Wood working tool

A cutter to be mounted on a spindle of a rotary tool for use in shaping timber. The cutter comprising a rigid member to be mounted co-axially on the tool spindle to rotate therewith and having a plurality of spaced cutting teeth about the periphery of the member, each tooth having a cutting edge extending in a direction transverse to the plane of rotation of the member, and a cutting edge extending in a direction generally radial to the axis of rotation of the member. A depth control projection in advance of each tooth to control the depth of cut of both the transverse and radial cutting edges.

This invention relates to a wood working tool for wasting and shaping wood. 
In recent years wood sculpture and free form furniture have become popular. 
Conventionally a chain saw is used in the initial wasting the timber to 
form a general shape which is then refined with a chisel and like hand 
tool. In using a chain saw the nose portion is used and, because the nose 
portion is remote from the handles of the saw, control of the cutting is 
difficult. Lateral movement of the nose portion is not possible partly 
because of the presence of the bar supporting the cutting chain, and 
mainly because the cutting teeth of a chain saw do not have an 
appropriately positioned cutting edge with the necessary relief to cut 
when moved laterally. Thus, when a chain saw is used, considerable 
material is left to be removed by a chisel. The chisel work is relatively 
slow and laborious. Grinding discs may be used for finishing wasting 
operations, but these are also slow, and readily produce burning that 
discolours the timber. 
It is an object of the present invention to provide a power tool cutter 
which can perform part of the wasting usually carried out by the chainsaw 
and the chisels, and is convenient and safe to use. 
To this end the present invention provides a cutter to be mounted on a 
spindle of a rotary tool, said cutter comprising a rigid member adapted 
for mounting co-axially on the tool spindle to rotate therewith, a 
plurality of spaced cutting teeth about the periphery of the member, at 
least some of said cutting teeth having a cutting edge extending in a 
direction transverse to the plane of rotation of the member, and at least 
some of the teeth having a cutting edge extending in a direction generally 
radial to the axis of rotation of the member. 
Preferably the transverse and radial cutting edges are provided on the same 
cutting teeth. Conveniently cutting depth control projections are provided 
to limit the depth of cut, at least of the transverse cutting edges, as 
excessive depth of cut may produce a "kick-back" action, similar to that 
experienced with a conventional chain saw. The depth control projection 
may be in the form of a generally radial projection from the peripheral 
edge of the rigid member in advance, with respect to the direction of 
rotation of the cutter, of each lateral cutting edge. The depth of the cut 
that the transverse cutting edge may make is the difference between the 
radial distance of the transverse cutting edge from the rotational axis 
and the radial distance of the tip of the depth control projection from 
that axis. 
The same depth control projection may be positioned in a spaced relation to 
the radial cutting edge to control the depth of cut of the radial cutting 
edge, as the depth of cut control projection for the transverse cutting 
edge extends in the radial direction from the periphery of the rigid 
member, and so presents a radial face. The depth of cut of the radial 
cutting edge is controlled by the distance between the radial cutting edge 
and this radial face of the projection, measured in the direction parallel 
to the axis of rotation. 
It is conventional in saws for the cutting teeth to be alternately offset 
in opposite direction from the saw blade upon which the teeth are mounted 
to provide clearance for the saw blade. This same offset arrangement is 
incorporated in the cutter according to the present invention, however in 
some forms of the cutter, all of the teeth may be offset to one side only 
of the plane of the cutter. 
The arrangement of the cutting edges on the cutting teeth, as proposed by 
the present invention, enable the cutter to cut when moved into a piece of 
timber in the plane of rotation of the cutter and generally at right 
angles to the surface of the timber in the manner of a conventional saw. 
However the present cutter may also be moved in either direction normal to 
the plane of the cutter. Further the present cutter may be used with the 
plane of rotation of the cutter presented generally parallel or slightly 
inclined to the timber surface to be cut, and in this attitude may be 
moved in any direction across the timber surface, which is not possible 
with a conventional saw, including a chain saw. Also the present cutter 
may effect a combination of these movements to provide contoured surfaces 
which is also not possible with a chain saw or other saws. 
Thus the operator may, using a power tool fitted with the cutter of the 
present invention, rapidly gouge large quantities of timber and so shape 
large areas in a relatively short time, and with little effort. In 
particular single and compound curved surfaces can be produced simply, and 
with a finish requiring a reduced amount of subsequent fine finishing and 
sanding. 
Conventional disc type cutting power tools do not permit lateral movement 
and thus cannot function as gouging tools. The effectiveness of the cutter 
of this invention in lateral gouging is partly related to speed of 
rotation and to the spacing of the teeth, but is primarily derived from 
the form of the cutting teeth.

Referring now to FIGS. 2 to 4, the cutter disc 3 is of a dished form having 
a central planar portion 5 and an integral flaired portion 2. 
The central portion 5 has a co-axial attachment hole 4, which receives the 
spindle of a suitable power tool, or a bolt or the like that attaches the 
cutter to the power tool spindle. The axial depth from the central portion 
5 to the outer perimetal edge 6 of the flaired portion 2, enable a nut or 
bolt head, that secures the disc to the spindle of the power tool, to be 
below the perimetal edge 6. 
Equally spaced around the perimetal edge 6 are the six cutting teeth 7 each 
having a lateral cutting edge 8, transverse to the plane of the perimetal 
edge 6, and a generally radial cutting edge 9. The radial cutting edge is 
of an arcuate shape but effects a cut generally in the radial direction 
with respect to the plane of the rotation of the perimetal edge 6 of the 
cutter. The alternate teeth are offset in opposite directions from the 
plane of the perimetal edge 6, as is conventional in saws, so the radial 
cutting edges 9 are resultantly slightly inclined to that plane. 
The cutting teeth 7 are generally of a construction similar to the cutting 
teeth of a chain saw, having a peripheral land 10 extending rearwardly 
from the transverse cutting edge 8 and inclined inwardly so as to be 
within the circle described by transverse cutting edge 8 as the cutter 
rotates to provide relief or clearance. These features of the cutting 
teeth are more clearly seen in FIG. 4. Further, as seen in FIG. 5, the 
radial land 20 is inclined inwardly from the radial cutting edge 9 toward 
the plane of the cutter to also provide relief or clearance in the 
direction of rotation. Clearance in this form is not provided on a 
conventional chain saw tooth, but is required on the teeth of the present 
cutter to render the radial cutting edge fully effective. The inclination 
of the land 20 as seen in FIG. 5, extends inwardly over the full extent of 
the inclined portion 22 of the tooth on which the radial cutting edge 9 is 
formed. This enables the radial cutting edge of the cutter to effectively 
cut when being operated to move in the direction D as shown in FIG. 6. 
Depth control projections 12 are provided forward of each transverse 
cutting edge 8 as also shown in FIG. 4. The tip 11 of the projection 12 is 
on a radius less than that of the transverse cutting edge 8, the 
difference in radius determining the depth of the cut made by each 
transverse cutting edge as indicated at 13 in FIG. 6. The portion 15 of 
the depth control projection 12 is displaced from the radial cutting edge 
9 in the axial direction, that displacement sets the depth of cut of the 
radial cutting edge as indicated at 14 in FIG. 6. 
When the cutter 3 is mounted on the spindle of a rotary tool, such as an 
angle grinder 24 as shown in FIG. 1, it is possible to easily gouge and 
waste a piece of timber in directions in the plane of rotation of the 
cutter, when that plane is either normal or parallel to the surface to be 
worked, and moved in any direction across that surface. Typical directions 
of movement of the cutter are indicated by arrows in FIG. 1. The finish 
achieved is superior to that of a chisel and is achieved in a much shorter 
time. 
Because the disc, carrying the cutting teeth, is centrally mounted on the 
power tool spindle, it is possible to provide on the tool a grip close to 
the cutting teeth, as indicated at 23 in FIG. 1, so that a high degree of 
manual control can be exerted over the cutting depth and movement. 
When the disc is of the dished form as described with reference to FIGS. 2 
and 3 of the drawings, there are some limitations in regard to the shapes 
which may be formed by the use of the cutter. It is therefore also 
proposed that the cutter may be in a form with cutting teeth carried on a 
peripheral flange of a generally cylindrically shaped cutter body. Such a 
cutter is illustrated in FIG. 7 of the drawings. The cylindrical portion 
21 is of considerably less diameter than the dished cutter 2 shown in 
FIGS. 2 and 3, and also the overall diameter of the peripherally arranged 
cutting teeth 7 is considerably less than that of the cutting teeth shown 
in FIGS. 2 and 3. In this construction the end 18 of the cylinder remote 
from the cutting teeth 7 maybe closed with a central opening to receive 
the spindle of a power tool, or, alternatively, as shown, the closed end 
18 of the cylinder incorporates a nut 16 secured to the cylinder 21 by the 
swaged portion 17. The nut is internally threaded so that it may be 
connected in threaded engagement with a threaded section of the spindle of 
the power tool. If desired, a locking nut may also be provided to 
co-operate with the nut 16 in the conventional locking nut relationship. 
The provision of a threaded nut, integral with the cutter, as above 
described, may also be incorporated in the dished cutter, such as that 
previously described with reference to FIGS. 2 and 3, or into any other 
form which the cutter may take. 
In the construction shown in FIG. 7 the cutting teeth 7 are formed on a 
peripheral flange 19 disposed radially to the axis of the cylinder, 
however, the flange and the cutting teeth thereon may be inclined to the 
cylinder axis. 
In a further modification to the previously described cutter, the depth 
control projection 12 provided in advance of each cutting tooth, as 
previously described with reference to FIGS. 2 and 5, may be omitted from 
the construction of the cutter and the depth of cut is then left to be 
controlled in accordance with the skill of the operator. Where a depth 
control projection is not provided in association with each cutting tooth, 
it is desirable to reduce the pitch of the teeth so that each tooth will 
act in the manner of a depth control for the immediately following tooth, 
when considered in the direction of rotation of the cutter. A typical form 
of such tooth is shown diagrammatically in FIG. 8 of the accompanying 
drawings. 
Preferably the disc 2 and cutting teeth 7 are of an integral construction 
as shown, and formed by stamping from a metal sheet. Alternatively the 
teeth 7 can be detachably fitted to the rim of the disc so that teeth of 
varying shapes can be interchanged. It is also possible to simply weld 
suitably formed cutting teeth to the periphery of a disc. 
In one detachable tooth form, the teeth are provided with one or more 
apertures to enable each tooth to be fitting onto a corresponding number 
of pins provided on a disc adjacent the periphery thereof. Conveniently, a 
further clamp disc is provided, having apertures to also receive said 
pins, where, by axially clamping the discs together, the teeth are gripped 
therebetween and held in assembly on the pins. 
In this specification, specific reference has been made to the use of the 
cutter in working timber, but it is to be understood it may also be used 
on many other materials, including plastics, rubbers, soft stone and soft 
metals such as lead and zinc. 
From the above it can be seen that this invention provides a unique wood 
working cutter, that may be used to produce intricate curved surfaces 
quickly and acurately. The cutter may be used to cut in any direction 
independent of the direction of the grain of the timber. The operator has 
a high degree of control over the cutter when used in conjunction with a 
hand held angle grinder tool, and so is safe and accurate in operation. 
The finish resulting from the use of the tool requires a minimum of 
further working prior to sanding to a final finish. The cutter produces 
chips rather than dust and is therefore more environmentally acceptable. 
The tool may also be used for producing straight cuts, grooves, notches or 
trenches, and is therefore useful in the construction industry. 
The claims defining the invention are as follows.