Improved Rotary Milling Cutters for Grooving and Tongueing of Boards and the like.
Year: 1898

page_text: Improved Rotary Milling Cutters for Grooving and Tongueing of
Boards and the like.
I, ANDERS AUGUST WESTMAN, of 21, Gamla Kungsholmsbrogatan, Stockholm,
Sweden, Mechanical Engineer, do hereby declare the nature of this invention
to be as follows:-
Grooving and tongueing of boards, and the like are well known to be accomplished
by means of rotating milling-cutters, the edges of which have a shape corre-
sponding to the section of the groove and tongue to be formed. If the groove
and tongue, as heretofore customary, are given parallel sides, it is necessary, in
order to prevent the cutter becoming wedged to the work or the creation of a
considerable frictional resistance, to make the thickness of the teeth smaller in
the rear of the cutting-edge, an arrangement involving the disadvantage that the
edges cannot be sharpened by grinding off the forward surfaces of the teeth, since
the shape of the edges would be changed in so doing.
In order to enable the sharpening of the edges of the milling-cutter while at the
same time retaining their shape, the teeth of said cutters, in accordance with this
invention, are not provided with edges of the usual rectangular shape, but their
side-edges are instead made to form an angle with each other and the metal in the
rear of the edges given an eccentrically-located surface composed of two
conefragments.
In the accompanying drawing two cutters for milling grooves and tongues to
match are shown, as arranged in accordance with this invention. Figs. 1 and 2
show respectively an elevation of the grooving-cutter (partly in section) and a plan-
view of same, while Figs. 3 and 4 show the corresponding views of the tongueing
cutter.
The outer edges of the cutter-teeth a, b, are given an eccentric position. It
is seen from Fig. 1 that the backs a¹ of the teeth are wedge-shaped or bounded
at their sides by conical surfaces while, as seen from Fig. 2, the teeth 6 of
the tongueing-cutter have grooves of corresponding shape. The forward end of
each tooth forms a plane surface a², 62, making an acute angle with the outer
edge. Said surfaces together with the eccentric edges of the teeth, form the
working edges.
When using a cutter of this kind a clearance-space is formed during the rotation

page_text: behind the edges, between the eccentric surfaces of the teeth and the material
operated on, and consequently, no undue frictional resistance will be created.
When the edges become dulled, they can be sharpened simply by grinding the
plane, surfaces a², 62, and by this operation the shape of the edges will not be
changed, owing to the fact that in the rear of said edges the teeth are of uniform
thickness at equal distances from the outer edge.
The back, or groove, of the cutter-teeth need only be slightly wedge-shaped,
although for greater clearness the conical surfaces are represented in the drawing as
having a greater inclination.
The use of cutters of this kind in place of the cutters with detachable blades,
as heretofore customary, is especially advantageous on account of the possibility
of operating on the material uniformly with all the edges since the latter will always
be at the same distance from the centre.
Dated this 23rd day of Anril 1898
CRUIKSHANK & FAIRWEATHER,
Chartered Patent Agents, 62, Saint Vincent Street, Glasgow
Agents for the Applicant.
Improved Rotary Milling Cutters for Grooving and Tongueing of
Boards and the like.
I, ANDERS AUGUST WESTMAN, of 21, Gamla Kungsholmsbrogatan, Stockholm,
Sweden, Mechanical Engineer, do hereby declare the nature of this invention
and in what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement:-
Grooving and tongueing of boards and the like are well known to be accomplished
by means of rotating milling-cutters, the edges of which have a shape corre-
sponding to the section of the groove and tongue to be formed. If the groove
and tongue, as heretofore customary, are given parallel sides, it is necessary, in
order to prevent the cutter becoming wedged to the work or the creation of a
considerable frictional resistance, to make the thickness of the teeth smaller in
the rear of the cutting-edge, an arrangement involving the disadvantage that the
edges cannot be sharpened by grinding off the forward surfaces of the teeth, since
the shape of the edges would be changed in so doing.
In order to enable the sharpening of the edges of the milling-cutter while at the
same time retaining their shape, the teeth of said cutters, in accordance with this
invention, are not provided with edges of the usual rectangular shape, but their
side-edges are instead made to form an angle with each other and the metal in the
rear of the edges is given an eccentrically-located surface composed of two
conefragments.
Referring to the drawings filed with the Provisional Specification, two cutters
for milling grooves and tongues to match are shown, as arranged in accordance
with this invention. Figs. 1 and 2 show respectively an elevation of the grooving-
cutter (partly in section) and a plan-view of same, while Figs. 3 and 4 show the
corresponding views of the tongueing-cutter.
The outer edges of the cutter-teeth a, b, are given an eccentric position. It
is seen from Fig. 1 that the backs a¹ of the teeth are wedge-shaped or bounded
at their sides by conical surfaces while, as seen from Fig. 3, the teeth b of
the tongueing-cutter have grooves of corresponding shape. The forward end of
each tooth forms a plane surface a², 62, making an acute, angle with the outer

page_text: edge. Said surfaces together with the eccentric edges of the teeth, form the
working edges.
When using a cutter of this kind a clearance-space is formed during the rotation
behind the edges, between the eccentric surfaces of the teeth and the material
operated on, and consequently, no undue frictional resistance will be created.
When the edges become dulled, they can be sharpened simply by grinding the
plane surfaces a, b, and by this operation the shape of the edges will not be
changed, owing to the fact that in the rear of said edges the teeth are of uniform
thickness at equal distances from the outer edge.
The back, or groove, of the cutter-teeth need only be slightly wedge-shaped,
although for greater clearness the conical surfaces are represented in the drawing as
having a greater inclination.
The use of cutters of this kind in place of the cutters with detachable blades,
as heretofore customary, is especially advantageous on account of the possibility
of operating on the material uniformly with all the edges since the latter will always
be at the same distance from the centre.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, 1 declare that what
I claim is:
In rotary milling-cutters for grooving and tongueing boards and the like, the
arrangement that the teeth (a, b) of the cutter are provided with an eccentric
back (a), or groove (b) to match, which is wedge-shaped or bounded at its sides
by conical surfaces, for the purpose of causing the teeth during this rotation,
immediately on leaving the point of tangency of the cutter and the board, to
recede from the lateral surfaces of the tongue or groove respectively, in spite of the
fact that the teeth (at equal distances from their outer edge) have a uniform
thickness of metal in order to allow of the edges being sharpened by grinding the
forward, plane surfaces of the teeth.
1000
CRUIKSHANK & FAIRWEATHER,
Chartered Patent Agents, 62, Saint Vincent Street, Glasgow,
Agents for the Applicant.