AU759411B2 - Jig for use in sharpening cutting implement for use in wood turning - Google Patents

Description

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION STANDARD PATENT Jig for use in Sharpening Cutting Implement for use in Wood turning The following statement is a full description of this invention, including the best •method performing it known to me: Q0 5 FIELD OF THE INVENTION The following invention relates to a jig for use in sharpening cutting implements, typically for use in wood turning and/or wood carving. More particularly, though not

*S.S

exclusively, the invention relates to a jig for supporting and guiding a spindle and/or detail gouge enabling interaction of the gouge with a grinding wheel so as to provide a desirable fingernail shape at the sharpened end of the gouge. The invention also go relates to such a jig which can also be used to sharpen a gouge such as a bowl gouge, roughing gouge, Euro spindle gouge, carving chisels and carving gouge.

o• It is known to manually support a gouge upon a support bar in front of a grinding wheel and to move the gouge using a fanning action during sharpening. This provides a less than ideal profile at the sharpened end of the gouge. In order to provide the desired fingernail shape at the end of the gouge, a "rotate and push method" ought to be adopted. That is, the gouge ought to be rotated only about its longitudinal axis while being pushed along that axis toward the grinding wheel. A fingernail profile as so produced provides a desirable cutting effect when engaged with a piece of wood being turned upon a lathe.

It is known to perform the rotate and push method manually. However, it takes a skilled operator to achieve the desired result.

2 OBJECT OF THE INVENTION It is the object of the present invention to overcome or substantially ameliorate the above disadvantages and/or more generally to provide a jig for use in sharpening a cutting implement such as a gouge for use in wood turning and/or wood carving.

DISCLOSURE OF THE INVENTION There is disclosed herein ajig including: a tubular housing having opposed ends and a guide surface, the housing being mountable nearby a grinder, oooo a tool holder located by and guided within said housing so as to be pivotable •.about a longitudinal axis of said housing and slidable along said longitudinal axis, the tool holder having attachment means to secure a tool thereto such that part of the tool .i 15 passes through said housing so as to present a tip of the tool toward the grinder, said tool holder further having a guide boss engageable with said guide surface such that throughout engagement a correlation exists between linear movement of the tool along said longitudinal axis and pivotal movement of the tool about said longitudinal axis, so as to enable a desired, controlled interaction between the tip of the tool and the grinder.

Preferably the grinder is a grinding wheel and the housing is pivotally mounted nearby the grinding wheel about an axis which is parallel with the rotational axis of the grinding wheel.

Preferably the guide surface of the tubular housing is annular and is at one of said opposed ends thereof.

Preferably the housing has two annular guide surfaces, one at each opposed end thereof.

Preferably one of said guide surfaces is planer, being in a plane normal to the longitudinal axis of the housing.

Preferably the other guide surface is at an acute angle with respect to the longitudinal axis of the housing. Alternatively, this other guide surface can be contoured, curved, staggered, stepped or otherwise formed.

Preferably the attachment means of the tool -holder includes one or more threaded apertures through which bolts can be received, the bolts extending radially of the longitudinal axis of the housing and being tightenable upon the tool.

Where two guide surfaces are provided, two guide bosses are provided, each boss "being engageable, one at a time, with a respective one of said guide surfaces.

Typically, the tool is a gouge for use in wood turning or wood carving.

S Where the gouge is a spindle and/or detail gouge for example, it can be sharpened using the above jig by engagement of one of said guide bosses along said acutely angled guide surface.

Where the gouge is a bowl gouge, Euro spindle gouge, roughing gouge, carving chisel ~or carving gouge, the other of said guide bosses is typically engaged with the other guide surface, ie. the guide surface in a plane normal to the longitudinal axis of the housing. That is, a rotational action only is required when sharpening a bowl gouge whereas a combined rotational and longitudinal motion is required when sharpening a spindle and/or detail gouge.

There is further disclosed herein a method of sharpening a gouge, the method including the steps of: attaching the gouge to the tool holder of the above-disclosed jig such that the gouge passes through said housing with an end of the gouge presented to the grinder, pivoting the gouge about its longitudinal axis such that the tool holder pivots and slides linearly within the tubular housing whilst maintaining contact of said guide boss with said guide surface.

BRIEF DESCRIPTION OF THE DRAWINGS A preferred form of the present invention will now be described by way of example with reference to the accompanying drawings, wherein: Fig. 1 is a schematic elevational view of a jig for use in sharpening cutting implements for use in wood turning; ••Fig. 2 is a schematic elevational view of a housing, forming part of the jig of .1 Fig. 1; Fig. 3 is a schematic end elevational view of the housing of Fig. 1; Fig. 4 is a schematic plan view of the housing of Figs. 2 and 3; S 15 Fig. 5 is a schematic plan view of a tool holder, forming part of the jig of Figs.

1 to 3; ~Fig. 6 is a schematic elevational view of the jig of Fig. 1 mounted upon a post alongside a grinding wheel, the jig supporting a tool being sharpened against the •grinding wheel; Fig. 7(a) is a schematic plan view of a spindle and/or detail gouge; Fig. 7(b) is a schematic side elevational view of the gouge of Fig. 7(a); Fig. 8 is a schematic side elevational view of a spindle and/or detail gouge having an undesirable contour as produced by a fanning action upon a grinding wheel; Fig. 9 is a schematic plan view of a spindle and/or detail gouge having a desirable "fingernail" contour as produced by the jig as disclosed herein; Fig. 10 is a schematic end elevational view of a bowl gouge; Figs. 11, 12 and 13 are schematic cross-sectional end elevational views of a number of different gouge sometimes known as Euro spindle gouges or roughing gouges; and Fig. 14 is a schematic side elevational view of the tip portion of a bowl gouge as sharpened using the jig of Fig. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT In Fig. 1 of the accompanying drawings there is schematically depicted a jig 10 for use in sharpening a gouge of the type used in wood turning.

The jig 10 includes a cast metallic housing 12 which includes a leg 16 by which the housing 12 can be pivotally mounted by means of an axle passing through pivot hole 17. The housing 12 has a passage extending therethrough which has a circular crosssection. As an alternative to casting the housing 12 integrally with the leg 16, two separate pieces of metal pipe can be welded together to provide the tubular body and pivot hole 17.

Located within the housing 12 and adapted to slide smoothly therein is a tubular tool holder 11. Tool holder 11 is typically formed from a length of metallic pipe. The outer o 15 diameter of the tool holder 11 is to be slightly less than the inner diameter of the passage passing through the housing 12 so as to enable smooth, yet guided, free Smovement of the tool holder 11 within the housing 12.

At the left hand end of the housing 12, there is provided an angled guide surface 13.

The angle of the guide surface with respect to the longitudinal axis A of the housing 12 is typically in the range of 300 to 600 but is more typically 400. As an alternative to a fixed angle, the surface 13 might be curved, contoured, stepped or otherwise formed, depending on the type of tool being sharpened or the desired sharpening profile to be achieved at the tool tip. At the other, right hand end of housing 12, there is another guide surface 31, which in this instance resides in a plane that is normal to the longitudinal axis A of the housing 12.

The tool holder 11 includes a forward boss 14 and a rear boss 15. The forward boss 14 is adapted to ride against the angled guide surface 13 when the tool holder 11 is rotated about axis A. That is, so long as the forward boss 14 is maintained in contact with the guide surface 13 when the tool holder 11 is pivoted about axis A, the tool holder 11 will be caused to transfer along axis A in a defined and controlled manner.

In this way, the position of the tool along axis A is allied with the pivotal orientation of the holder about axis A.

Similarly, if the rear boss 15 is maintained in contact with the guide surface 31 during pivotal movement of the tool holder 11, no transfer of the tool holder 11 along axis A results.

The tool holder 11 includes a pair of internally threaded apertures 18, each of which receives a bolt 23 (Fig. 6) which bears down upon the shaft or blade of a gouge 22. As shown in Fig. 6, a gouge 22 includes a handle 21. The. blade of the gouge 22 passes °°through the tool holder 11 within which it is retained by bolts 23.

Also as shown in Fig. 6, the housing 12 is pivotally mounted upon a post 24, the base S* 25 of which is typically secured to a workbench top 26. Also upon this workbench would be a grinding wheel 27 against which the tip of the tool shaft 22 is sharpened.

The grinding wheel 27 is typically driven by an electric motor so as to rotate about axis B.

Figs. 7(b) and 9 show the desired "fingernail" contour at the sharpened end of a spindle and/or detail gouge produced by a "rotate and push method" achieved by use the jig 10 with forward boss 14 maintained in contact with guide surface 13.

Fig. 8 on the other hand shows an undesirable contour formed at the end of a sharpened spindle and/or detail gouge using a manual "fanning action".

To produce the "fingernail" contour, the following procedure can be adopted.

Firstly it should be ensured that the vertical post 24 is parallel with the sides of the grinding wheel 11.

To determine the shape of the desired fingernail gouge, the top cutting edge thereof is first placed gently on the side of the grinding stone. A small amount of material is then ground away off both cutting edges. This will achieve the shape to which grinding will be made.

With the grinder not running, the gouge blade 22 is clamped into the tool holder 11 by means of bolts 23. A desired length of the blade 22 should protrude from the front end of the tool holder. The handle 2 lof the gouge should then be manoeuvred until the tip of the blade 22 touches the grinding wheel 27. Then looking from the side, all the hollow ground bevel of the tool should be in contact with the grinding stone. If not, the locking bolt 32 should be slackened to enable the post 24 to be pivoted forward or back until the bevel is in contact with the stone. Rotation of the gouge about axis A can be performed by manipulating handle 21. At the same time, if the forward boss 14 should be maintained in contact with the guide surface 13. Rotating the gouge to the right and left projects the gouge blade 22 forward and backwards to give the desired sharpening effect. Of course, at this time, the grinding wheel 27 is rotating. There is 0 no need to force the jig 10 in any way, but simply to maintain contact between boss 14 and guide surface 13. A forwards and backwards pivoting motion should be 0 •maintained until the operator has removed the flats which define the required shape.

To sharpen a bowl gouge, roughing gouge, Euro spindle gouge or a wood carving chisel or gouge, it is clamped into position within the tool holder as described above.

However, instead of maintaining pin 14 in contact with guide surface 13, pin 15 is to be maintained in contact with guide surface 31. For a bowl gouge, only a rotating action is required, ie. no forward and backward movement is necessary. The desired end result or contour is as shown in Fig. 14.

It should be appreciated that modifications and alterations obvious to those skilled in the art are not to be considered as beyond the scope of the present invention. For example, instead of providing guide surfaces at opposed ends of housing 12, appropriate slots might be provided in the housing. The slots might pass the whole way through the housing sidewall, or might be formed in the internal surface thereof.

Claims (12)

1. A jig including: a tubular housing having opposed ends and a guide surface, the housing being mountable nearby a grinder, a tool holder located by and guided within said housing so as to be pivotable about a longitudinal axis of said housing and slidable along said longitudinal axis, the tool holder having attachment means to secure a tool thereto such that part of the tool passes through said housing so as to present a tip of the tool toward the grinder, said tool holder further having a guide boss engageable with said guide surface such that •°throughout engagement a correlation exists between linear movement of the tool along .i said longitudinal axis and pivotal movement of the tool about said longitudinal axis, so as to enable a desired, controlled interaction between the tip of the tool and the grinder.

2. The jig of claim 1 wherein the grinder is a grinding wheel grinding wheel and the housing is pivotally mounted nearby the grinding wheel about an axis which is parallel with the rotational axis of the grinding wheel.

3. The jig of claim 1 or claim 2 wherein the guide surface of the tubular housing is annular and is at one of said opposed ends thereof

4. The jig of claim 1 or claim 2 wherein the housing has two annular guide surfaces, one at each opposed end thereof.

The jig of claim 4 wherein one of said guide surfaces is planer, being in a plane normal to the longitudinal axis of the housing.

6. The jig of claim 5 wherein the other guide surface is at an acute angle with respect to the longitudinal axis of the housing. 9

7. The jig of claim 5 wherein the other guide surface is contoured, curved, staggered, stepped or otherwise formed.

8. The jig of any one of the preceding claims wherein the attachment means of the tool holder includes one or more threaded apertures through which bolts can be received, the bolts extending radially of the longitudinal axis of the housing and being tightenable upon the tool.

9. The jig of any one of claims 4, 5, 6 or 7 wherein two guide bosses are provided, each boss being engageable, one at a time, with a respective one of said guide surfaces.

10. A method of sharpening a gouge using the jig of claim 1, the method including the steps of: attaching the gouge to the tool holder such that the gouge passes through said housing with an end of the gouge presented to a grinder, pivoting the gouge about its longitudinal axis such that the tool holder pivots and slides linearly within the tubular housing whilst maintaining contact of said guide boss with said guide surface.

11. A jig substantially as hereinbefore described with reference to Figures 1 to 8 of S"the accompanying drawings.

12. A method of sharpening a gouge, the method being substantially as hereinbefore described with reference to the accompanying drawings. DATED this 5th day of April 2000 MICHAEL IRVINE JOHN ARTHUR CRAWFORD Patent Attorneys for the Applicants: HALFORD CO