Note: Descriptions are shown in the official language in which they were submitted.
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This invention relates to a tool for rotat~bly holding
a workpiece on the bed of a surface grinding machine, milling
machine or similar equipment.
Grinding machines, milling machines, and other similar
equipment require that the workpiece be adequately supported
on the bed of the machine by a "set-Up" which usually requires
a considerable amount of skilled labour to install. Such a
set-up must be built such that it remains accurately positioned
while the same operation is being performed on a series of
workpieces. One common set-up involves a means for rotatably
supporting a workpiece on the bed of the machine such that
the workpiece may be rotated to present different faces to the
cutting tool on the machine. Set-ups that allow rotation of
a workpiece while maintaining the workpiece in accurate
alignment are very expensive, and as mentioned, the installation
of such a set-up involves expensive labour costs. It would thus
be very advantageous if a rotary holding tool were devised
which minimized set-up labour costs and was very simple
to operate. The subject invention is such a tool; it incorporates
features of a number of presently expensive single function
tools with new features of its own, and can be produced at a very
reasonable price. In particular, the subject invention
incorporates the function of such tools as an indexing plate,
a turntable base, a radius dresser, a rotary table (horizontal
and vertical or tilting), and an index center, among others.
The subject invention is a rotary holding tool,
comprising a base member, a support member extending from the
base member, a rotary holding member rotatably mounted to the
support member such that its axis of rotation extends parallel
to the base member, and a releasable angular locking means
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adapted to releasably lock the rotary holdlng member and the
support member into a series of relative angular alignment
positions. A portion of the holding member is disc-shaped
with its symmetrical axis on the axis of rotation and has
graduated markings extending around its periphery to indicate
its angular displacement relative to the support member. The
releasable angular locking means comprises a sexies of apertures
on the rotary holding member, the apertures being positioned
at equal radial distances from the axis of symmetry of the
holding member and being spaced at equal angular intervals
therearound. The locking means also comprises a series of
fasteners on the support member, the fasteners being spaced
at equal angular intervals around the axis of symmetry of the
holding member and each fastener having a complementary fit
with any one of the apertures. The angular positioning of
the apertures and the fasteners is such and the number of
fasteners is such that when one of the fasteners fits into
one of the apertures none of the other fasteners can be
fitted into any other of the apertures. The angular separation
between adjacent fasteners isgreater than the angular
separation between adjacent apertures by an angular increment
equal to that between adjacent relative angular alignment
positions.
Each of the fasteners may be a pin slidable through
the support member and having its symmetrical axis extending
parallel to the axis of rotation of the rotary holding member, and
each of the apertures may be a bore extending parallel to the
axis of rotation of the rotary holding member, wherein each of the
relative angular alignment positions is defined by one of the
pins sliding axially to fit into one of the bores.
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The equal angular spacing between apertures may be
fifteen degrees and the equal angular ~pacing between fasteners
may be twenty degrees such that the angular spacing between
adjacent relative angular alignment positions is five degrees,
there being 72 alignment positions in such arrangement.
The rotation of the rotary holding member relative
to the support member may be limited to a range of angles,
the limited rotation resulting from engagement of a pin on
the support member with an annular groove extending angularly
around the rotary holding member, the length of the groove
defining the range of angles.
The invention will next be more fully described
by means of a preferred embodiment utilizing the accompanying
drawings wherein:
Figure 1 is a perspective view of the rotary holding
tool of the subject invention.
Figure 2 is a partially-sectioned side view of the
rotary holding tool of the subject invention.
Figure 3 is an end view of the rotary holding tool
of the subject invention.
; Figure 4 is a perspective view of the radius
dresser attachment of the subject invention and its position
relative to a grindstone prior to dressing.
Figure 5 is an end view of a dressed grindstone
and a workpiece contoured by the grindstone.
Figure 6 is a perspective view of the rotary holding
tool of the subject invention, wherein the tool is supported
such that its axis of rotation extends generally vertically.
Figure 7 is a bottom view of the rotary holding tool
of the subject invention.
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Eigure 8 is a side view of the rotary holding tool
of the subject invention as in Figure 2 but illustrating
replacement of the rotary holding member by a live centre.
Figure 9 illustrates a small sampling of the wide
variety of dies that may be formed utilizing the rotary holding
tool of the subject invention.
Figure 10 illustrates the rotary holding tool of the
subject invention positioned on the bed of a grinding machine.
Referring to Figure 1, the rotary holding tool is
generally designated as 11 and comprises an interchangeable base
member 12, a support member 13 secured at right angles to base
member 12, a rotary holding member rotatably mounted to the
support member 13 and generally designated as 14, and releasable
angular locking means generally designated as 15. It may
additionally comprise a second support member 16 tc better
support a workpiece held in the rotary holding member 14
and also a radius dresser attachment 17 adapted to be held
by the rotary holding member 14.
Support member 13 is fastened to one end of base
member 12 by two pairs of screws 20, the heads of which are
shown in Figure 7. Support member 13 as well as base member 12
are fashioned from solid steel stock, and each of the screws
20 are fastened into a complementary threaded bore extending
longitudinally in the support member. Proximate to the bores
for screws 20 are a double row of four holes 21 as shown in
Figure 7. Each row of holes 21 comprises a first pair of holes
22 into each of which are pressed a dowel pin 23 (see Figure 1)
and an alternately-positioned second pair of holes 24 each of
which are threaded to receive a screw 25 (see Figure 1). A
pair of guide.bars 26 each have four holes bored therein, one
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pair of which are adapted to house the pair of dowel pins 23 and
the alternately-positioned pair of which are adapted for
placement of the pair of screws 25 therein. The four holes
in each guide bar 26 are in longitudinal-alignment and have
longitudinal spacing corresponding to that of the row of
holes 21. The double row of holes 21 and the pair of guide
bars 26 are precision machined and positioned on base member
12 prior to the attachment of base member 12 to support member
13. The mutual spacing of guide bars 26 and the width W of
support member 13 (see Figure 3) are such that support member
13 fits between guide bars 26 within a tolerance of 0.0002
inches. The four holes in base member 12 through which screws 20
are adapted to extend each have a diameter sufficiently larger than
the shaft diameter of the allen head cap screws 20 that their
exact positioning is not as critical as that of the two rows
of holes 21. As will be obvious, the holes in base member 12
through which screws 20 extend are counter-sunk so that the
heads of the screws do not protrude above the surface of
the base member.
As shown in Figures 2 and 3, support member 13 is
fashioned from solid steel stock having a circular bore generally`
designated as 28 extending centrally therethrough. The steel stock ,
is carborized and hardened to l/16-inch depth, then deep freeze
normalized (4 phase) for stability. Into each end of bore 28
is pressed a set of double row bearings 29. Between each
set of double row bearings 29 isa Meehanite annular spacer 30.
Meehanite is a very fine-grained cast iron, and the Meehanite spacer
absorbs any vibrations created by the bearings 29. A hollow spindle
shaft 31, having one end threaded and an integral collar 32 on its
other end, extends through the inner race of each of the set of
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bearings 29 so as to be rotatable relative to support member 13;
the outer diameter of shaft 31 is exactly 0.750 inches. Rotary
holding member 14 comprises a disc 33 and a connected block 34, as
shown in Figure 1, as well as shaft 31. Disc 33 is secured to
hollow spindle shaft 31 so as to extend in a plane parallel to
support member 13 and perpendicular to base member 12. That end
of hollow spindle shaft 31 which extends from the side of support
member 13 opposite to disc 33 is threaded, as shown in Figure 2,
the thread receiving an internally-threaded collar 35 which
lQ when in position prevents longitudinal movement of shaft 31
relative to support member 13. A set screw is threaded radially
into collar 35 to prevent relative movement between collar 35
and shaf~ 31. A handle 36, as shown in Figures 1, 2, and 3,
comprises a lever arm 37 having a larger end and a smaller
end. From the smaller end of arm 37 a post 38 extends normal
to the plane of arm 37. At the larger end of arm 37 and on
the opposite side from post 38 a collar 39 extends, the
inner diameter of collar 39 being slightly larger than the
diameter at the outer end of spindle shaft 31. A set screw
extends radially in collar 39 and secures handle 36 to the
outer end of spindle shaft 31.
Rotary holding member 14 comprises in part the disc 33,
which is fashioned from a solid piece of steel stock and which
has its symmetrical axis of rotation aligned with the axis
of rotation of spindle shaft 31. As shown in Figure 2, disc
33 has a radial dimension which is less than the distance
between the axis of rotation of spindle shaft 31 and the facing
surface of base member 12. Disc 33 has a diametrically-extending
groove 45, as more clearly shown in Figures 1 and 6. In cross
section, groove 45 is shaped such that each edge of the groove
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has a shoulder extending therealong. Rotary holding member 14
also comprises a clamping mechanism which is a generally rectan-
gular block 34 having a V-shaped groove in one end and a plate ~8
fastenable across that end of block 34. Four set screws 49
secure plate 48 to block 34. As shown in Figures 1 and 6,
the workpiece 50 is held against the inclined surfaces of
the V-shaped groove in block 34 by an insert 51 which acts
as a clamp when a pair of screws 52 are rotated to react
against plate 48. In case the workpiece to be installed in the
rotary holding member has a size greater than that between
block 34 and plate 48 a yoke clamp 55 is provided. Yoke clamp
55, as shown in Figure 1, has a pair of facing flanges 56
integrally formed on its legs, each of the flanges 56 entering
a respective groove 57 laterally positioned on rectangular
block 34. A screw 58 is rotatable in a threaded hole 59 in
yoke 55, screw 58 serving the same purpose as the screws in
plate 48, namely, to clamp the workpiece against the surfaces
of the V-shaped groove in rectangular block 34. It will, of
course, be necessary to remove plate 48 from rectangular block
34 when yoke 55 is being utilized.
Rectangular block 34 is secured in disc 33 by means
of a clamp 59A (shown in outline in Figure 2) which slides in
the broader portion of groove 45 and grabs against the shoulders
of that groove when a pair of screws 59B (shown in outline in - ,
Figure 2) positioned in holes 59C (see Figure 2) ln block 47
are rotated so as to more deeply penetrate a pair of threaded
holes in clamp 59A. The head of each of the screws sits on a
shoulder within the respective hold 59C, the body of each screw
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extending into a respective threaded hole in the clamp 59A.
Block 34 is movable along groove 45 when the screws 59B are
loosened.
Second support member 16 is slidable in a groove 60
that extends longitudinally in base member 12. A screw 61
extends through an elongated groove 62 in a base portion of
second support member 16 and threads into a selected one of a
longitudinal series of threaded holes 63 centred in the groove 62.
Second support member 16 comprises a block 65 which is adjustably
slidably connected to a base 66 by a slot and groove means. The
block 65 has a longitudinal series of threaded holes 67 adapted
to selectively house a screw 68. The combination of groove 62,
screw 61, and the series of holes 63 allow second support
member 16 to assume an infinite number of longitudinal positions
along base member 12. Since longitudinal groove 60 is laterally
centred in base member 12 and second support member 16 is
laterally symmetrical, second support member 16 is also laterally
centred in base member 12. In a similar manner, the combination
of the series of threaded holes 67 extending longitudinally in
block 65, screw 68 which is adapted to be selectively housed
therein, and the slot and groove means between block 65 and
base 66 allow the block 65 to assume an infinite number of
vertical positions relative to base 66. With screw 68 loosened,
block 65 can move relative to base 66 along a portion of
the length of the slot and groove means; if greater adjustment
is needed, screw 68 can be removed from the particular threaded
hole 67 and placed into an adjacent hole 67. Regarding the
slot and groove means between block 65 and base 66, base 66
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has a vertical ~roove ~not shown) form~d on lts on~ end face and
having a shape similar in cross section to that of groove 60;
block 65 has a longitudinal track with a complementary cross
section to that of the groove of base 66 on its one end face.
Extending through a longitudlnal bore in the upper
portion of block 65 is a pin 70 having a conical end portion
which is a 60 degree standard center. A screw 71 extends into
a threaded bore in the other end of pin 70, the head of screw
71 being retained in a groove 72 of a bracket 73 fastened by
screw 74 to block 65. As screw 71 is rotated, pin 70 is
retracted or extended from block 65.
As shown in Figures 1 and 2, base member 12 has a
series of longitudinally-extending grooves on that surface
adapted to rest upon the working surface of the grinding or
milling machine; those grooves comprise a pair of grooves 75
each positioned adjacent to a respective lateral edge of base
member 12 and three centrally-located grooves 76. The five
longitudinally-extending grooves are also shown in Figures 3 and
7. With reference to Figure 7, the circular shapes 77 represent
cylindrical cavities drilled in base member 12 to reduce the
overall weight of the holding tool of the subject invention. As
also shown in Figure 7, threaded bores 63 into which screw 61 is
selectively securable extend through the thickness of base
member 12 from the hollow of groove 60 to the hollow of the most
centrally-positioned groove 76. The grooves 75 and 76 and
the cylindrical cavities 77 improve the friction between that
surface of base member 12 and the grinding or milling machine
on which base member 12 rests. Base member 12 can be inter-
; changed with other base members of greater or lesser length,
depending on the requirements of the particular job.
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Rotary holding member 14 has groove 45 diametricallyextending on on~ planar surface and a circular groove 80
centred on the other planar surface. Circular groove 80 has
an inner periphery 81 and an outer periphery 82, inner
pe~iphery 81 having a lip extending therealong as ~hown in
Figure 2. A pair of stops 83 are adapted to slide in groove 80,
each stop 83 having a clamp connected thereto by a screw such
that the lip on the inner periphery of groove 80 may be clamped
between a stop 83 and its associated clamp to maintain the stop
83 at a fixed angular position on the disc 33. A pin 85 is
slidably mounted on a bracket 86 laterally extending from and
integral with support member 13, as shown in Figure 3. Pin 85
is slidable longitudinally on the rotary holding tool such that
its one end can be extended into groove 80; when in such
extended position, pin 85 allows only limited rotation of
. rotary holding member 14.
The circumference of the disc 33 is graduated
into 360 divisions, each division representing a degree of
relative angle of rotation between support member 13 and rotary
: 20 holding member 14. Secured to the outer end of support member
13 by four screws 88 is an indicator bracket 89 having, as
shown in Figure 1, an arcuate lip 90 extending as an arcuate
continuation of the circumference of disc 33 of rotary holding
member 14. Lip 90 is a graduated vernier allowing for accuracy
in relative angular displacement between support member 13 and
.: rotary holding member 14 of one-twelfth of one degree, i.e. 5
~ minutes. Each of the vernier markings on lip 90 is offset from
: the adjacent marking such that the spacing between the outermost
of the 12 equidistantly-spaced markings on the vernier correspond
.
. 30 to 35 degrees of rotation of the disc 33 If the central mark
on lip 90 and the 20 màrk, for instance, of the disc were first
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aligned and then the disc rot~ted slightly so that the first
adjacent mark on the lip 90 was opposite the 23 mark on the
disc, the angle of the disc would be 20 degrees plus 3/35
degrees. Set screw 91 acts as a spindle lock by acting against
spindle shaft 31 to prevent relative angular displacement
between rotary holding member 14 and support member 13.
Near the outer perimeter of the disc 33 are a
series of twenty-four longitudinally-extending bores 92 each
angularly displaced by 15, as shown in Figure 3. Longitudinally
slidable in support member 13 are a series of three pins 93,
the symmetrical axis of the pins lying in the same circular
arc as that extending through the symmetrical axis of the
bores 92. Pins 93 are angularly displaced from each other relative
to the centre of spindle shaft 31 by 20~. One end of each of
the pins 93 is machined into a generally triangular cross-
sectional shape so as to fit with close tolerance into any of
the bores 92. The shoulder formed by the transition of each
pin from circular to triangular cross section acts as a stop
limiting deeper penetration of the pin into a bore 92 of disc
33. The effect of the difference in relative angular
displacement between each adjacent pair of bores 92 and each
adjacent pair of pins 93 is to create a rapid, facile means
for angularly displacing rotary holding member 14 at 5
increments relative to support member 13. The 5 increments
result when pins 93 are sequentially inserted into rotary
holding member 14. With reference to Figure 3, the 5 increments
are obtained by repeatedly inserting in left to right order the
three pins 93, i.e. left, centre, right, left, centre, right,
left, etc. If the 5 increments are desired in movement of the
wheel in the opposite direction, right to left order of insertion
of the pins 93 is used, i.e. right, centre, left, right, centre,
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left, right, etc. The pins 93 are the series of bores 92
have together been previously referred to as releasable
angular locking means 15.
; Figure 6 illustrates the adaptability of the rotary
holding tool of the subject invention. Support member 13 and
rotary holding member 14 have been rotated such that a workpiece
50 positioned therein is rotated in the horizontal plane. A
pair of support brackets 95 have each been affixed to a
respective side of support member 13 by a pair of screws 96
placed into the threaded holes 97 of Figure 1. In the
configuration of Figure 6 pin 85 has been previously removed
from bracket 86 and handle 36 removed from the end of spindle
shaft 31. Rotary holding member 14 is rotated relative to
support member 13 by hand in this configuration, and releasable
~ angular locking means 15 as well as the vernier fine adjustment
; that utilizes arcuate lip 90 are both operable.
; Figure 8 is a side view of the rotary holding tool of
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the subject invention but illustrating a different rotary holding
member than that shown in Figure 2. The alternate rotary
:
holding member of Figure 8 is a three-piece "li~e centre"
- construction compriging an internally-threaded shaft 100 and
a hollow shaft 101, both shafts 100 and 101 having an outer
diameter sized such that they are insertable within the
cylindrical cavity of spindle shaft 31 and having an integral
lip on one of their ends such that a bolt 102 extending
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-~- through shaft 101 can be rotated into the threaded bore of
shaft 100; when bolt 102 is tightened, shaft 100 rotates with
handle 36. One end of shaft 100 is conical-shaped, and a
workpiece can be retained between that conical end portion
and the conical end portion of pin 70.
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The operation of the subject invention will next
be described. It should be obvious to a person skilled in the
art that the rotary holding tool of the subject invention has
the capability of producing all of the dies shown in Figure 9.
The base portion of each die is a portion of the steel stock
(of circular, square, hexagonal or other cross section) adapted
to be retained in block 34 of rotary holding member 14. The
other portion of each die in Figure 9 is formed by selectively
angularly-displacing the die while acting on the die with a
grinding or milling machine. A selected length is cut from the
steel stock and the selected material is placed against the
inclined surfaces of the V-shaped groove in block 34 of rotary
holding member 14. Screws 52 are tightened against an insert
(51 in Figure 1) which holds the selective workpiece 50 firmly
in block 34. As earlier described, if the workpiece is of
very large cross section plate 48 is removed from block 34 and
yoke 55 is applied to block 34 such that itsflanges 56 extend
,- into grooves 57. With yoke 55 in position the workpiece will
be held between the inclined surfaces of the V-shaped groove
in block 34 and an insert tnot shown) against which screw
' 58 acts.
Once the location of the axis of symmetry of the
portion of the workpiece to be machined has been determined,
` the screws in holes 59C are loosened and block 34 is slidably
displaced along groove 45 of disc 33. With reference to
Figure 9td) the axis of symmetry of the cylindrical stock
~' placed into block 34 is offset from the axis of symmetry o,f
n~ spindle shaft 31 by an amount "x", the screws in holes 58
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are then tightened. As will be obvious to a person skilled
in the art, the die with the eccentric offset of Figure 9(d)
will be formed when a grinding wheel is brought adjacent to
the retained stock and rotary holding member 14 i9 rotated.
Similarly, the die of Figure 9(b) i9 machined by displacing
the axis of symmetry of the stock by a distance "y" from
the axis of rotation of spindle shaft 31. In the case of the
die shown in Figure 9(b) the axis of symmetry of the stock
is, however, alternately displaced the distance "y" in both
, 10 directions along groove 45 from the axis of symmetry of spindle
shaft 31. The purpose of pin 85 and the pair of stops 83 should
now be obvious. Stops 83 can be adjusted such that rotary
holding member 14 is rotatable only through 180 so as to
place semi-cylindrical surfaces on the die of Figure 9(b).
, After the grinding of the two semi-cylindrical surfaces have
been completed the arcuate or straight surfaces connecting
; those semi-cylindrical surfaces can then easily be ground or
milled to shape.
It should be obvious that the dies of Figure 9(a),
(c), (e), (f), and (g) can be constructed with the axis of
`i~ symmetry of the stock positioned in-line with the axis of
; symmetry of spindle shaft 31. Utilizing releasable angular
- locking meansl5,5 increments in rotation of rotary holding
member 14 are possible and also multiples of 5 increments.
For instance, the die of Figure 9(a) is formed by utilizing
the same pin 93 positioned sequentially in four equi-angularly
; spaced bores 92. The die of Figure 3(c) would utilize the same
pin 93 positioned sequentially in six equi-angularly spaced
bores 92, while the dies of Figures 9(e), (f), and (g) would
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utilize 8, 3, and 12 equi-angularly spaced bores 92,
respectively.
When a die or other workpiece is being machined
~hich does not re~uire the axis of rotation of the workpiece
to be offset from the axis of rotation of spindle shaft 31,
block 34 or both block 34 and disc 33 may be removed from
the rotary holding tool; disc 33 is removed by loosening
the four screws holding it to the collar 32 of spindle shaft
31. With shafts 100 and 101 of the "live centre" positioned
in spindle shaft 31 the workpiece can be retained between the
conical end portion of shaft 100 and the conical end portion
of pin 70,as shown in Figure 8. Thisholding arrangement can
be very advantageous when the whole length of a workpiece
is to be machined and the presence of block 34 would present
a hindrance to such machining. Workpieces of diverse lengths
can be accommodated by varying the longitudinal position of
second support member 16 on base 12 and, if necessary, inter-
changing base 12 for a longer or shorter base.
,....
As shown in Figure 10, the rotary holding tool of
the subject invention is secured to the bed of a grinding
machine such that the workpiece held by the rotary holding
tool extends parallel to the axis of rotation of the grinding
wheel. The lowermost point on the grinding wheel is vertically
positioned slightly below the uppermost surface of the workpiece
such that grinding takes place when the axis of rotation of the
grinding wheel is horizontally offset from the axis of symmetry
of the workpiece by 0.030 inches. With the grinding wheel
maintained in that position, such that it is slightly horizontally
offset from being positioned directly above the workpiece,
the workpiece is slowly rotated and simultaneously the bed of
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the grinding machine moves the rotary holding tool and the
affixed workpiece normal to the plane of the grinding wheel.
Persons skilled in the art would be very familiar with
~ proper grinding techniques.
; Radius dresser attachment 17 was mentioned previously.
,i When its one end is fitted into the V-shaped groove of block 34,
~` it is used to dress grinding wheels, as shown in Figures 4 and 5.
Unlike the relative positioning of the grinding wheel and the
rotary holding tool in Figure 10, the rotary holding tool is
rotated such that its longitudinal axis is in the plane of the
,~!" grinding wheel. Radius dresser attachment 17 has a grinding
~' wheel cutter 105 positioned at its outer end and adapted to
be brought against the periphery of the grinding wheel as
shown in Figure 4. Stops 83 can be utilized to limit rotation
of rotary holding member 14 such that one or both edges of the
' grinding while are fully or partially rounded. Figure 5
'~ illustrates a grinding wheel on which one of the edges has
been fully rounded. The grinding wheel can subsequently be
~r placed adjacent to the workpiece 106 of Figure 5 so that the
rounded profile of the grinding wheel can be transferred to
the workpiece.
Although only a few uses of the rotary holding tool
of the subject inventionhave been described, a wide range
of other uses for the tool should be obvious to a skilled
machinist.
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