GB2117286A - Drill tool - Google Patents

Abstract

The tool comprises a drill chuck co-operating shaft (11), a hollow cutting bit (1) and a spring loaded centre guide (3) adapted to be removably located in the centre bore (12) of the cutting bit (1). It may further incorporate a vertical slot (14) to allow venting of drilled-out material from the inside of the hollow section (12) and a depth guide (4) may also be fitted to the hollow section (12). The tool is used for removing broken screws nails etc from wooden or other surfaces. <IMAGE>

Description

SPECIFICATION Wood working tool The present invention relates to a woodworking tool or the like and is more particularly concerned with a tool for removing broken screws, embedded panel pins and the like from wooden or similar surfaces.

According to the invention there is provided a wood-working tool or the like for use with a drill comprising (i) a drill chuck co-operating shaft, (ii) a hollow cutting bit and (iii) a spring loaded centre guide adapted to be removably located in the centre bore of the cutting bit.

The tool is preferably made of steel alloy and the centre guide comprises a shanked slug, the shank being arranged to co-operate with the end of a coiled spring the external bore of which is arranged to fit within the internal bore of the bit of the tool.

The invention and its various features will be more readily understood from the following description which should be read in conjunction with the accompanying drawing.

The drawing shows that the tool comprises four component parts; a hollow shanked cutting bit 1, a spring 2, a centre guide 3, and a depth guide 4.

The bit 1 and centre guide 3 are made of EN24 steel alloy tempered in manufacture, while the depth guide 4 is made of nylon. The cutting bit is provided with a drill chuck co-operating shank 11 at one end and a hollow toothed cutting end 12.

The cutting end 12 carries a pair of cutting teeth and these are shown enlarged in the inset on the drawing at 13. The hollow section of the bit also includes a narrow vertical clearance slot.14 which is used to allow drilled-out material to be "vented" from the hollow section. The centre guide 3 includes a pointed end section and a shanked end arranged to be accommodated within the end turn of the spring 2. The spring 2 is arranged so as to ensure accurate contact of the tool to the work when an initial cut is being made. To use the tool the following procedure is used. The depth guide 4 includes a grub screw 41 for use in locating and fixing the guide to the hollow section of the bit.

Other Tools Required i. Electric drill, 9" chuck, preferably 2 speed.

ii. Centre punch.

iii. " plug-cutting bit.

Procedure i. Centre-punch remains of the screw or item to be removed if it is flush with or broken below surface of the wood. If the screw has broken off well down, or is countersunk, centre punching may not be necessary.

ii. With the cutter 1 in the drill, fit the spring 2 loaded centre guide 3 and locate the point in the punch mark or screw hole.

iii. With steady pressure on the drill to retain the centre guide 3 in position, make a guide cut (the spring 2 loaded guide 3 will retract 2111 to give an initial cut of about Tll) using low drill speed (1200 rpm).

iv. Remove the centre guide 3 from the cutter and fit the depth guide 4 if necessary. Note: this is not a depth stop - using it as such may result in damage to any surrounding finish.

v. Complete the cut to the required depth~ just clear of the estimated length of the screw.

Don't try to cut in one - take the pressure off the 111 drill for a second or two every 41' or so. The core containing the broken screw may come out with the cutter in which case it is removed with a punch or screwdriver through the clearance slot. If the core remains in the work, a small screwdriver may be used to loosen it making sure that the blade is inserted well down the side of the core so that the clean edge of the hole is not damaged.

vi. Cut and fit a plug of matching wood.

By this method, not only broken screws but also small nails and panel pins may be removed from even a finished job with the minimum of damage and refinishing required.

Typically the tool is some 75 mm in length having an internal hollow bit bore of one centimeter.

The above description has been of one explanatory embodiment only and alternative arrangements will readily be appreciated by those skilled in the art. For example, the tool could be used to remove other "blemishes" from wood, such as knots and the like, and the tool is not exclusively for use with the removal of screws etc.

from wooden surfaces; certain plastics finished surfaces may be operated upon using the tool according to the invention. Although it has been found in practice that only two teeth are required for the hollow cutting end of the tool additional teeth could be provided if required.

1. Wood-working tool or the like for use with a drill comprising (i) a drill chuck co-operating shaft, (ii) a hollow cutting bit and (iii) a spring loaded centre guide adapted to be removably located in the centre bore of the cutting tool and arranged to ensure accurate contact of the tool with a work surface in use.

2. A wood-working tool or the like according to claim 1 in which the hollow cutting bit includes a clearance slot adapted to vent drilled-out material from the inside of the hollow cutting bit.

3. A wood-working tool or the like according to claim 1 or 2 in which a depth guide is provided adapted to co-operate with the outside of the hollow cutting bit and arranged to be fixedly attached thereto.

4. A wood-working tool or the like substantially as herein before described with reference to the accompanying drawing.

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

Claims (4)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Wood working tool The present invention relates to a woodworking tool or the like and is more particularly concerned with a tool for removing broken screws, embedded panel pins and the like from wooden or similar surfaces. According to the invention there is provided a wood-working tool or the like for use with a drill comprising (i) a drill chuck co-operating shaft, (ii) a hollow cutting bit and (iii) a spring loaded centre guide adapted to be removably located in the centre bore of the cutting bit. The tool is preferably made of steel alloy and the centre guide comprises a shanked slug, the shank being arranged to co-operate with the end of a coiled spring the external bore of which is arranged to fit within the internal bore of the bit of the tool. The invention and its various features will be more readily understood from the following description which should be read in conjunction with the accompanying drawing. The drawing shows that the tool comprises four component parts; a hollow shanked cutting bit 1, a spring 2, a centre guide 3, and a depth guide 4. The bit 1 and centre guide 3 are made of EN24 steel alloy tempered in manufacture, while the depth guide 4 is made of nylon. The cutting bit is provided with a drill chuck co-operating shank 11 at one end and a hollow toothed cutting end 12. The cutting end 12 carries a pair of cutting teeth and these are shown enlarged in the inset on the drawing at 13. The hollow section of the bit also includes a narrow vertical clearance slot.14 which is used to allow drilled-out material to be "vented" from the hollow section. The centre guide 3 includes a pointed end section and a shanked end arranged to be accommodated within the end turn of the spring 2. The spring 2 is arranged so as to ensure accurate contact of the tool to the work when an initial cut is being made. To use the tool the following procedure is used. The depth guide 4 includes a grub screw 41 for use in locating and fixing the guide to the hollow section of the bit. Other Tools Required i. Electric drill, 9" chuck, preferably 2 speed. ii. Centre punch. iii. " plug-cutting bit. Procedure i. Centre-punch remains of the screw or item to be removed if it is flush with or broken below surface of the wood. If the screw has broken off well down, or is countersunk, centre punching may not be necessary. ii. With the cutter 1 in the drill, fit the spring 2 loaded centre guide 3 and locate the point in the punch mark or screw hole. iii. With steady pressure on the drill to retain the centre guide 3 in position, make a guide cut (the spring 2 loaded guide 3 will retract 2111 to give an initial cut of about Tll) using low drill speed (1200 rpm). iv. Remove the centre guide 3 from the cutter and fit the depth guide 4 if necessary. Note: this is not a depth stop - using it as such may result in damage to any surrounding finish. v. Complete the cut to the required depth~ just clear of the estimated length of the screw. Don't try to cut in one - take the pressure off the 111 drill for a second or two every 41' or so. The core containing the broken screw may come out with the cutter in which case it is removed with a punch or screwdriver through the clearance slot. If the core remains in the work, a small screwdriver may be used to loosen it making sure that the blade is inserted well down the side of the core so that the clean edge of the hole is not damaged. vi. Cut and fit a plug of matching wood. By this method, not only broken screws but also small nails and panel pins may be removed from even a finished job with the minimum of damage and refinishing required. Typically the tool is some 75 mm in length having an internal hollow bit bore of one centimeter. The above description has been of one explanatory embodiment only and alternative arrangements will readily be appreciated by those skilled in the art. For example, the tool could be used to remove other "blemishes" from wood, such as knots and the like, and the tool is not exclusively for use with the removal of screws etc. from wooden surfaces; certain plastics finished surfaces may be operated upon using the tool according to the invention. Although it has been found in practice that only two teeth are required for the hollow cutting end of the tool additional teeth could be provided if required. CLAIMS

1. Wood-working tool or the like for use with a drill comprising (i) a drill chuck co-operating shaft, (ii) a hollow cutting bit and (iii) a spring loaded centre guide adapted to be removably located in the centre bore of the cutting tool and arranged to ensure accurate contact of the tool with a work surface in use.

2. A wood-working tool or the like according to claim 1 in which the hollow cutting bit includes a clearance slot adapted to vent drilled-out material from the inside of the hollow cutting bit.

3. A wood-working tool or the like according to claim 1 or 2 in which a depth guide is provided adapted to co-operate with the outside of the hollow cutting bit and arranged to be fixedly attached thereto.

4. A wood-working tool or the like substantially as herein before described with reference to the accompanying drawing.