the shank 24 having a corresponding semi-cylindrical recess 30. When the shank 24 is in its operative position in the passage 22, the recess 30 registers with the passage 28, to enable the pilot screw 18 to be held in position in the body portion 12 by means of a cotter pin (not shown). The cotter pin arrangement for locating the pilot screw in position in the body portion permits the pilot screw to be detached and replaced if necessary.

A method of making the wood auger 10 of Figure 1 will now be described with reference to Figures 2(a) - 2(g), in which the same reference numerals are used as in Figure 1. unless otherwise specified, and in Figures 2(c) - (e), the flute 14 is omitted for ease of illustration.

In Figure 2(a) reference numeral 32 generally designates an auger blank cut from bar stock. The blank 32 is then fluted on a milling machine, the fluted blank being shown by reference numeral 34 in Figure 2(b). The passage 22 is then drilled coaxially into the free end of the fluted blank, as shown in Figure 2(c).

After the passage 22 is drilled, the cutting lip 16 is generated by milling. as shown in Figure 2(d).

Finally, the passage 28 is drilled, and the pilot screw 18 (fabrication which is described hereunder with reference to Figures 2(f) and (g)) has its shank 24 inserted into the passage 22 so that the recess 30 registers with the passage 28, said passage 28 and recess 30 acting to receive a cotter pin (not shown) whereby the pilot screw 18 is attached and located in position in the passage 22.

The pilot screw 18 is produced in blank according to a mass production technique on an automatic lathe, the blank being shown by reference numeral 38 in Figure 2(f). The blank then has a screw thread generated on its bit portion 26 by grinding, as shown at 38 in Figure 2(g). The indentation 30 (not shown in Figures 2(f) and 2(g)) is formed at a convenient stage, so that the pilot screw 18 is entirely prefabricated before it is inserted in position as shown in Figure 2(e).

According to a method of forming wood augers previously known to the applicant, the pilot screw 18 was formed integrally with the body portion 12. According to that prior method, it was necessary, prior to fluting the bar stock, to rough machine the auger point on a lathe, to form a blank for the pilot screw. Furthermore, it was necessary to remove surplus metal from the auger point by milling with an end mill and a dividing head to generate a cutting lip. This cutting lip is shown by reference numeral 17 in Figure 1, and to remove the surplus metal formed a difficult operation. Thereafter further surplus metal was removed from the other side of the point by milling to generate the vertical cutting lip 16.Furthermore, after milling the flute with a ball nosed cutter, final cleaning up was necessary by way of filing around the pilot screw base, after which it was necessary to cut the pilot screw thread with a small specially made milling cutter adapted to operate clear of the vertical cutting lip 16. This was found to be an exceptionally difficult and expensive operation. Forming the flute and cleaning out the flute were performed, according to the prior method. in the same fashion as for the present invention.

The present invention thus has the substantial advantage that, due to the simplified and reduced number of method steps used in fabricating the wood auger, the wood auger can be produced at substantially reduced manufacturing cost, and the applicant believes tha it may be possible to reduce such manufacturing costs by up to about 25 per cent. By using metals of different characteristics for the body portion 12 and pilot screw 18. the method in accordance with the invention makes possible a wood auger having a pilot screw and a body portion of metals having different physical properties. This can be achieved, for example. by using. for the pilot screw 18, steel selected for its toughness after heat treatment, the steel being heat treated accordingly. For the auger body, a steel can be chosen which is capable of heat treatment to a high standard of hardness, so as to promote resistance to wear of the cutting lips. Finally, with the embodiment of the invention described with reference to Figure 1. it is possible for a user to replace broken or extremely worn pilot screws, while retaining the body portion 12 if it is still serviceable. Thus the necessity for discarding the whole wood auger, should the pilot screw for example become broken, is avoided.

WHAT I CLAIM IS: 1. A wood auger having a fluted body portion, at least one cutting lip and an axially arranged pilot screw for pulling the auger into wood during drilling, the pilot

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. provided with a bored passage 22 extending coaxially along the body portion and opening axially out of the free end 20. The pilot screw 18 comprises a shank 24 at one end of and integral with a threaded bit portion 26. The shank 24 is received with a close fit in the passage 22, but for ease of illustration is shown out of the passage 22, in its position prior to insertion into the passage. The body portion 12 is provided with a transverse, tangentially extending bored passage 28 intersecting the outer curved surface of the passage 22, the shank 24 having a corresponding semi-cylindrical recess 30. When the shank 24 is in its operative position in the passage 22, the recess 30 registers with the passage 28, to enable the pilot screw 18 to be held in position in the body portion 12 by means of a cotter pin (not shown). The cotter pin arrangement for locating the pilot screw in position in the body portion permits the pilot screw to be detached and replaced if necessary. A method of making the wood auger 10 of Figure 1 will now be described with reference to Figures 2(a) - 2(g), in which the same reference numerals are used as in Figure 1. unless otherwise specified, and in Figures 2(c) - (e), the flute 14 is omitted for ease of illustration. In Figure 2(a) reference numeral 32 generally designates an auger blank cut from bar stock. The blank 32 is then fluted on a milling machine, the fluted blank being shown by reference numeral 34 in Figure 2(b). The passage 22 is then drilled coaxially into the free end of the fluted blank, as shown in Figure 2(c). After the passage 22 is drilled, the cutting lip 16 is generated by milling. as shown in Figure 2(d). Finally, the passage 28 is drilled, and the pilot screw 18 (fabrication which is described hereunder with reference to Figures 2(f) and (g)) has its shank 24 inserted into the passage 22 so that the recess 30 registers with the passage 28, said passage 28 and recess 30 acting to receive a cotter pin (not shown) whereby the pilot screw 18 is attached and located in position in the passage 22. The pilot screw 18 is produced in blank according to a mass production technique on an automatic lathe, the blank being shown by reference numeral 38 in Figure 2(f). The blank then has a screw thread generated on its bit portion 26 by grinding, as shown at 38 in Figure 2(g). The indentation 30 (not shown in Figures 2(f) and 2(g)) is formed at a convenient stage, so that the pilot screw 18 is entirely prefabricated before it is inserted in position as shown in Figure 2(e). According to a method of forming wood augers previously known to the applicant, the pilot screw 18 was formed integrally with the body portion 12. According to that prior method, it was necessary, prior to fluting the bar stock, to rough machine the auger point on a lathe, to form a blank for the pilot screw. Furthermore, it was necessary to remove surplus metal from the auger point by milling with an end mill and a dividing head to generate a cutting lip. This cutting lip is shown by reference numeral 17 in Figure 1, and to remove the surplus metal formed a difficult operation. Thereafter further surplus metal was removed from the other side of the point by milling to generate the vertical cutting lip 16.Furthermore, after milling the flute with a ball nosed cutter, final cleaning up was necessary by way of filing around the pilot screw base, after which it was necessary to cut the pilot screw thread with a small specially made milling cutter adapted to operate clear of the vertical cutting lip 16. This was found to be an exceptionally difficult and expensive operation. Forming the flute and cleaning out the flute were performed, according to the prior method. in the same fashion as for the present invention. The present invention thus has the substantial advantage that, due to the simplified and reduced number of method steps used in fabricating the wood auger, the wood auger can be produced at substantially reduced manufacturing cost, and the applicant believes tha it may be possible to reduce such manufacturing costs by up to about 25 per cent. By using metals of different characteristics for the body portion 12 and pilot screw 18. the method in accordance with the invention makes possible a wood auger having a pilot screw and a body portion of metals having different physical properties. This can be achieved, for example. by using. for the pilot screw 18, steel selected for its toughness after heat treatment, the steel being heat treated accordingly.For the auger body, a steel can be chosen which is capable of heat treatment to a high standard of hardness, so as to promote resistance to wear of the cutting lips. Finally, with the embodiment of the invention described with reference to Figure 1. it is possible for a user to replace broken or extremely worn pilot screws, while retaining the body portion 12 if it is still serviceable. Thus the necessity for discarding the whole wood auger, should the pilot screw for example become broken, is avoided. WHAT I CLAIM IS:

1. A wood auger having a fluted body portion, at least one cutting lip and an axially arranged pilot screw for pulling the auger into wood during drilling, the pilot

screw being releasably attached to the body portion.

2. A wood auger as claimed in claim 1, wherein the pilot screw has a threaded portion and a shank, the shank being received and firmly located in an axially extending passage which opens out of the body portion's free end.

3. A wood auger as claimed in claim 2, wherein the pilot screw is retained in the passage by means of a cotter pin removably lnsertable in a further passage in the body portion transverse to the pilot screw passage, the further passage registering with a recess in the shank of the pilot screw when the pilot screw is located in position in the pilot screw passage.

4. A wood auger as claimed in claim 1, 2 or 3, wherein the pilot screw is of heat treated steel and the body portion of wear resistant steel which has been heat treated.

5. A body portion for use in the wood auger of any preceding claim, wherein the body portion is fluted and has a cutting lip and has a hole at its leading end for removably receiving a shank of a pilot screw.

6. A pilot screw for use in the wood auger of claim 3, the screw comprising a threaded part and a shank formed with a transverse recess intermediate its ends.

7. A method of fabricating a wood auger having a fluted body portion and at least one cutting lip, which method includes the step of releasably attaching a prefabricated pilot screw to the free end of the body portion of the auger to project axially therefrom.

8. A method as claimed in claim 7, wherein a pilot screw having a threaded bitportion and a shank has its shank located in an axially extending passage opening out of the free end of the body portion.

9. A method as claimed in claim X which includes the following steps prior to attaching the pilot screw to the body portion of the auger: providing an auger blank: fluting the blank on a milling machine to form a flute on the auger; drilling the passage co-axially into the free end of the fluted blank; generating a cutting lip or lips at the free end of the blank by milling; and cleaning out the flute at the free end of the blank by milling with a ball nosed cutter.

10. A wood auger substantially as described and as illustrated in the accompanying drawings.

11. A method of fabricating a wood auger substantially as described herein with reference to the accompanying drawings.

12. A wood auger whenever fabricated by the method as claimed in any one of claims 7 to 9.