Abstract:
A variable depth router and base assembly can include a ring-type, depth-adjustment mechanism. The base assembly can be a two-piece base wherein one piece is disposed inside the other. One of the pieces can include an annular lip or recess that can cooperate with levers on the adjustment ring to secure the router to the base assembly. The two-piece base assembly can facilitate the manufacture of the base assembly, can allow the use of different materials for different portions of the base assembly, and can provide a more economical base assembly. The use of differing materials can facilitate the using of more wear-resistant materials where needed while avoiding the costs of such materials in locations where it is not needed. The two-piece base assembly may allow various features to be economically incorporated into one of the pieces, thereby facilitating the manufacturing and assembly of the base assembly.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application No. 60/943,486, filed on Jun. 12, 2007. The disclosure of the above application is incorporated herein by reference. 
    
    
     FIELD 
     The present disclosure relates to routers and, more particularly, to a base assembly that can be used with a router to provide a variable depth. 
     BACKGROUND 
     The statements in this section merely provide background information related to the present teachings and may not constitute prior art. 
     Various types of power tools comprise a cutting tool or bit that is raised or lowered relative to a base that rests on or against the workpiece. Often the tool or bit is attached to the output shaft of a motor unit that can be vertically or axially moved relative to the base. Movement of the motor unit and attached tool bit relative to the base unit determines the depth of cut into the workpiece. 
     Routers, including some laminate trimmers, are constructed according to this basic design. The router bit is attached to the motor output spindle by means of a tool holder such as a collet or chuck and the bit projects through an opening in the base to contact the workpiece. The motor unit is mounted to the base by means that allow the operator to move the motor and bit axially relative to the base in order to determine the depth of cut of the bit. Router base and depth of cut systems fall into two commonly recognized categories. They are plunge-base routers and fixed-base routers (including so-called D-handle bases). Generally speaking, plunge routers comprise a generally planar base element, a motor unit, and a plurality of support columns on which the motor unit is vertically movably mounted above the base. Usually, the motor unit is biased upward or away from the base. Means are provided for finely adjusting the depth of cut and for locking the motor unit at the selected depth/height against the biasing force. 
     Fixed-base routers usually comprise a generally cylindrical base and a motor unit with a cylindrical housing portion. The cylindrical portion of the motor housing fits snugly but movably within an annulus of the cylindrical portion of the base with the motor spindle and router bit projecting downward beyond the lowest portion of the base. The cylindrical portion of the base often includes a longitudinal or axial cut or gap that permits the base diameter to expand or contract slightly under the force of a clamp mechanism that bridges the gap and that can be used to tighten the base onto the motor housing within. Means for adjusting the depth of cut by adjusting the vertical or axial position of the motor unit and bit within the base are also provided. The base clamp is loosened for adjusting the cutting depth and after the desired depth is set with the depth adjusting means the base clamp is tightened to lock the motor housing at the set position. 
     The typical base is made from a one-piece casting. The use of a one-piece casting requires that multiple surfaces be machined to accommodate the various components and features, such as the adjustment ring and the motor housing. Additionally, the multiple machined surfaces are required to allow precise positioning of the power tool relative to the base. The machining of multiple surfaces can be time-consuming, require intricate tooling, and/or increase the overall cost of the base. Thus, it would be advantageous to provide a base requiring less machined surfaces. Additionally, the use of a single, one-piece casting results in a base of a single material. In order to provide the desired strength for the base, the thickness of the base may be required to be large. This large size may make handling of the base and the tool awkward and/or inconvenient. Additionally, in the typical base, the anti-rotation feature is a separate component that is attached to the base. The use of a separate anti-rotation feature is an additional assembly step, can require an additional machining operation, and is an additional cost in the production of the base. Thus, it may be advantageous to provide a base requiring less machining operations and also which may be more convenient to use. Additionally, it would be advantageous if the cost of producing the base could be reduced. 
     SUMMARY 
     A router according to the present teachings can include a ring-type, depth-adjustment mechanism. The depth-adjustment mechanism can include an adjustment ring. The adjustment ring can include levers coupled thereto that can be used to secure the router to a fixed-base assembly. The base assembly can be a two-piece base assembly wherein one piece is disposed inside the other. One of the pieces can include an annular lip or recess that can cooperate with the lever on the adjustment ring to secure the router to the base assembly. The use of two separate pieces to form the base assembly can facilitate manufacture of the base assembly and attachment of the router thereto. The two-piece base assembly can also allow the use of a smaller diameter adjustment ring to increase user comfort. Additionally, the use of a two-piece base assembly can enable different materials to be utilized for different portions of the base assembly, thereby providing a more economical base assembly and facilitating the use of more wear-resistant materials where needed. Moreover, the use of a two-piece base assembly may allow various features to be economically incorporated into one of the pieces, thereby facilitating the manufacturing and assembly of the base assembly. 
     A portable router base assembly according to the present teachings includes a housing and a retaining ring. The housing has a foot, an upper portion, and an interior defined at least in part by an interior surface. The upper portion includes an upper surface. The housing interior is configured to receive a portion of a portable router. The interior surface includes a radially outwardly extending annular recess adjacent the upper surface. The retaining ring includes an interior, a generally cylindrical portion, and a top surface. The top surface at least partially defines an opening to the retaining ring interior. The cylindrical portion can be at least partially disposed in the annular recess of the housing. The retaining ring interior is configured to receive the portion of the portable router through the opening. 
     According to another aspect of the present teachings, a power tool assembly includes a portable router and a fixed-base assembly. The portable router includes a head portion, a generally cylindrical portion, a motor unit, and a spindle operable to receive a working tool. The fixed-base assembly is operable to receive the portable router and support the portable router in a desired axial position relative to a working surface. The fixed-base assembly includes a housing and a retaining ring. The housing has a foot, an upper portion, and an interior defined at least in part by an interior surface. The upper portion includes an upper surface. The housing interior receives the cylindrical portion of the portable router. The interior surface includes a radially outwardly extending annular recess adjacent the upper surface. The retaining ring includes an interior, a generally cylindrical portion, and a top surface. The top surface at least partially defines an opening to the retaining ring interior. The retaining ring cylindrical portion is at least partially disposed in the annular recess of the housing. The retaining ring interior is configured to receive the cylindrical portion of the portable router through the opening. 
     Further areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. 
    
    
     
       DRAWINGS 
       The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present teachings in any way. 
         FIG. 1  is an exploded view of a router disengaged from a fixed-base assembly according to the present teachings; 
         FIG. 2  is an exploded view of the fixed-base assembly according to the present teachings; 
         FIG. 3  is a perspective view of the fixed-base assembly according to the present teachings; 
         FIG. 4  is a fragmented cross-sectional view of the fixed-base assembly of  FIG. 3  along line  4 - 4  with the depth-indicator ring removed; 
         FIG. 5  is a fragmented cross-sectional view similar to the view of  FIG. 4  of a conventional fixed base configured to accommodate the router of  FIG. 1 ; 
         FIG. 6  is a fragmented cross-sectional view of the fixed-base assembly of  FIG. 4  with a depth-adjustment ring and the associated lever coupled thereto disposed on the fixed-base assembly according to the present teachings; 
         FIG. 7  is a fragmented cross-sectional view of the conventional fixed base of  FIG. 5  with a depth-adjustment ring and the associated lever coupled thereto disposed on the conventional fixed base; 
         FIG. 8  is a plan view of the fixed-base assembly according to the present teachings with the depth-adjustment ring coupled thereto; 
         FIG. 9  is a plan view similar to the view of  FIG. 8  of a conventional fixed base with the depth-adjustment ring coupled thereto; 
         FIG. 10  is a fragmented cross-sectional view similar to that shown in  FIG. 4  of an alternate embodiment of the fixed-base assembly according to the present teachings; 
         FIG. 11  is a fragmented cross-sectional view similar to that shown in  FIG. 4  of another alternate embodiment of the fixed-base assembly according to the present teachings; 
         FIG. 12  is a fragmented cross-sectional view similar to that shown in  FIG. 4  of still another alternate embodiment of the fixed-base assembly according to the present teachings; 
         FIG. 13  is a fragmented perspective view of yet another alternate embodiment of a fixed-base assembly according to the present teachings; and 
         FIG. 14  is a cross-sectional view of the fixed-base assembly of  FIG. 13  along line  14 - 14 . 
     
    
    
     DETAILED DESCRIPTION 
     The following description is merely exemplary in nature and is not intended to limit the present teachings, application, or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features (e.g.,  20 ,  120 ,  220 , etc.). 
     The present teachings provide an improved base assembly that can be used with a power tool having a depth-adjustment mechanism and which can be quickly coupled and de-coupled thereto for use with other implements. While shown throughout the drawings in a fixed-base router, those skilled in the art will appreciate that the present teachings are not so limited in scope. In this regard, the present teachings will be understood to be readily adaptable for use in other tools incorporating motor housings axially moveable in a base assembly by means of a rotatable ring element threadably engaged with the motor housing. 
     Referring now to  FIG. 1 , a first embodiment of a power tool  20  according to the present teachings is shown. Power tool  20  is illustrated in the form of a router and can include a motor unit  22 , a fixed-base assembly  24 , and a depth-of-cut adjustment ring  26 . 
     Motor unit  22  can include an electric motor (not shown) within a housing comprising a head portion  30  and a cylindrical portion  32 . The motor can be powered through a cord  33  and controlled by a switch  34 . In some embodiments, the motor may be powered by a battery pack. A motor spindle  36  can project from the bottom of motor unit  22 . A collet  38  can be attached to the end of spindle  36 . Collet  38  can hold cutting tools, such as router bits, which can then rotate with rotation of spindle  36 . Cylindrical portion  32  can include threads  40  that engage with complementary threads  41  ( FIG. 6 ) on adjustment ring  26 . Cylindrical portion  32  can also include an exterior and axially extending slot  42  that can engage with projecting features  44  ( FIGS. 4 and 6 ) in the interior of housing  50  to prevent rotation between motor unit  22  and base assembly  24 . Projecting features  44 , as known in the art, can each include a head portion  46  and a stem portion  48  and can extend through a pair of openings  49  in housing  50 . Openings  49  can be machined in housing  50  and projecting features  44  can be subsequently inserted therein. Head portions  46  project radially inwardly into the interior of housing  50  and engage with slot  42  to prevent relative rotation between motor unit  22  and base assembly  24 . Projecting features  44  can be retained in openings  49  in a variety of manners. By way of non-limiting example, projecting features  44  can be press fit into openings  49  or can include a knurled surface that can engage with openings  49  to retain projecting features  44  therein. 
     Referring now to  FIGS. 1-4 , base assembly  24  can include a generally axially extending cylindrical housing  50  with a flared foot  52  that forms a flat planar surface for travel along a workpiece. Housing  50  can include a large aperture  53  therein that allows visibility of the cutting tool coupled to collet  38 . A section  51  of an upper portion  54  of housing  50  can include an axial gap  55  and a horizontal slot  57  that permits expansion and contraction of section  51  of upper portion  54  under the influence of a clamp assembly  56 , which can be constructed and can operate in a well-known manner. Upper portion  54  can form a generally cylindrical interior surface  58  which can be sized to accommodate cylindrical portion  32  of motor unit  22  such that when clamp assembly  56  is opened/released motor unit  22  may slide easily within base assembly  24 , and when clamp assembly  56  is closed/engaged can hold cylindrical portion  32  of motor unit  22  firmly and non-slideably therein. Housing  50  can be made from a variety of materials, as known in the art. By way of non-limiting example, housing  50  can be diecast aluminum and diecast magnesium. 
     Interior surface  58  of upper portion  54  can include an annular radially outwardly extending recess  60  that can be machined therein and dimensioned to receive a retaining ring  62 . Recess  60  can be above section  51  and can be dimensioned to allow retaining ring  62  to be press fit into housing  50  for retention therein. Retaining ring  62  can be a formed component, and can include a top surface or edge  74 , a first generally cylindrical portion  64 , and an annular radially outwardly extending lip  66  above cylindrical portion  64 . The inner diameter of retaining ring  62  can be dimensioned to allow cylindrical portion  32  of motor unit  22  to move relatively freely therein. With this configuration, retaining ring  62  does not constrain movement of motor unit  22  regardless of the position of clamp assembly  56 . Rather, the constraining of motor unit  22  is performed by housing  50  and clamp assembly  56 . 
     A depth-indicator ring  68  can be disposed on a top surface  70  of housing  50  and be retained thereon by lip  66  of retaining ring  62 . Top surface  70  may be an as formed surface or a machined surface. In the preferred embodiment, top surface  70  provides a support for depth-indicator ring  68  and does not need to be a machined surface. In other embodiments, top surface  70  may be utilized to provide a precise support for adjustment ring  26 . When this is the case, top surface  70  can be a machined surface to thereby ensure the top surface  70  is parallel with the flat planar bottom surface of foot  52 . This machining operation of top surface  70  can allow precise positioning of router  20  and control of the depth of the cut. In the embodiment shown in  FIGS. 1-4 ,  6 , and  8 , top surface  74  of retaining ring  62  provides vertical support for motor unit  22  via adjustment ring  26 . Specifically, as shown in  FIG. 6 , adjustment ring  26  rests on top surface  74  which thereby provides vertical support for adjustment ring  26  which in turn supplies vertical support for motor unit  22 . When this is the case, top surface  74  may be precisely positioned relative to housing  50  to ensure that top surface  74  is parallel with the flat planar bottom surface of foot  52 . This can be achieved by proper dimensioning of recess  60  and of retaining ring  62 . 
     Retaining ring  62  can be a formed component that can be easily manufactured and can be made from a variety of materials. By way of non-limiting example, retaining ring  62  can be hardened steel and stainless steel. Retaining ring  62  can be made by a variety of processes. By way of non-limiting example, retaining ring  62  can be stamped, deep-drawn, or made in a metal spinning process. Additionally, retaining ring  62  can be formed with steel prior to the steel being hardened. 
     Recess  60  in interior surface  58  of housing  50  can be easily formed therein through a simple machining operation. Recess  60  and top surface  70  (when machined) may be formed in a single machining operation. Upper portion  54  and retaining ring  62  facilitate the selective attachment of motor unit  22  to base assembly  24 , as described below. The features to selectively retain motor unit  22  to base assembly  24  can be easily and economically produced by machining a single surface of the interior surface  58  of housing  50  to form recess  60 , and optionally top surface  70 , and through the simple forming of retaining ring  62 . Housing  50  and retaining ring  62  can be different materials and these different materials can provide advantages over the typical fixed base construction as described below. 
     Referring now to  FIG. 6 , adjustment ring  26  is shown coupled to base assembly  24  without motor unit  22  upon which adjustment ring  26  is normally disposed. Adjustment ring  26  is supported by top surface  74  and can include a pair of levers  76  (only one shown) that are pivotally coupled to an exterior of adjustment ring  26 . Levers  76  can be equally spaced about the periphery of adjustment ring  26 . Lever  76  can include a retaining tang  78  on one end thereof that extends radially inwardly relative to adjustment ring  26 . Lever  76  can be biased by a spring (not shown) so that tang  78  is in its radially innermost position and can engage with the underside of lip  66 , as shown in  FIG. 6 , to retain motor unit  22  to base assembly  24 . Pushing radially inwardly on upper end  80  of lever  76  causes lever  76  to pivot about pivot  82  and tang  78  to move radially outwardly so that lever  76  disengages with lip  66  of retaining ring  62  and motor unit  22  (along with adjustment ring  26 ) can be removed from base assembly  24 . When lever  76  is in its biased position, tang  78  engages with lip  66  of retaining ring  62  to prevent removal of motor unit  22  (along with adjustment ring  26 ) from base assembly  24 . 
     Adjustment ring  26  includes threads  41  that engage with threads  40  on cylindrical portion  32  of motor unit  22 . The engagement between threads  41  of adjustment ring  26  and threads  40  of motor unit  22  allows motor unit  22  to be moved axially relative to base assembly  24  by relative rotation therebetween so that the depth of the cutting tool attached to collet  38  can be adjusted. Specifically, adjustment ring  26  can be rotated relative to housing  50  while motor unit  22  remains rotationally stationary relative to housing  50  due to the interaction of slot  42  with projecting features  44 . Levers  76  do not prevent the rotation of adjustment ring  26  relative to housing  50 . In this manner, adjustment ring  26  can be rotated to adjust the depth of cut without requiring a user to engage or disengage levers  76 . When a desired cutting depth has been achieved, clamp assembly  56  of housing  50  can be closed/engaged to thereby secure motor unit  22  to housing  50 . When motor unit  22  is secured to housing  50 , rotation of adjustment ring  26  is inhibited due to the interaction of threads  40  of motor unit  22  and threads  41  of adjustment ring  26 . 
     Thus, in router  20  according to the present teachings motor unit  22  can be easily removed from and secured to base assembly  24 . Clamp assembly  56  of base assembly  24  can be opened/disengaged and motor unit  22  can be axially positioned within the interior of base assembly  24 . The position of adjustment ring  26  on cylindrical portion  32  determines the axial position of motor unit  22  on base assembly  24 . Levers  76  on adjustment ring  26  can automatically engage with lip  66  with the complementary sloping surfaces  83 ,  84  of tangs  78  and lip  66 , respectively, causing levers  76  to pivot about pivot  82  as tangs  78  slip over lip  66  and automatically secure motor unit  22  to base assembly  24 . Adjustment ring  26  can be rotated relative to base assembly  24  to position motor unit  22  in a desired axial position. When in the desired axial position, clamp assembly  56  can be closed/engaged to thereby secure motor unit  22  within housing  50  with interior surface  58  of upper portion  54  diminishing its diameter and securing itself to cylindrical portion  32  of motor unit  22 . Router  20  can then be operated as a fixed-base router. 
     To remove router  20  from base assembly  24 , clamp assembly  56  can be opened/disengaged and upper ends  80  of levers  76  depressed radially inwardly so that tangs  78  extends radially outwardly beyond lip  66 . Motor unit  22  (along with adjustment ring  26 ) can then be lifted axially relative to base assembly  24  and removed therefrom. Router  20  can then be used with other attachment features, such as a plunge base (not shown). 
     The base assembly  24  according to the present teachings may be more easily and economically produced versus a conventional base. For example, as shown in  FIGS. 5 and 7 , a conventional housing  86 , in addition to the machining required to form the flat planar bottom surface, can require the machining of multiple surfaces to provide the same function as retaining ring  62  and housing  50 . In particular, housing  86  can require the machining of a top surface  87  along with a first exterior annular recess  88  and chamfer  89  to allow the tangs of the levers to engage therewith. Additionally, a second annular recess  90  and chamfer  91  may be required to be machined therein to hold a depth-indicator ring  92 . These additional machined surfaces of a conventional housing  86  can increase the cost of the tooling and the time to machine housing  86  over that of base assembly  24 . Additionally, these multiple machined surfaces may require multiple setups, thereby further increasing the time required to produce a conventional housing  86 . This is in direct contrast with the base assembly  24  according to the present teachings which may have a single machined recess  60  (excluding the machined flat planar bottom surface which is common to both housing  50  and housing  86 ) which may be machined with a single tooling and setup. Additionally, the tooling required to provide recess  60  is of a simple design and does not require complex or intricate cutting details. Even in the event that top surface  70  is also a machined surface, top surface  70  can be machined simultaneously with recess  60  and can still utilize a single tooling and setup. Additionally, the tooling that will be used to simultaneously machine both top surface  70  and recess  60  would still be of a simple design and would not require complex or intricate cutting details. Thus, the base assembly  24  according to the present teachings may be more easily and economically produced versus a conventional base. 
     The base assembly  24  according to the present teachings may allow for a smaller base assembly and/or adjustment ring versus a conventional base. The smaller size can advantageously facilitate handling and control of router  20  and may provide a more pleasing experience for the user. Specifically, as shown in  FIG. 5 , the portion of housing  86  within which first annular recess  88  is machined must have a sufficient thickness/width to adequately retain motor unit  22  to housing  86 . Depending upon the strength and machinability constraints of the material of which housing  86  is formed, the required thickness of the housing at first annular recess  88  can vary. In contrast, as can be seen when comparing  FIG. 4  to  FIG. 5 , a base assembly  24  according to the present teachings can use two different materials for housing  50  and retaining ring  62 . As a result, retaining ring  62  can be chosen from a material that allows for a much smaller thickness/width than would be required if machining the retaining ring recess within housing  50 . That is, as shown in  FIG. 4 , the width W 1  of retaining ring  62  can be substantially smaller than the width W 2  of a base having a conventional housing  86 . Width W 1  of retaining ring  62  can also be less than the width W 3  of upper portion  54  of housing  50 . The reduced width W 1  of retaining ring  62  can allow the use of an adjustment ring  26  having a smaller outer diameter. For example, as shown in  FIGS. 8 and 9 , adjustment ring  26  used with a base assembly  24  according to the present teachings can have an outer diameter OD 1  that is substantially less than the outer diameter OD 2  of an adjustment ring  94  on a conventional base with housing  86 . The reduced outer diameter OD 1  of adjustment ring  26  can aid user comfort and allow a user to more easily grip adjustment ring  26  during rotation to adjust the axial position of motor unit  22  relative to base assembly  24 . Thus, base assembly  24  according to the present teachings may allow for a smaller base assembly and/or adjustment ring versus a conventional base. 
     An additional advantage of a base assembly  24  according to the present teachings is the ability to use differing materials having differing properties for housing  50  and retaining ring  62 . For example, retaining ring  62  can be made from a more durable material while housing  50  can be made from a less durable material. The use of a more durable material for retaining ring  62  may allow for the reduced width W 1  discussed above relative to a conventional base with housing  86 . Additionally, the use of a more durable material may provide a better tactile sensation or feel when using router  20  throughout its lifespan. For example, if a conventional base housing  86  is dropped or damaged, the top surface  87  may become marred, deformed, or dented. As a result, when a user is rotating the adjustment ring  94  along top surface  87 , these bumps or deformations may provide a non-pleasing tactile sensation. Additionally, these deformations may also affect the axial movement of motor unit  22  relative to housing  86  such that the same precision in adjustment may not be achieved. In contrast, the use of a more durable material for retaining ring  62  may allow base assembly  24  to continue to provide a pleasing tactile sensation and precise control of the axial position when subjected to the same types of potentially damage-causing incidents. Thus, a base assembly  24  according to the present teachings in using different materials having differing properties for housing  50  and retaining ring  62  may provide a more durable base assembly  24  which can increase the longevity of base assembly  24  and/or provide a more enjoyable tactile experience by a user. 
     Yet another advantage of a base assembly  24  according to the present teachings using differing materials is that the cost may be reduced. For example, differing materials having differing costs can be used for housing  50  and retaining ring  62 . For example, retaining ring  62  may be made from a first material having a first cost while housing  50  is made from a second material having a second cost. The second material may be less expensive than that which would be required to form a housing  86  of a conventional base. Because the differing parts of base assembly  24  may provide differing functions, different material requirements are necessary for retaining ring  62  and housing  50 . As a result, it may be possible to select more economical materials for housing  50  than is available when selecting material for housing  86  of a conventional base. Thus, the use of different materials may allow for a more economical selection of materials over a conventional base by allowing different materials for housing  50  and retaining ring  62 . 
     Referring now to  FIG. 10 , an alternate embodiment of the fixed-base assembly  124  according to the present teachings is shown. Base assembly  124  is similar to base assembly  24  discussed above. As such, only the main differences are described herein. Base assembly  124  advantageously incorporates an anti-rotation feature into retaining ring  162 . In particular, a radially inwardly extending projecting feature  144  is integral with retaining ring  162 . Projecting feature  144  extends axially along retaining ring  162  and is dimensioned to be received in slot  42  of motor unit  22 . Projecting feature  144  can be easily formed in retaining ring  162  during the forming thereof. By way of non-limiting example, projecting feature  144  can be formed in retaining ring  162  during a stamping, deep-drawing, or metal-spinning process. It should be appreciated that in some embodiments projecting feature  144  can be formed in retaining ring  162  subsequent to the forming of retaining ring  162 . The forming of projecting feature  144  integral with retaining ring  162  eliminates the need for separate components that are utilized to provide the anti-rotation feature, as discussed above with reference to base assembly  24  and as utilized in conventional fixed-base housings. The forming of projecting feature  144  as an integral feature of retaining ring  162  also eliminates the need to machine openings  49  through housing  150 . Thus, the use of a projecting feature  144  that is integral with retaining ring  162  can advantageously eliminate a separate machining operation for housing  150 , can eliminate the need for separate and distinct anti-rotation features, and can be economically formed during the forming of retaining ring  162 . 
     Base assembly  124  may also include axial retaining features  172  that inhibit removing of retaining ring  162  from housing  150 . In particular, axial retaining features  172  can include a plurality of tabs in retaining ring  162  that extend radially outwardly as they extend axially upwardly. Axial retaining features  172  can be spaced apart along retaining ring  162 . Recess  160  can include a shoulder  161  that extends radially inwardly. Recess  160  is axially dimensioned such that shoulder  161  engages with axial retaining features  172  and axially retains retaining ring  162  in housing  150 . Engagement between axial retaining features  172  and shoulder  161  inhibit removal of retaining ring  162  from housing  150 . Axial retaining features  172  can be used in conjunction with press fitting of retaining ring  162  into housing  150 . In some embodiments, it may be possible to utilize axial retaining features  172  as the sole means of axially retaining retaining ring  162  in housing  150 . The use of axial retaining features  172  can facilitate the precise positioning of router  20  on base assembly  124  versus that of press fitting the retaining ring. Specifically, the manufacturing tolerances of forming recess  160  and the axial length of retaining ring  162  and axial retaining features  172  are more easily met than when also trying to meet the tolerances required for press fitting the retaining ring into the housing. 
     Axial retaining features  172  can be easily manufactured during the forming of retaining ring  162 . By way of non-limiting example, axial retaining features  172  can be formed during a stamping, deep-drawing, or metal-spinning process when forming retaining ring  162 . It should be appreciated that in some embodiments axial retaining features  172  can be formed in retaining ring  162  subsequent to the forming of retaining ring  162 . Thus, a base assembly  124  according to the present teachings can advantageously include axial retaining features to facilitate retaining of retaining ring  162  and housing  150 . 
     Base assembly  124  may include a second lip  173  on retaining ring  162 . Second lip  173  is below first lip  166  and can be used to retain a depth-indicator ring  68  thereon. In particular, the depth-indicator ring  68  can be positioned between top surface  170  of housing  150  and second lip  173  of retaining ring  162 . The use of second lip  173  can prevent/inhibit inadvertent removal of a depth-indicator ring  68  from base assembly  124 . 
     Referring now to  FIG. 11 , another alternate embodiment of a fixed-base assembly  224  according to the present teachings is shown. Base assembly  224  is similar to base assembly  124  discussed above. As such, only the main differences therebetween are described herein. Base assembly  224  can include a retaining ring  262  with a top surface  274  that facilitates the insertion of motor unit  22  therein. Specifically, top surface  274  can be rounded and can be formed by the juncture of sloping surface  284  and an inner wall  275  of retaining ring  262 . Inner wall  275  extends axially along the inner surface of retaining ring  262  between top surface  274  and the inner surface of second lip  273 . Sloping surface  284 , top surface  274 , and inner wall  275  may provide a continuous surface that is rounded on the top thereof and can taper slightly radially inwardly. As a result, the opening to retaining ring  262  can facilitate the insertion of cylindrical portion  32  of motor unit  22  therein. Thus, a base assembly  224  according to the present teachings can advantageously incorporate features in retaining ring  262  that facilitate the insertion of motor unit  22  therein. Additionally, the use of rounded top surface  274  avoids any abrupt edges or features that may inhibit the insertion of cylindrical portion  32  of motor unit  22  into base assembly  224 . 
     Referring now to  FIG. 12 , another alternate embodiment of a fixed-base assembly  324  according to the present teachings is shown. Base assembly  324  is similar to fixed-base assembly  24  and  124  discussed above. As such, only the main differences are described herein. Base assembly  324  utilizes a different axial retaining feature  372 . In this embodiment, axial retaining feature  372  is a radially outwardly extending projection that circumscribes the periphery of retaining ring  362 . In this configuration, axial retaining feature  372  is easily formed in retaining ring  362  during the forming thereof. By way of non-limiting example, axial retaining feature  372  can be formed during a stamping, deep-drawing, or metal-spinning process when forming retaining ring  362 . To accommodate axial retaining feature  372 , recess  360  includes an annular groove  361  that extends radially outwardly within recess  360 . Groove  361  is complementary to axial retaining feature  372 . 
     Retaining ring  362  is positioned in the interior of housing  350  through the top and axial retaining feature  372  snaps into groove  361  in recess  360 . The engagement of axial retaining feature  372  in groove  361  inhibits removal of retaining ring  362  from housing  350 . 
     Groove  361  can be easily formed in housing  350  during the forming of recess  360 . In particular, the tooling utilized to form recess  360  can include an additional feature that also forms groove  361  when machining recess  360 . 
     While axial retaining feature  372  is shown and described as being a continuous axial retaining feature  372  that circumscribes the periphery of retaining ring  362 , it should be appreciated that axial retaining feature  372  can be comprised of a plurality of discrete segments that are spaced apart along the periphery and engaged with groove  361 . 
     Thus, a base assembly  324  according to the present teachings can utilize an annular groove  361  and a radially outwardly projecting axial retaining feature  372  to secure retaining ring  362  and housing  350 . The use of axial retaining feature  372  and groove  361  can be easily constructed in retaining ring  362  and housing  350 . 
     Referring now to  FIGS. 13 and 14 , a fixed-base assembly  424  according to still another embodiment of the present teachings is shown. Base assembly  424  is similar to base assembly  24  discussed above. As such, only the main differences are described herein. Base assembly  424  incorporates a different type of clamping assembly to secure router  20  within base assembly  424 . Specifically, base assembly  424  includes a clamping assembly  493  that eliminates the need for gap  55  and slot  57  in upper portion  454 . Clamping assembly  493  includes a clamp spring  495 , a pivot pin  497 , a clamp lever  498 , and, optionally, a clamp pad  499 . Clamp lever  498  has a cammed surface and is engaged with one end  495   a  of clamp spring  495 , while clamp pad  499  is associated with the other end  495   b  of clamp spring  495 . Clamp pad  499  extends through an opening  451  in upper portion  454  of housing  450 . 
     Clamp pad  499  can move radially inwardly and outwardly with the movement of clamp lever  498  through clamp spring  495 . This movement allows clamping assembly  493  to secure router  20  in base assembly  424 . Specifically, clamp lever  498  can be rotated about a pivot  485  between open and closed positions. When in the closed position, clamp lever  498  is adjacent housing  450  and causes end  495   a  of spring  495  to move radially outwardly which in turn causes end  495   b  to move radially inwardly as clamp spring  495  pivots about pivot pin  497 . When this is the case, clamp pad  499  exerts a clamping force Fc (as shown in phantom in  FIG. 14 ) which clamps router  20  in a fixed position relative to base assembly  424 . When clamp lever  498  is rotated away from housing  450 , as shown in  FIGS. 13 and 14 , end  495   a  moves radially inwardly, allowing end  495   b  to move radially outwardly such that clamp pad  499  no longer exerts force Fc against router  20 . Router  20  can then removed from base assembly  424  or have its axial position adjusted relative thereto through the adjustment ring. 
     Thus, in base assembly  424 , a clamping assembly  493  is utilized to selectively secure router  20  in base assembly  424 . Clamping assembly  493  can be easily operated by moving clamp lever  498  about pivot  485  between the engaged and disengaged positions. 
     While the present teachings have been shown and explained with reference to specific illustrations, it should be appreciated that variations and deviations to the illustrations shown can be employed without departing from the spirit and scope of the present teachings. For example, it should be appreciated that the various features disclosed in base assemblies  24 ,  124 ,  224 ,  324 ,  424  can be intermixed with one another to provide a base assembly having desired features. Additionally, each of the base assemblies according to the present teachings can include more or less than the features disclosed herein. Moreover, the specific shapes, dimensions, and appearance of the various components can differ from that shown while still providing the advantages and benefits of the present teachings. Thus, the figures used to illustrate the present teachings are merely exemplary in nature and deviations from these illustrations are intended to be within the spirit and scope of the present teachings. 
     LIST OF REFERENCE NUMBERS 
     
         
         
           
               20  power tool/router 
               22  motor unit 
               14  base assembly 
               26  adjustment ring 
               30  head portion 
               32  cylindrical portion 
               33  cord 
               34  switch 
               36  spindle 
               38  collet 
               40  threads 
               41  threads 
               42  axial slot 
               44  projecting feature 
               46  head portion 
               48  stem portion 
               49  openings 
               50  housing 
               51  section 
               52  foot 
               53  aperture 
               54  upper portion 
               55  gap 
               56  clamp assembly 
               57  slot 
               58  interior surface 
               60  recess 
               62  retaining ring 
               64  cylindrical portion 
               66  lip 
               68  depth-indicator ring 
               70  top surface 
               74  top surface 
               76  levers 
               78  tang 
               80  upper end 
               82  pivot 
               83  sloping surface 
               84  sloping surface 
               86  housing 
               87  top surface 
               88  annular recess 
               89  chamfer 
               90  annular recess 
               91  chamfer 
               92  depth-indicator ring 
               94  adjustment ring 
               124  base assembly 
               144  projecting feature 
               150  housing 
               160  recess 
               161  shoulder 
               162  retaining ring 
               166  lip 
               170  top surface 
               172  axial retaining feature 
               173  lip 
               224  base assembly 
               262  retaining ring 
               273  lip 
               274  top surface 
               275  inner wall 
               284  sloping surface 
               324  base assembly 
               350  housing 
               360  recess 
               361  groove 
               362  retaining ring 
               372  axial retaining feature 
               424  base assembly 
               450  housing 
               451  opening 
               454  upper portion 
               485  pivot 
               493  clamping assembly 
               495  clamp spring 
               495   a  end 
               495   b  end 
               497  pivot pin 
               498  clamp lever 
               499  clamp pad