it is to be understood by one of ordinary skill in the art that the present discussion is a description of exemplary embodiments only , and is not intended as limiting the broader aspects of the present invention , which broader aspects are embodied in the exemplary construction . referring to fig1 and 2 , a chuck 10 in accordance with the present invention is illustrated . chuck 10 includes a front sleeve member 12 , an optional rear sleeve member 14 , a body member 16 and jaws 18 . body member 16 is generally cylindrical in shape and comprises a nose or forward section 20 and a tail or rearward section 22 . an axial bore 24 is formed in the nose section 20 of the body member 16 . axial bore 24 is somewhat larger than the largest tool shank that the chuck is designed to accommodate . a threaded bore 26 is formed in tail section 22 of body 16 and is of a standard size to mate with the drive shaft of a powered or hand driver ( not shown ). the bores 24 , 26 may communicate at the central region 28 of body member 16 . while a threaded bore 26 is illustrated , such bore could be replaced with a tapered bore of a standard size to mate with a tapered drive shaft . passageways 30 are formed in body member 16 to accommodate each jaw 18 . preferably , three jaws 18 are employed and each jaw 18 is separated from the adjacent jaw by an arc of approximately 120 degrees . the axes of the passageways 30 and the jaws 18 are angled with respect to the chuck axis but intersect the chuck axis at a common point ahead of the chuck body 16 . each jaw 18 has a tool engaging face 32 which is generally parallel to the axis of the chuck body 16 and threads 34 on its opposite or outer surface . threads 34 of any suitable type and pitch may be utilized within the scope of the present invention as would be readily apparent to one skilled in the art . as illustrated in fig1 and 2 , body member 16 includes a thrust ring member 36 which , in a preferred embodiment , is integral therewith . thrust ring member 36 includes a thrust face 38 . thrust face 38 includes an arcuate seating surface 40 for engagement with the inner race of a self - contained anti - friction bearing assembly 42 as will be described in more detail below . thrust ring member 36 includes a plurality of jaw guideways 30 formed around the circumference to permit retraction of the jaws 18 therethrough . body member 16 includes a rear cylindrical portion 44 with a knurled surface 46 thereon for receipt of optional rear sleeve 14 to be pressed thereon if so desired . body 16 further includes a first tapered portion 48 extending from rear cylindrical portion 44 to thrust ring 36 . a second tapered portion 50 extends from the area of thrust face 38 to a front cylindrical portion 52 . front cylindrical portion 52 is of greater diameter than the smaller end of second tapered portion 50 and forms a first circumferential groove 54 intermediate the nose and tail sections 20 and 22 of body 16 . body 16 further includes a reduced diameter nose portion 56 that is adapted to receive a nosepiece 58 as will be described in more detail below . the present invention further includes a nut 60 which , in a preferred embodiment , is a split nut and which includes threads 62 for mating with threads 34 on jaws 18 whereby when said nut is rotated with respect to said body , said jaws will be advanced or retracted . nut 60 is adapted to receive a retaining band 64 for maintaining nut 60 together after it is assembled . in the illustrated embodiment , a split nut is utilized because of the diameter of front cylindrical portion 52 . nut 60 includes drive slots 66 for mating with drive ribs 68 on front sleeve 12 so that when front sleeve 12 is rotated , nut 60 will rotate therewith and move jaws 18 as set forth above . a self - contained bearing assembly 42 is adapted to be placed between thrust ring 36 and a face 70 of nut 60 . self - contained bearing assembly 42 includes an inner race 72 , an outer race 74 and bearing elements 76 maintained therebetween . in a preferred embodiment , bearing elements 76 are ball bearings . self - contained bearing assembly 42 may further include a shroud 78 surrounding the inner and outer races 72 , 74 for maintaining the bearing assembly as a self - contained component . inner race 72 includes an arcuate surface that is dimensioned and configured to mate with arcuate seating surface 40 on thrust face 38 of thrust ring 36 . such mating relationship assists in alignment and minimization of both axial and radial stresses when the chuck is operated . in a preferred embodiment , self - contained bearing assembly 42 is a radial thrust bearing . use of a self - contained bearing assembly has a number of advantages . assembly is greatly simplified in that individual ball bearings and cages do not have to be handled . in addition , the body and nut are not required to be as hard or dense as is necessary with conventional bearing systems where the body or nut may also serve as a thrust race , thus allowing more flexibility in materials and reducing secondary manufacturing operations and , ultimately , cost . front sleeve member 12 is adapted to be loosely fitted over nose section 20 of chuck 10 . drive ribs 68 of front sleeve 12 engage drive slots 66 of nut 60 so that front sleeve 12 and nut 60 will be operatively connected , i . e ., when front sleeve 12 is rotated , nut 60 will rotate therewith . front sleeve 12 includes an annular ledge portion 79 adapted to rest at the inner face of front cylindrical portion 52 and nose portion 56 . nosepiece 58 is dimensioned and adapted to be pressed onto nose portion 56 to maintain front sleeve 12 on chuck 10 . it should be appreciated that nosepiece 58 could also be secured by snap fit , threading or the like . nosepiece 58 is exposed when said chuck is assembled and is preferably coated with a non - ferrous metallic coating to prevent rust and to enhance its appearance . in a preferred embodiment , such coating may be zinc or nickel , however , it should be appreciated that any suitable coating could be utilized . nosepiece 58 serves to maintain front sleeve member 12 in position on chuck 10 and in driving engagement with nut 60 . in addition , nosepiece 58 serves the dual purpose of providing an aesthetically pleasing cover for nose portion 56 that inhibits rust . this provides the advantage of an aesthetically pleasing appearance without the necessity to coat the entire body member 16 with a non - ferrous material . if desired , the rear sleeve member 14 may be omitted and the front sleeve member 12 extended to the tail end of body 16 . this alternative is feasible when a spindle lock or the like is provided on the driver or when the driver is used to tighten or loosen the jaws . the circumferential surface of the front sleeve member 12 may be knurled or may be provided with longitudinal ribs or other protrusions to enable the operator to grip it securely . in like manner , the circumferential surface of the rear sleeve member 14 , if employed , may be knurled or ribbed if desired . the front and rear sleeves may be fabricated from a structural plastic such as polycarbonate , a filled polypropylene , for example , glass filled polypropylene , or a blend of structural plastic materials . other composite materials such as , for example , graphite filled polymerics would also be suitable in certain environments . as will be appreciated by one skilled in the art , the materials from which the chuck of the present invention is fabricated will depend on the end use of the chuck , and the above are provided by way of example only . it will be appreciated that rear sleeve member 14 is fixed to body member 16 while front sleeve member 12 is operatively associated with nut 60 and secured to body member 16 for relative rotation therewith . relative movement of the front and rear sleeve members , 12 and 14 , due to the interaction between threads 34 on jaws 18 and threads 62 on nut 60 causes jaws 18 to be advanced or retracted , depending upon the direction of relative movement . referring to fig3 and 4 , a chuck 110 in accordance with another embodiment of the present invention is illustrated . chuck 110 includes a front sleeve member 112 , an optional rear sleeve member 114 , a body member 116 and jaws 118 . body member 116 is generally cylindrical in shape and comprises a nose or forward section 120 and a tail or rearward section 122 . an axial bore 124 is formed in the nose section 120 of the body member 116 . axial bore 124 is somewhat larger than the largest tool shank that the chuck is designed to accommodate . a threaded bore 126 is formed in tail section 122 of body 116 and is of a standard size to mate with the drive shaft of a powered or hand driver ( not shown ). the bores 124 , 126 may communicate at the central region 128 of body member 116 . while a threaded bore 126 is illustrated , such bore could be replaced with a tapered bore of a standard size to mate with a tapered drive shaft . passageways 130 are formed in body member 116 to accommodate each jaw 118 . preferably , three jaws 118 are employed and each jaw 118 is separated from the adjacent jaw by an arc of approximately 120 degrees . the axes of the passageways 130 and the jaws 118 are angled with respect to the chuck axis but intersect the chuck axis at a common point ahead of the chuck body 116 . each jaw 118 has a tool engaging face 132 which is generally parallel to the axis of the chuck body 116 and threads 134 on its opposite or outer surface . threads 134 of any suitable type and pitch may be utilized within the scope of the present invention as would be readily apparent to one skilled in the art . as illustrated in fig3 and 4 , body member 116 includes a thrust ring member 136 which , in a preferred embodiment , is integral therewith . thrust ring member 136 includes a plurality of jaw guideways 150 formed around the circumference to permit retraction of the jaws 118 therethrough . thrust ring member 136 may have an arcuate seating surface for receipt of a self - contained bearing assembly as described in the above embodiment . body member 116 includes a rear cylindrical portion 144 with a knurled surface 146 thereon for receipt of optional rear sleeve 114 to be pressed thereon if so desired . the present invention further includes a nut 160 which , in a preferred embodiment , is a unitary nut and which includes threads 162 for mating with threads 134 on jaws 118 whereby when said nut is rotated with respect to said body , said jaws will be advanced or retracted . as illustrated in fig4 nut 160 includes drive slots 166 for mating with drive ribs 168 on front sleeve 112 so that when front sleeve 112 is rotated , nut 160 will rotate therewith and move jaws 118 as set forth above . a self - contained bearing assembly 142 is adapted to be placed between thrust ring 136 and a face 170 of nut 160 . self - contained bearing assembly 142 includes an inner race 172 , an outer race 174 and bearing elements 176 maintained therebetween . in a preferred embodiment , bearing elements 176 are ball bearings . self - contained bearing assembly 142 may further include a shroud 178 surrounding the inner and outer races 172 , 174 for maintaining the bearing assembly as a self - contained component . inner race 172 may include an arcuate surface that is dimensioned and configured to mate with an arcuate seating surface on the thrust face of thrust ring 136 such as illustrated in the previous embodiment , if so desired . such mating relationship assists in alignment and minimization of both axial and radial friction when the chuck is operated . in a preferred embodiment , self - contained bearing assembly 142 is a radial thrust bearing . it should be appreciated that any type bearing arrangement including plain bearing surfaces could be utilized in the present invention . referring again to fig3 and 4 , a nut retainer member is generally illustrated at 143 . nut retainer member 143 includes a first generally cylindrical portion 145 and a second frusto - conical portion 147 . substantially cylindrical portion 145 is configured to be press fitted over nose or forward section 120 in a location so that a portion 149 will engage nut 160 to prevent nut 160 from moving axially forward more than a desired amount . this desired amount can be determined by the location in which the nut retainer member is pressed onto the body member . it should be appreciated that the nut retainer member 143 is adapted to be press fitted onto the nose portion of the body , but could be secured in any other suitable manner in accordance with the present invention . nut member 160 defines a ledge 151 and nut retainer member 143 , through its portion 149 , is adapted to be received on ledge 151 when contact is made between nut 160 and nut retainer member 143 . front sleeve member 112 is adapted to be loosely fitted over nose section 120 of chuck 110 . drive ribs 168 of front sleeve 112 engage drive slots 166 of nut 160 so that front sleeve 112 and nut 160 will be operatively rotationally connected , i . e ., when front sleeve 112 is rotated , nut 160 will rotate therewith . a nosepiece 158 is dimensioned and adapted to be pressed onto the front of the forward section 120 of body member 116 to maintain front sleeve 112 on chuck 110 . it should be appreciated that nosepiece 158 could also be secured by snap fit , threading or the like . nosepiece 158 is exposed when the chuck is assembled and is preferably coated with a non - ferrous metallic coating to prevent rust and to enhance its appearance . in a preferred embodiment , such coating may be zinc or nickel , however , it should be appreciated that any suitable coating could be utilized . nosepiece 158 serves to maintain front sleeve member 112 in position on chuck 110 and in driving engagement with nut 160 . in addition , nosepiece 158 serves the dual purpose of providing an aesthetically pleasing cover for nose portion 156 that inhibits rust . this provides the advantage of an aesthetically pleasing appearance without the necessity to coat the entire body member 116 with a non - ferrous material . if desired , the rear sleeve member 114 may be omitted and the front sleeve member 112 extended to the tail end of body 116 . this alternative is feasible when a spindle lock or the like is provided on the driver or when the driver is used to tighten or loosen the jaws . it should also be appreciated that a snap ring or any other mechanism could be utilized to maintain front sleeve 112 in place in lieu of nosepiece 158 . the circumferential surface of the front sleeve member 112 may be knurled or may be provided with longitudinal ribs or other protrusions to enable the operator to grip it securely . in like manner , the circumferential surface of the rear sleeve member 114 , if employed , may be knurled or ribbed if desired . the front and rear sleeves may be fabricated from a structural plastic such as polycarbonate , a filled polypropylene , for example , glass filled polypropylene , or a blend of structural plastic materials . other composite materials such as , for example , graphite filled polymerics would also be suitable in certain environments . as will be appreciated by one skilled in the art , the materials from which the chuck of the present invention is fabricated will depend on the end use of the chuck , and the above are provided by way of example only . it will be appreciated that rear sleeve member 114 is fixed to body member 116 while front sleeve member 112 is operatively associated with nut 160 and secured to body member 116 for relative rotation therewith . relative movement of the front and rear sleeve members , 112 and 114 , due to the interaction between threads 134 on jaws 118 and threads 162 on nut 160 causes jaws 118 to be advanced or retracted , depending upon the direction of relative movement . while the above description is set forth with respect to a keyless chuck , it should be appreciated that the principles of the present invention may be equally applicable to a keyed chuck , and such is within the scope of the present invention . these and other modifications and variations to the present invention may be practiced by those of ordinary skill in the art , without departing from the spirit and scope of the present invention , which is more particularly set forth in the appended claims . in addition , it should be understood that aspects of the various embodiments may be interchanged both in whole or in part . furthermore , those of ordinary skill in the art will appreciate that the foregoing description is by way of example only , and is not intended to be limitative of the invention so further described in such appended claims .