Chuck for rotary metal cutting tool

A chuck for a cylindrical rotary metal cutting tool, such as an end mill, is provided with a liquid coolant system. The chuck is constructed to direct cooling liquid onto a cutting tool secured in an axial bore defined therein with a plurality of converging liquid streams directed at the tool. The chuck is constructed with alternative passageways. Liquid coolant may be directed along a central, axial cooling liquid passageway remote from a transverse end face of the chuck. Liquid may pass radially outwardly therefrom through radial bores and into intersecting longitudinal cooling liquid distribution ducts which are inclined toward the axis of the tool holder and which terminate in outlet ports in the end face. The radial bores are plugged at locations radially outwardly from the intersection of the ducts with the radial bores. Alternatively, liquid coolant may be carried through an annular manifold and directed radially inwardly into a plurality of arcuate, concave liquid distribution troughs located on the outer surface of the tool holder, and radially inwardly through the radial bores. Interior plugs within the tool holder force the liquid coolant into the inclined ducts. A removable end plate with diverting apertures may be fastened to the end face of the tool holder to divert liquid coolant onto a cutting tool with streams of liquid impinging thereon at selected angles.

1. Field of the Invention 
The present invention relates to an improved, versatile, liquid cooled 
chuck for rotary, metal cutting tools, such as end mills. 
2. Description of the Prior Art 
There are numerous metal machining operations which employ cylindrical bits 
rotated at high speed to cut metal chips from a workpiece. Exemplary among 
such devices are end mills, shell mills, drills, routers, reams, bores, 
and other high speed, rotary systems which cut metal with a sharp bit. 
Various liquid coolant systems have been devised in attempts to prevent 
mill and drill bits from becoming dull rapidly. In conventional practice 
the bit of a drill or milling machine is cooled by merely spraying water 
from a distance onto the rotating bit of the milling machine or drill. 
However, in actuality very little cooling water reaches the tip of the bit 
and most of the water is thrown from the bit by centrifugal force or drops 
from the bit due to the force of gravity. As a result, the milling machine 
or drill bit will typically overheat and become dull. Furthermore, chips 
of material which are cut from the metal stock tend to cling to a mill or 
drill bit, thereby increasing the heat generated. This reduces the quality 
of milling and also dulls the bit more rapidly. 
One prior, improved chuck for a rotary cutting tool is described in my 
prior U.S. patent application Ser. No. 773,028, filed Sept. 6, 1985, now 
U.S. Pat. No. 4,669,933 issued June 2, 1987. However, the chuck described 
in my prior application has one disadvantage in that an annular groove 
must extend around the entire circumference of the tool holder. This 
annular groove is necessary to provide a channel of continuous 
communication from a stationary collar, located concentrically about the 
tool holder at the channel, and internal ducts within the tool holder 
which are inclined toward the axis of the tool. The existence of such an 
annular channel in the outer surface of the tool holder creates a certain 
amount of weakness in the tool holder. Moreover, my prior system requires 
an annular, cooling liquid distribution collar within which the tool 
holder must rotate in sliding engagement with the collar. In such systems 
a considerable amount of leakage of cooling liquid can develop at the 
interface between the tool holder and the collar within which the tool 
holder rotates. This leakage reduces the amount of cooling liquid which 
ultimately reaches the cutting tool. Moreover, many machine shops do not 
employ annular cooling liquid manifolds, but instead provide cooling 
liquid supply systems which are adapted to supply cooling liquid into a 
central, axial cooling liquid passageway defined within the spindle of the 
tool holder. Thus, while the improved chuck of my prior invention may be 
advantageously employed in supplying cooling liquid to rotary cutting 
tools in certain installations, it lacks versatility for use in other 
machine shop cutting tool coolant systems. 
SUMMARY OF THE INVENTION 
The present invention is an improved chuck for a cylindrical rotary tool 
for cutting away metal. The chuck of my new invention is comprised of a 
cylindrical, annular rotatable tool holder having a transverse end face in 
which an axial bore is defined to receive a cylindrical tool. A plurality 
of radial liquid distribution bores are defined in the tool holder and are 
tapped or otherwise equipped with some form of fastener to receive plugs 
therein. A plurality of arcuate, transverse concave grooves are defined in 
the outer surface of the tool holder. One groove is defined in the outer 
surface of the tool holder at each radial bore. The grooves are located 
remote from the end face at which the cooling liquid ultimately emanates. 
The grooves thereby define a plurality of discontinuous, arcuate cooling 
liquid distribution troughs. A plurality of cooling liquid distribution 
ducts are defined in the tool holder so as to intersect the radial liquid 
distribution bores proximate to the liquid distribution troughs. 
Preferably, the ducts are defined at an inclination toward the axis of the 
tool holder to terminate in outlet ports in the end face. The outlet ports 
are located closer to the axis of the tool holder than are the 
intersections of the cooling liquid distribution ducts with the radial 
liquid distribution bores. 
In a preferred embodiment of the invention the tool holder includes a 
central, axial cooling liquid passageway remote from the transverse end 
face of the tool holder. The axial passageway intersects the radial liquid 
distribution bores. The radial bores are internally threaded at 
intersections with the liquid distribution troughs. The radial bores are 
also internally threaded between their intersections with the liquid 
distribution ducts and their intersections with the central axial 
passageway. Thus, plugs may be threadably engaged in the radial bores to 
define two, altenative paths of cooling liquid supply. 
If the cooling liquid supply coupling arrangement is adapted to supply 
cooling liquid through the spindle of the tool holder to the central, 
axial cooling liquid passageway, the plugs are threadably engaged in the 
radial bores between the intersections of the bores with the arcuate, 
liquid distribution troughs and their intersections with the liquid 
distribution ducts. Cooling liquid then travels along the central, axial 
liquid passageway and is directed radially outwardly through the radial 
bores to the plugs. The plugs prevent the liquid from leaving the tool 
holder at the liquid distribution troughs. The plugs instead force the 
liquid through the liquid distribution ducts, where it emerges from the 
outlet ports at the end face in streams directed onto the tool bit. 
Alternatively, the plugs may be engaged in the radial bores at locations 
between the intersections of the radial bores with the liquid distribution 
ducts and the intersections of the radial bores with the central, axial 
cooling liquid passageway. When the plugs are disposed in this fashion the 
system is provided with an annular cooling liquid distribution collar 
having a cooling liquid inlet and positioned about the tool holder in 
sliding contact therewith and in communication with the cooling liquid 
distribution troughs. The tool holder rotates within the collar. Cooling 
liquid, under pressure travels along a cooling liquid path from the 
cooling liquid inlet to the collar, through the annular collar, and into 
the distribution troughs. From the cooling liquid distribution troughs the 
liquid travels radially inwardly into the radial bores and is deflected by 
the plugs into the liquid distribution ducts. The liquid then likewise 
emerges from the end face of the tool holder through the outlet ports in 
streams directed onto the tool bit. 
In one embodiment of the invention the liquid distribution ducts are 
oriented at an inclination toward the axis of the tool holder from their 
intersections with the radial liquid distribution bores. With this duct 
configuration the outlet ports are located closer to the axis of the tool 
holder than are the intersections of the cooling liquid distribution ducts 
with the radial liquid distribution bores. The resultant effect is to 
supply cooling liquid in jets which converge upon the cutting tool held in 
the holder. 
In an alternative embodiment of the invention the liquid coolant ducts in 
the tool holder need not be inclined toward the axis of the tool holder, 
but rather are parallel to the tool holder axis. In this alternative 
embodiment the tool holder may be equipped with an end plate which is 
removably attached across the end face of the tool holder. The end plate 
has a central opening coaxial with the axial bore in the tool holder, and 
separate radially displaced liquid passageway openings are aligned with 
each of the outlet ports. While the longitudinal ducts through the tool 
holder are not inclined toward the tool holder axis, the passageway 
openings in the end plate are so inclined. Thus, in this embodiment, as in 
the embodiment where the ducts in the tool holder are inclined toward the 
tool holder axis, cooling liquid is ejected as a plurality of jets which 
converge on the cutting tool. 
In yet another alternative embodiment nozzles are provided at the outlet 
ports in place of the end plate. The nozzles are secured in the outlet 
ports and deflect cooling liquid from the liquid distribution ducts onto 
the tool bit at an angle of inclination thereto. 
The chuck of the invention is comprised of a cylindrical, annular rotatable 
tool holder having a transverse end face in which an axial bore is defined 
to receive the shank of a cylindrical cutting tool. Where the cutting tool 
is an end mill, some means, such as one or more set screws are provided 
for securing the tool shank in the tool holder so that it turns in 
rotation with the tool holder. The tool shank typically has a flat side 
against which the set screws bear. 
The invention may also be applied to a shell mill holder. In a shell mill 
holder, a cylindrical annular sleeve is centered on the transverse end 
face and projects axially therefrom. The internal wall of the sleeve is 
tapped to receive a threaded draw bolt which serves as a releasable 
fastener for immobilizing the tool to rotate with the tool holder. Axially 
projecting keys are also defined on the transverse end face and extend 
radially outwardly from the internal sleeve. These keys fit into 
corresponding slots on the shell mill. The keys and slots cooperate to 
lock the shell mill so that is rotates with the shell mill holder. The 
draw bolt fits into an axial counterbore in the shell mill and extends 
through an axial bore in the shell mill to engage the threads of the 
internal wall of the sleeve. The remaining structure of the shell mill 
holder corresponds to that of an end mill holder, as described in the 
preceeding paragraph. 
A tool holder constructed according to the invention has a very significant 
advantage over the conventional practice of spraying water onto a rotating 
metal cutting tool. The liquid distribution ducts, when considered as 
projected onto a plane containing the holder axis, are inclined at an 
acute angle so that the water emerging from the outlet ports is directed 
toward the cutting tool with both radial and longitudinal components of 
force. The longitudinal component of force tends to carry the water to the 
remote, free end of the cutting tool, while the radial component of force 
acts in opposition to the centrifugal force tending to fling the water 
away from the cutting tool. A cooling effect is needed most at the remote 
free end of the cutting tool before the centrifugal force imparted to the 
water by the rotating cutting tool flings the water free from the rotating 
tool. 
The angle at which the ducts are preferably formed in the tool holder 
relative to the tool holder axis, when considered in a plane containing 
the tool holder axis, is ideally the maximum acute angle which will 
overcome the centrifugal force imparted to the water but still allow the 
coolant to reach the tip of the cutting tool. The greater the rotary speed 
of the tool holder, the greater the desired incline of the liquid 
distribution ducts inward towardly the tool holder axis. That is, the 
ducts should be more steeply inclined relative to the tool holder axis for 
a high rotary speed in order to overcome the greater, opposing centrifugal 
force tending to throw the water clear from the cutting tool. 
The preferred angle of the inclination of the ducts relative to the tool 
holder axis will also increase with the diameter of the metal cutting bit. 
The desired angle will decrease with increasing liquid pressure and flow 
rate. Typically the ducts are each inclined toward the holder axis at an 
acute angle between about two degrees and about thirty degrees, when 
considered as projected onto a plane containing the duct and the tool 
holder axis. Also, when the flutes of the tool bit are helical, the ducts 
are preferably oriented somewhere between longitudinal alignment with the 
tool bit and an angle in alignment with the helical angle of the flutes, 
when considered in planes oriented perpendicular to radial lines from the 
tool holder axis. 
The improved chuck of the invention may be used with machine tools that are 
rotated about either a vertical or a horizontal axis. The chuck of the 
invention is used most advantageously with a roughing type end mill where 
intense heat is created, and with tools which are rotated about horizontal 
axes. 
The improved chuck of the invention is extremely versatile and may be 
utilized with liquid coolant supply systems in which liquid coolant is 
supplied either axially to a central, axial cooling liquid passageway 
through the spindle of the tool holder, or radially inwardly from an 
annular hollow, coolant manifold disposed about the holder and within 
which the tool holder rotates. 
The use of a removable end plate provides the improved chuck of the 
invention with further versatility. The end plate is preferably bolted 
onto the end face of the tool holder and held in liquid tight, sealing 
engagement therewith. Interchangable end plates may be utilized for 
different metal cutting tools. The liquid passageway openings in the end 
plate selected for a particular tool will deflect the flowing cooling 
liquid to the angle relative to the tool and tool holder axis which is 
most appropriate for the metal cutting tool mounted in the axial bore of 
the tool holder. For example, the flutes of some milling tools, such as 
some end mills, are straight and extend parallel to the axis of the tool. 
An end plate in which the axes of the passageway openings intersect the 
tool holder axis is most appropriate for such end mills. 
Most end mills have flutes that are oriented in a helical spiral about the 
axis of the end mill bit, however. It may be desirable for the liquid 
passageway openings in the interchangeable end plate employed to be 
aligned to follow the helical orientation of the end mill flutes. For 
example, the liquid passageway openings may be oriented at an angle of 
about three and one half degrees from a line perpendicular to the end face 
of the tool holder, as measured in a plane parallel to the tool holder 
axis and perpendicular to a radial line emanating therefrom. This 
inclination is in addition to any inclination which the liquid passageway 
openings may have toward the tool holder axis as measured in planes 
intersecting the liquid passageway openings and containing the tool holder 
axis. The inclination of the liquid passageway openings as measured in 
planes perpendicular to the tool holder end face and to radial lines 
emanating from the tool holder axis and parallel to the tool holder axis 
may be as much as twenty seven and one half degrees or even thirty degrees 
to accommodate some shell mills. 
The invention may be described with greater clarity and particularity by 
reference to the accompanying drawings.

FIGS. 1-3 illustrate two embodiments of an improved end mill chuck 
according to the invention which employ the same tool holder. Both of 
these embodiments are comprised of a cylindrical annular tool holder 10, 
depicted in FIG. 1, having a transverse end face 12 with an axial bore 14 
defined therein perpendicular to the end face 12. The bore 14 is adapted 
to receive the shank of a solid, cylindrical end mill or other metal 
cutting tool. A plurality of radial liquid distribution bores 16 are 
defined in the tool holder 10 and are adapted to engageably receive plugs 
therein, such as the plugs 18 depicted in FIGS. 2 and 3. A plurality of 
transverse arcuate, discontinuous concave liquid distribution troughs 20 
are defined in the outer surface of the tool holder 10 remote from the end 
face 12. The troughs 20 are formed in a plane perpendicular to the axial 
bore 14 centered over each of the radial liquid distribution bores 16. 
Separate liquid distribution ducts 22 are formed within the tool holder 10 
to intersect each of the liquid distribution bores 16 at intersections 
indicated at 24 in FIGS. 1 and 3. The ducts 22 terminate at outlet ports 
26 which are defined in the end face 12 proximate to the axial bore 14 
therein. In the tool holder 10 the outlet ports 26 are closer to the axis 
of the axial bore 14 than are the intersections 24 of the liquid 
distribution ducts 22 with the liquid distribution bores 16. 
Four different radial liquid distribution bores 16 oriented 90 degrees 
apart, are defined in the tool holder 10, as depicted in FIG. 2. All of 
the bores 16 are internally tapped throughout to receive plugs 18 which 
are threadably engaged therein. The plugs 18 may be engaged in liquid 
tight sealing arrangement anywhere along the bores 16 from adjacent the 
arcuate troughs 20, as depicted in FIG. 2, or interiorly from the 
interfaces 24 as depicted in FIG. 3. 
The arcuate troughs 20 do not form an annular channel in the outer surface 
28 of the tool holder 10, but to the contrary are formed as a plurality of 
separated, transverse, concave grooves, defined discontinuously in the 
outer surface 28 of the tool holder 10. A separate liquid distribution 
trough 20 is centered over each of the radial bores 16 and extends over an 
arc of preferably between about 45 and 65 degrees. The cooling liquid 
distribution troughs 20 are formed as separated discontinuous, arcuate 
grooves rather than as an annular continuous channel so as to avoid 
unnecessarily weakening the structure of the tool holder 10. 
The radial liquid distribution bores 16 intersect the axial passageway 30 
at intersections 34. As previously noted, the radial bores 16 are tapped 
throughout their lengths and are therefore internally threaded both at 
their intersections 34 with the passageway 30 and at their intersections 
36 with the liquid distribution troughs 20 formed by the segmental grooves 
in the outer surface 28 of the tool holder 10. While the bores 16 which 
are depicted are threaded their entire lengths for ease of machining, it 
is important only that they are threaded at some location between their 
intersections with the troughs 20 and the ducts 22 and at some location 
interiorally of the ducts 22 between the ducts 22 and the intersections 34 
with the axial passageway 30. 
As illustrated in FIG. 2, the plugs 18 may be threadably engaged with the 
radial bores 16 between the intersections 24 and 36 of the radial bores 16 
with the liquid distribution ducts 22 and the troughs 20, respectively. 
The plugs 18 may be engaged at the intersections 36 of the bores 16 with 
the liquid distribution troughs 20. When the plugs 18 are positioned in 
the manner depicted in FIG. 2, a cooling liquid path of travel is defined 
along the central, axial cooling liquid passageway 30, radially outwardly 
past the intersections 34, through the radial bores 16 to the plugs 18, 
and through the liquid distribution ducts 22 to emerge from the end face 
12 at the outlet ports 26. With the plugs 18 positioned as depicted in 
FIG. 2, cooling liquid is supplied from a coupling at the spindle 38 of 
the tool holder 10. Since the cooling liquid distribution ducts 22 are 
defined in the tool holder 10 to intersect the radial distribution bores 
16 at the intersections 24 proximate to the liquid distribution troughs 20 
and are oriented at an inclination toward the axis of the tool holder 10, 
the outlet ports 26 in the end face 12 are located closer to the axis of 
the tool holder 10 than are the intersections 24 of the cooling liquid 
distribution ducts 22 with the radial liquid distribution bores 16. With 
the plug arrangement of FIG. 2, cooling liquid supplied through a coupling 
at the tool holder spindle 38 is directed in converging fashion toward the 
tool holder axis from the outlet ports 26. 
The angle of inclination of the liquid distribution ducts 22 relative to 
the axis of the tool holder 10 when measured in a plane containing the 
tool holder axis is preferably between about three degrees and fifteen 
degrees and may, for example, be seven and one half degrees. Cooling 
liquid emanating from the outlet ports 26 arrives with a longitudinal 
component of force toward the cantilevered tip of the cutting tool held in 
the axial bore 14 and with a radially inwardly directed component of 
force. The streams of water emanating from the outlet ports 26 thereby 
resist the centrifugal force imparted by the rotating cutting tool bit 
which tends to cast the water outwardly away from the bit. The water 
thereby remains in contact with the bit along its entire length, and is 
thus able to perform the intended function of cooling the bit to prevent 
it from becoming dull quickly. Also by remaining in contact with the metal 
cutting bit longer, the water is also able to flush chips of metal away 
from the tip of the bit. This improves the ability of a machinist to 
control the chips and enables the end bit, or any other cutting bit, to 
take a greater depth of cut. 
The improved metal cutting tool chuck of the invention may also be utilized 
with systems which employ an annular cooling liquid distribution collar 
40, of the type depicted in FIG. 3. The cooling liquid distribution collar 
40 depicted at FIG. 3 has a cooling liquid inlet 42. The liquid 
distribution collar 40 remains stationary while the tool holder 10 rotates 
therewithin in sliding contact therewith. Annular snap rings 44 are 
located in shallow, annular grooves in the outer surface 28 of the tool 
holder 10 so as to straddle the liquid distribution collar 40. The snap 
rings 44 prevent the liquid distribution collar 40 from shifting 
longitudinally on the outer surface 28 of the tool holder 10. The annular 
liquid distribution channel defined within the collar 40 is in 
communication with the liquid distribution troughs 20. 
The plugs 18 may be threadably engaged in the bores 16 and then advanced 
all the way into the radial bores 16 to their intersections 34 thereof 
with the axial passageway 30, as depicted in FIG. 3. With the plugs 18 
engaged as illustrated in FIG. 3, a cooling liquid path of travel is 
defined from the cooling liquid inlet 42, through the annular collar 40 
and into the liquid distribution troughs 20. The cooling liquid passes 
radially inwardly into the radial bores 16 and through the liquid 
distribution ducts 22 to emerge from the end face 12. As with the 
arrangement of FIG. 2, the cooling water emanating from the outlet ports 
26 is directed longitudinally toward the cantilevered end of a bit held 
within the axial bore 14, as well as toward the tool holder axis. Because 
the plugs 18 are interposed between the axial cooling liquid passageway 30 
and the liquid distribution ducts 22, liquid supplied from the annular 
collar 40 is isolated from the axial passageway 30 and is thereby forced 
through the liquid distribution ducts 22. 
It can be seen that by selectively positioning the plugs 18 either between 
the intersections 24 of the liquid cooling ducts 22 with the radial bores 
16 and the intersections 36 of the radial bores 16 with the liquid 
distribution troughs 20, as depicted in FIG. 2, or alternatively between 
the intersections 34 of the radial bores 16 with the axial passageway 30, 
and the intersections 24 of the bores 16 with the liquid distribution 
ducts 22, alternative cooling liquid paths of travel are defined. With the 
plugs 18 engaged in the radial bores 16 between the troughs 20 and the 
liquid distribution ducts 22, as depicted in FIG. 2, a liquid path of 
fluid flow is defined from the axial passageway 30, through the radial 
ducts 16, and into the liquid distribution ducts 22. Alternatively, when 
the plugs 18 are engaged in the radial bores 16 between the intersections 
24 of the ducts 22 with the radial bores 16 and the intersections 34 of 
the bores 16 with the axial passageway 30, a path of coolant flow is 
defined radially inwardly from the annular collar 40, through the troughs 
20, into the radial ducts 16, and along the liquid distribution ducts 22. 
FIGS. 4, 5 and 6 illustrate an alternative embodiment of the improved tool 
chuck of the invention. The tool holder 10' depicted in FIGS. 4 and 5, is 
similar in many respects to the tool holder 10, and the component 
structural elements which find equivalent structure in the tool holder 10 
are indicated by primed reference numbers corresponding thereto in FIGS. 4 
and 5. 
The tool holder 10' differs from the tool holder 10 in that the liquid 
distribution ducts 22' are not inclined toward the axis of the tool holder 
10', but rather extend parallel to the axis of the tool holder 10'. The 
end face 12' of the tool holder 10' is not exposed, but to the contrary 
one of several interchangable disk-shaped end plates 46 is removably 
secured in contact therewith by means of machine screws 48 which extend 
into the structure of the tool holder 10' parallel to the tool holder 
axis, as depicted in FIG. 5. The end plate 46 is a generally annular, 
disk-shaped structure and has a central, circular axial opening 50 defined 
therethrough. The opening 50 is of a diameter equal to the diameter of the 
bore 14' in the tool holder 10'. 
The end plate 46 is removably secured to the transverse end face 12' and 
has apertures defined therein. The apertures form separate liquid 
passageway openings 52 which are radially displaced from the central 
opening 50. At the interface surface 54 of the end plate 46 the liquid 
passageway openings 52 are aligned with each of the outlet ports 26' and 
are inclined therefrom toward the axis of the tool holder 10', as 
illustrated in FIG. 4. The liquid passageway openings 52 are thereby 
oriented to receive flowing liquid from the liquid distribution ducts 22' 
and to divert that liquid flow toward the axis of the axial bore 14'. In 
the embodiment of FIGS. 4, 5 and 6 each of the axes of the liquid 
passageway openings 52 lies in a plane containing the axis of the tool 
holder 10'. 
With some cutting tools it may be desirable for the liquid passageway 
openings of an end plate to be aligned so as to divert liquid flow 
therefrom in jets which do not intersect the axes of the axial bore 14'. 
To the contrary, it may be desirable for the axis of the liquid passageway 
openings to extend in a skew orientation relative to the axis of rotation 
of the tool holder 10'. 
FIG. 6 is a sectional detail of one of the axial passageways 52 of the end 
plate 46 taken in a plane containing the liquid passageway opening axis 
and intersecting the axis of rotation of the tool holder 10'. FIG. 7, on 
the other hand, is a comparable detail of a single liquid passageway 
opening 52' of an alternative, interchangable end plate 46'. The end plate 
46' may be fastened to the end face 12' of the tool holder 10' in place of 
the end plate 46 by means of the machine bolts 48 in the manner depicted 
in FIG. 5. Unlike the liquid passageway openings 52, however, the liquid 
passageway openings 52' are also inclined laterally such that the axis of 
the liquid passageway openings 52' do not lie in planes containing the 
axis of rotation of the tool holder 10' and a liquid distribution duct 
22'. The orientation of the passageway 52' is laterally inclined at an 
angle of about 31/2 degrees in the direction of a helical angle of a flute 
of a metal cutting tool which is held in the axial bore 14'. 
FIG. 8 is a detail of another single liquid passageway opening 52" in 
another alternatively interchangable end plate 46". The lateral angle of 
inclination of the axis of the liquid passageway opening 52" is even 
greater than that of the liquid passageway opening 52', and may, for 
example, be 271/2 degrees. The end plate 46" might, for example, be 
utilized with an end mill, where there is a very substantial angle of 
helical orientation of the milling flutes. 
The apertures 52' of the end plate 46' as well as the apertures 52" of the 
end plate 46" are congruent with the outlet ports 26' of the tool holder 
10' where the interface surface 54 of the end plate resides in contact 
with the end face 12'. However, the apertures 52' and 52" are aligned to 
divert liquid flow therefrom in jets which do not intersect the axis of 
the axial bore 14'. To the contrary, the axes of the apertures 52' and 52" 
are inclined to predetermined degrees as illustrated in FIGS. 7 and 8, 
considered in planes oriented perpendicular to radial lines from the tool 
holder axis. 
FIG. 9 illustrates another modification of the embodiment of either FIG. 2 
or FIG. 3 which employs an arrangement for directing the flow of cooling 
water from the water distribution ducts 22 at an angle toward the axis of 
the axial bore 14. In the modification of FIG. 9 adjustably positionable 
nozzles 58 are positioned in the outlet ports 26 of the liquid 
distribution ducts 22 instead of employing an end plate having liquid 
passageway openings of fixed orientation. The adjustable nozzles 58 can be 
seated in the outlet ports 22 at the end face 12 of a tool holder 10 and 
oriented to deflect liquid coolant from the liquid distribution ducts 22 
at any desired angle relative to the end face 12 of the tool holder 10. 
The nozzle bodies 60 of the nozzles 58 are tubular an extend into the 
liquid distribution ducts 22 a short distance. The bodies 60 house 
deflecting spheres 62 which have channels therethrough. The deflecting 
spheres 62 can be oriented within the nozzle bodies 60 as desired to 
achieve a desired angle of coolant deflection. 
Undoubtedly, numerous variations and modifications of the invention will 
become readily apparent to those familiar with metal cutting machining 
operations. For example, if a tool holder will not be operated with liquid 
supplied through an annular collar of the type depicted in FIG. 3, the 
tool holder can be strengthened by eliminating the arcuate troughs 20, so 
that the radial bores intersect the outer cylindrical surface of the tool 
holder in circular interface openings. The elimination of the troughs 20 
will strengthen the structure of the tool holder. Alternatively, if the 
tool holder does not have a central, axial liquid coolant passageway, it 
can be strengthened if the radial bores 16 are blind bores and extend into 
the structure of the tool holder only a short distance sufficient to 
intersect the liquid distribution ducts 22 or 22'. Also, it should be 
understood that interchangable end plates can be used with tool holders 
where the cooling liquid distribution ducts are either parallel to the 
tool holder axis, as in FIG. 4, or inclined thereto as in FIGS. 1 and 3. 
Other modifications are also possible For example, the bores 16 need not be 
radial but can be merely transverse to the axis of the tool holder 10. 
Plugs can be engaged in such transverse bores by fastening means other 
than threads. Accordingly, the scope of the invention should not be 
construed as limited to the specific embodiments of the improved rotary 
tool chuck depicted and described herein, but rather is defined in the 
claims appended hereto.