Patent Publication Number: US-2023141146-A1

Title: Portable electrical drilling assembly with reversibly coupled splined shaft

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application No. 63/277,840 filed Nov. 10, 2021 and entitled “Cutter Spline Drive for Portable Electrical Drilling Assembly”, the disclosure of which is herein incorporated by reference in its entirety. 
    
    
     TECHNICAL FIELD 
     The subject application relates, generally, to portable electrical drill assemblies and more particular to a cutter-spline drive for a portable electrical drilling assembly. 
     BACKGROUND 
     Portable electrical drilling assemblies are utilized in many industries for a wide variety of uses. Such portable electrical assemblies typically include an electric motor that is used to allow the portable electrical assembly to perform a particular function. 
     In certain applications, such as for use in deep drilling a workpiece positioned within a confined space surrounded by walls and ceilings or other encumbrances, it is very difficult to drill deep holes within a working surface of a workpiece due to the size and shape of the drilling assembly itself. 
     Moreover, in certain applications where there might be enough clearance to operate the drilling, there may not be enough room to remove various size cutters or reamers used to initially drill the deep holes and subsequently ream the drilled holes to a desired diameter. Drilling such holes is thus an inefficient process requiring makeshift tooling for particular applications. 
     In particular, there are no current commercial off-the-shelf (COTS) portable drills that can meet hole dimension precision parameters with space constraint requirements found in certain applications. Thus, there is a growing need for lightweight, portable electrical drill assemblies that have enough power to drill up to a two-inch diameter hole through up to 6-7 inches of metal such as steel with space constraint requirements found in certain applications. 
     Accordingly, it is desired to provide a portable electrical assembly that addresses two main issues with current COTS portable drills, namely in reducing the drilling assembly footprint for use in confined spaces and providing for alternative drilling methods that reduce the number of steps necessary to achieve a desired final hole dimensional requirement. 
     SUMMARY OF THE DISCLOSURE 
     The subject application is directed to a portable electrical drilling assembly that can be utilized in confined space deep hole drilling applications that addresses the two main issues with current COTS portable drills as described above. 
     In particular, the portable electrical drilling assembly of the subject application is configured to mount to a working surface of a workpiece and is used to drill and subsequently ream holes within the working surface of the workpiece, particularly where the working surface is in a confined space that is difficult to access, such as being in close proximity to a wall and/or roof or another encumbrance. In addition, the portable electrical drilling assembly allows for deep hole drilling in these confined spaces with a full range of up and down travel of the portable electrical drilling assembly which is not possible for most conventional portable electrical drilling assemblies (COTS) due to the need for movement up and down that is limited in these confined spaces. 
     The portable electrical drilling assembly includes an electric motor coupled to a gear box having one or more rotating gears contained within a gear box housing. The drilling assembly also includes a feed mechanism coupled to the gear box and movable relative to the gear box between a plurality of positions including a raised position and a lowered position. The drilling assembly also includes a spindle coupled to the feed mechanism and having an outer ring portion and an inner ring portion positioned within and rotatable relative to the outer ring portion, with the spindle configured to move rectilinearly toward or away from the surface of the workpiece as the feed mechanism moves between the plurality of positions. The drilling assembly also includes a cutting workpiece, such as a cutter or reamer, coupled to said inner ring portion, with the cutting component including an internal surface defining a component cavity. The drilling system also includes a splined shaft connected to one of said gears and rotatable when the one or more gears are rotating, wherein a length of the splined shaft includes a series of splines slidingly received within the component cavity and engaged with the internal surface of the cutting component, with the rotation of the splined shaft rotating the cutting component, and with the rotation of the cutting component rotating the inner ring portion within the outer ring portion of the spindle. 
     The movement of the feed mechanism, with the associated rectilinear movement of the spindle, adjusts the depth of the cutting component within the working surface of the workpiece to control the dimensional requirements of the desired final hole, in terms of depth and diameter, within the working surface. 
     By allowing for the separate connection of the splined shaft and the cutting component prior to the operation of the portable electrical drilling assembly, the drilling assembly footprint can be reduced for use in confined spaces and provides for a method for drilling deep holes having a reduced number of steps necessary to achieve the desired final hole dimensional requirements. 
     The portable electrical drilling assembly allows for the use of different length and dimensioned cutting components for use with a common splined shaft as a part of the cutter-spline drive that therefore allow the assembly to easily drill and ream holes of varying depths and inner radial dimensions using a maximum stroke length of the drilling assembly, as calculated herein in a further embodiment, without increasing the footprint of portable electrical drilling assembly between its raised and lowered positions. 
     Still further, the subject application is directed to an associated method for drilling holes in a surface of workpiece utilizing the portable drilling assembly as described above, including for use in such drilling within a confined space. 
     Even still further, the subject application is also directed to the use of the cutter-spline drive including the combination of the cutting components, and the use of the cutting components described herein alone, in a wide variety of drilling assemblies in addition to the portable electrical drilling assembly described herein. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Other advantages of the subject application will be readily appreciated, as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings. 
         FIG.  1    is a front perspective view of a portable electrical drilling assembly according to one embodiment of the subject application including a feed mechanism having a pneumatic actuator and associated components with the portable electrical drilling assembly in a raised position and positioned onto a working surface of a workpiece to be drilled within a confined space; 
         FIG.  2 A  is a front perspective and partial section view of a cutter of  FIG.  1    engaged with the splined shaft and with the cutter having a length L 1 ′; 
         FIG.  2 B  is a section view of  FIG.  2 A  taken along line  2 B- 2 B; 
         FIG.  2 C  is a section view of  FIG.  2 D  taken along line  2 C- 2 C; 
         FIG.  2 D  is a front perspective and partial section view of a cutter of  FIG.  1    engaged with the splined shaft and with the cutter having a length L 1 ″; 
         FIG.  2 E  is a front perspective and partial section view of a reamer of  FIG.  1    engaged with the splined shaft and with the reamer having a length L 2 ′; 
         FIG.  2 F  is a section view of  FIG.  2 E  taken along line  2 F- 2 F; 
         FIG.  2 G  is a section view of  FIG.  2 H  taken along line  2 G- 2 G; 
         FIG.  2 H  is a front perspective and partial section view of a reamer of  FIG.  1    engaged with the splined shaft and with the reamer having a length L 2 ″; 
         FIG.  3 A  is a front and close-up perspective view of the portable drilling assembly of  FIG.  1    including the cutter of  FIG.  2 A  in a raised position and positioned over a pilot hole predrilled into the working surface of the workpiece to be drilled; 
         FIG.  3 B  is a close-up perspective view of the portable drilling assembly of  FIG.  3 A  within circle  3 B; 
         FIG.  4 A  is a front and close-up perspective view of the portable drilling assembly of  FIG.  3 A  in an intermediate position with the cutter of  FIG.  2 A  positioned within a pilot hole of the working surface; 
         FIG.  4 B  is a close-up perspective view of the portable drilling assembly of  FIG.  4 A  within circle  4 B; 
         FIG.  5    is a front perspective view of the portable drilling assembly of  FIG.  3 A  in a lowered position with the cutter of  FIG.  2 A  positioned within a drilled hole beneath the pilot hole in the working surface; 
         FIG.  6    is a front perspective view of the portable drilling assembly of  FIG.  5    in the raised position with the cutter of  FIG.  2 A  positioned above the drilled hole and above the pilot hole in the working surface with a slug remaining in the drilled hole; 
         FIG.  7    is a front perspective view of  FIG.  6    with the portable assembly removed illustrating the removal of the slug from the drilled hole and pilot hole; 
         FIG.  8    is a perspective view of the portable drilling assembly of  FIG.  6    in the raised position with the cutter of  FIG.  2 A  removed and with the cutter of  FIG.  2 D  positioned within a drilled hole and the pilot hole in the working surface prior to connecting the cutter of  FIG.  2 A  to the spindle and prior to connecting the splined shaft to the gear in the gear housing; 
         FIG.  9    is a perspective view of the portable drilling assembly of  FIG.  8    in an intermediate position with the cutter of  FIG.  2 D  positioned within a drilled hole and the pilot hole in the working surface after connecting the cutter of  FIG.  2 D  to the spindle and prior to connecting the splined shaft to the gear in the gear housing; 
         FIG.  10    is a perspective view of the portable drilling assembly of  FIG.  9    moved to the lowered position within a further drilled hole in the working surface of the workpiece; 
         FIG.  11 A  is a perspective view of the splined shaft aligned to the gear in the gear box housing in an uncoupled position; 
         FIG.  11 B  is a perspective view of the splined shaft aligned to the gear in the gear box housing of  FIG.  11 A  in a coupled position but uncoupled state; 
         FIG.  11 C  is a perspective view of the splined shaft aligned to the gear in the gear box housing of  FIG.  11 A  in the coupled position and coupled state; 
         FIG.  12    is a perspective view of the portable drilling assembly of  FIG.  9    moved to the raised position within the further drilled hole present in the working surface of the workpiece; 
         FIG.  13 A  is a front and close-up perspective view of the portable drilling assembly of  FIG.  12    in the raised position with the reamer of  FIG.  2 E  coupled to the spindle and positioned above the pilot hole and further drilled hole of the working surface; 
         FIG.  13 B  is a close-up perspective view of the portable drilling assembly of  FIG.  13 A  within circle  13 B; 
         FIG.  14 A  is a front and close-up perspective view of the portable drilling assembly of  FIG.  13 A  in an intermediate position with the reamer of  FIG.  2 E  coupled to the spindle and positioned to be extending within the pilot hole of the working surface; 
         FIG.  14 B  is a close-up perspective view of the portable drilling assembly of  FIG.  14 A  within circle  14 B; 
         FIG.  15    is a front and close-up perspective view of the portable drilling assembly of  FIG.  14 A  in the lowered position with the reamer of  FIG.  2 E  coupled to the spindle and positioned to be extending within the reamed pilot hole and the further reamed and drilled hole of the working surface; 
         FIG.  16    is a front and close-up perspective view of the portable drilling assembly of  FIG.  15    returned to the raised position from the lowered position with the reamer of  FIG.  2 E  coupled to the spindle and positioned to be extending above the reamed pilot hole and the further reamed and drilled hole of the working surface; 
         FIG.  17    is a perspective view of the further reamed and drilled hole of  FIG.  16    with the portable drilling assembly removed; 
         FIG.  18    is a front perspective view of the reamer of  FIG.  2 G  positioned to be extending within the reamed pilot hole and reamed and drilled hole of the working surface of  FIG.  17   ; 
         FIG.  19    is a perspective view of the portable drilling assembly of  FIG.  18    in the raised position with the reamer of  FIG.  2 H  positioned within the reamed and drilled hole and within the reamed pilot hole in the working surface prior to connecting the reamer of  FIG.  2 G  being connected to the spindle and prior to connecting the splined shaft to the gear in the gear housing; 
         FIG.  20    is a perspective view of the portable drilling assembly of  FIG.  19    in an intermediate position with the reamer of  FIG.  2 H  positioned within the reamed and drilled hole and within the reamed pilot hole in the working surface after connecting the reamer of  FIG.  2 G  to the spindle and prior to connecting the splined shaft to the gear in the gear housing; 
         FIG.  21    is a perspective view of the portable drilling assembly of  FIG.  21    moved to the lowered position within the further reamed and drilled hole and within the reamed pilot hole in the working surface of the workpiece after connecting the reamer of  FIG.  2 H  to the spindle and after connecting the splined shaft to the gear in the gear housing; 
         FIG.  22    is a front and close-up perspective view of the portable drilling assembly of  FIG.  21    returned to the raised position from the lowered position with the reamer of  FIG.  2 H  coupled to the spindle and positioned to be extending above the further reamed pilot hole and the still further reamed and drilled hole of the working surface; 
         FIG.  23    is a perspective view of the portable drilling assembly of  FIG.  22    illustrating the stoke length of the portable drilling assembly between the raised and lowered position that includes the splined shaft quick connected to the gear and also showing the reamer of  FIG.  2 H  coupled to the spindle; 
         FIG.  24    is a perspective view of a portable drilling assembly in accordance with another exemplary embodiment including a feed mechanism that replaces the pneumatic actuator and associated components with a movable handle and with the portable drilling assembly including the cutter of  FIG.  2 A  in a raised position and after connecting the splined shaft to the gear in the gear housing; 
         FIG.  25    is a perspective view of the portable drilling assembly of  FIG.  24    moved to a lowered position from the raised position and after connecting the splined shaft to the gear in the gear housing; 
         FIG.  26    is a perspective view of the handle of  FIGS.  24 - 26    detached from the remainder of the portable drilling assembly and after connecting the splined shaft to the gear in the gear housing; 
         FIG.  27    is a perspective view of a portable drilling assembly in accordance with another exemplary embodiment including a feed mechanism that replaces the pneumatic actuator and associated components with an electric feed mechanism having associated components and with the portable drilling assembly including the cutter of  FIG.  2 A  in a raised position and after connecting the splined shaft to the gear in the gear housing; 
         FIG.  28    is a front and close-up perspective view of the portable drilling assembly of  FIG.  27    in an intermediate position with the cutter of  FIG.  2 A  positioned within a pilot hole of the working surface; and 
         FIG.  29    is a front perspective view of the portable drilling assembly of  FIG.  27    in a lowered position with the cutter of  FIG.  2 A  positioned within a drilled hole beneath the pilot hole in the working surface. 
     
    
    
     DETAILED DESCRIPTION 
     Referring now to Figures, wherein like numerals indicate corresponding parts throughout the several views, a portable electrical drilling assembly, illustrated and described hereinafter in one exemplary embodiment as a magnetically mountable portable electric drill machine (“magdrill”), is shown generally at  20 . 
     Referring generally to  FIG.  1   , the portable electrical drilling assembly  20  (sometimes referred to hereinafter as drilling assembly  20  or more simply as an assembly  20 ) in accordance with one exemplary embodiment is configured to mount to a working surface  30  of a workpiece  32  and is used to drill and subsequently ream holes within the working surface  30  of the workpiece  32 , particularly where the working surface  30  is in a confined space that is difficult to access, such as being in close proximity to a wall  40  and/or roof  45  or another encumbrance (i.e., within a confined space  50 ). In addition, the portable electrical drilling assembly  20  allows for deep hole drilling in these confined spaces  50  with a full range of up and down travel of the portable electrical drilling assembly  20  which is not possible for most conventional portable electrical drilling assemblies due to the need for movement up and down that is limited in these confined spaces. 
     The portable electrical drilling assembly  20  includes, as its major components, an electric motor  60  (sometimes referred to simply as a motor  60 ) having a motor housing  61  with the motor  60  coupled to a gear box  62  having one or more rotating gears  63  (see  FIG.  11   ) contained within a gear box housing  64 . The gear box housing  64  includes an electrical connector  66  for coupling an electrical power source (not shown) to the electric motor  60 , with the actuation of the electrical power source by a user/operator functioning to initiate the motor  60  to rotate the gears  63  contained within the gear box housing  64 . The motor housing  61  may include one or more vents  69  that function to provide an air passage for aiding in cooling the electric motor  60  during operation. 
     As best shown in  FIGS.  11 A,  11 B, and  11 C , the gear box  62  and/or the gear  63  also includes an internal quick connection mechanism  65  (sometimes referred to alternatively as a quick connector  65 ) for connecting to a corresponding turned and milled upper end feature  72  of a splined shaft  70  to the gear  63 . In certain embodiments, such as best shown in  FIGS.  11 A,  11 B, and  11 C , the internal quick connection mechanism  65  includes a steel pin  67  that is positioned within an internal opening  63 A of the gear  63 , although in other embodiments the quick connection mechanism  65  may be include a ball bearing (not shown) contained within another portion of the gear housing  64  in proximity to the gear  63 . The length of the splined shaft  70  includes a series of splines  74  extending along its outer circumferential surface  79  (see  FIG.  5   ) that extend between a turned and milled upper end feature  72  to a bottom end  76 . The turned and milled upper end feature  72 , in accordance with certain embodiments and as illustrated in the Figures, includes an inwardly extending recessed portion  73  contained within the outer circumferential surface  79  of the splined shaft  70 . Still further, a portion of the inwardly extending recessed portion  73  includes a ledge  77  (see  FIG.  11 C ) extending radially outwardly, with the outward surface  77 A of the ledge  77  aligned with the outer circumferential surface  79  of the splined shaft closer to the bottom end  76 . 
     Returning back to  FIG.  1   , in certain embodiments, the drilling assembly  20  also includes a feed mechanism  80  having a mechanism housing  82  pivotally coupled to the gear box housing  64  with a fastening mechanism  84 , here shown as a pin  84  contained within a slot  86  defined by the mechanism housing  82 . The feed mechanism  80  includes a pinion gear  88  rotatably coupled and engaged to a rack  90 . The drilling assembly  20  also includes a spindle  92 , preferably a ring-shaped spindle  92  having an outer fixed portion  93 , coupled to an end  94  of the mechanism housing  82  generally adjacent to the pinion gear  88 . The spindle  92  also includes an inner ring portion  95  contained within the outer fixed portion  93  which is rotatable relative to the outer fixed portion  95 . In particular, the pinion gear  88  is engaged (i.e., intermeshed) with the teeth  91  of the rack  90  and moves along the rack  90  as it rotates to achieve rectilinear movement of both the pinion gear  88  and the spindle  92  (i.e., up and down movement as illustrated in the Figures) during a drilling operation. The inner ring portion  95  of the ring shaped spindle  92  has an internal diameter sized to receive a connection portion  124 ,  144  of a respective cutter  110  (see  FIGS.  2 A- 2 D ) or reamer  130  (see  FIGS.  2 E- 2 H ) (collectively or alternatively referred to as a cutting component  110  or  130 ) and includes a set screw  97  (see  FIGS.  11 A-C ) to reversibly connect the inner ring portion  95  to the connection portion  124 ,  144  of a respective cutter  110  or reamer  130 . 
     In the embodiment shown in  FIGS.  1 ,  3 - 10 , and  12 - 23   , the feed mechanism  80  includes a pneumatic actuator  96  and a series of feed gears that are intermeshed to the pinion gear  88  along the length of a slide assembly  100  (a single feed gear  98  is visible, but additional feed gears (not shown) are contained internally within the slide assembly  100 ) that is partially defined by the mechanism housing  82 . The pneumatic actuator  96  utilizes an air-driven piston to rotate the plurality of feed gears, including the feed gear  98 , and pinion gear along the length of the slide assembly  100 . 
     The rotation of the feed gears (including feed gear  98 ) and pinion gear  88  along the length of the slide assembly  100  results in a desired rectilinear movement (i.e., up and down movement) of the spindle  92  as the pinion gear moves along the rack  90  when the pneumatics of the feed mechanism  80  are actuated through the pneumatic actuator  96  by a user/operator, such as through the actuation of a switch or push button (not shown) of the pneumatic actuator  96  to assist in pivoting the feed mechanism  80  about an axis defined by the pin  84 . 
     In an alternative embodiment, shown in  FIGS.  24 - 26   , the feed mechanism  80  does not include the pneumatic actuator  96  and associated feed gears  98  as described above and is instead in the form of a moveable handle  250  that is coupled to the gear box housing  64  or another portion of the drilling assembly  20  and that also includes the pinion gear  88  coupled to the rack  90  as illustrated above. In this embodiment, a user/operator simply applies force to the handle  250  in a direction transverse to the length L of the handle  250  defined between a gripping end  229  and a coupling end  231 , thereby allowing the handle  250  to rotate in a first rotational direction or second rotational direction depending upon the direction of force applied, which in turn rotates the coupled pinion gear  88  and corresponding desired rectilinear movement the pinion gear  88  along the rack  90 , while also achieving rectilinear movement of the spindle  92  (i.e., up and down movement as shown in  FIGS.  24 - 26   ) in the same manner as the pneumatic operations of the first embodiment shown in  FIGS.  1 ,  3 - 10 , and  12 - 23   , during a drilling operation. The drilling operations in accordance with the present disclosure therefore utilize either the feed mechanism  80  with the pneumatic system including the pneumatic actuator  96  as shown in the first embodiment shown in  FIGS.  1 ,  3 - 10 , and  12 - 23   , or with movable handle  250 , as described in the embodiment of  FIGS.  24 - 26   , with each described further below. 
     In the embodiment of  FIGS.  24 - 26   , the coupling end  231  of the handle  250  defines an opening  233  through which a pin  235  extends that pivotally couples the pinion gear  88  to the coupling end  231  of the handle  250  such that the pinion gear  88  freely rotates within the opening  233  about an axis defined by the length of the pin  235  in coordination with the handle  250  as the handle  250  is rotated. The coupling end  231  also defines a secondary opening  237  through which a ratchet mechanism  239  is provided, with the ratchet mechanism pivoting within the secondary opening  237  about an axis defined by the secondary opening  237  between a first ratchet position and a second ratchet position. The ratchet mechanism  239  is pivoted to the first ratchet position (or upward ratchet position) when a user/operator wants to rotate the handle  250  in a first rotational direction such that the spindle  92  and cutting component (i.e., the cutter  110  or reamer  130 ) moves in a direction away from the working surface  30 , while the second ratchet position is utilized when the user/operator wants to rotate the handle  250  such that the spindle  92  and cutting component moves in a direction towards the working surface  30 . 
     Accordingly, the pivoting movement of the handle  250  in a first rotational direction (shown as clockwise movement when comparing the movement shown consecutively in  FIGS.  24 ,  25  and  26   ) in turn rotates the gear  88 , which moves along the rack  90  in coordination with the movement of the spindle  92  away from the working surface  30 , and the movement of the spindle  92  away from the working surface  30  in turn moves the coupled cutting component away from the working surface in response. Alternatively, the pivoting movement of the handle  250  in a second rotational direction (i.e., a counterclockwise movement of the handle when comparing the movement shown consecutively in  FIGS.  26 ,  25  and  24   ) in turn rotates the gear  88 , which moves along the rack  90  in coordination with the movement of the spindle  92  towards from the working surface  30 , and the movement of the spindle  92  towards the working surface  30  in turn moves the coupled cutting component towards the working surface  30  in response to allow the drilling or reaming of a hole, as will be described further below. 
     In still another alternative embodiment, as shown in  FIGS.  27 - 29    below, the feed mechanism  80  does not include the pneumatic actuator  96  and associated feed gears  98  as described above in  FIGS.  1 ,  3 - 10 , and  12 - 23    and does not include the manually moveable handle  250  as shown in  FIGS.  24 - 26   , but is instead in the form of an electric feed mechanism  280  that also includes the pinion gear  88  coupled to the rack  90  as illustrated above. In this embodiment, as will be described in further detail below, a user/operator simply actuates the electric feed mechanism  280  in a manner that results in the rotation of feed gears, including feed gear  98 , and the coupled pinion gear  88  and corresponding desired rectilinear movement the pinion gear  88  along the rack  90 , while also achieving rectilinear movement of the spindle  92  (i.e., up and down movement as shown in  FIGS.  27 - 29   ) in the same manner as the pneumatic operations of the first embodiment shown in  FIGS.  1 ,  3 - 10 , and  12 - 23    and the manual movement of the handle  250  in second embodiment shown in  FIG.  24 - 26    during a drilling operation. 
     The drilling assembly  20  also preferably includes a magnetic base  105  coupled to a lower portion  68  of the gear box housing  64 . The magnetic base  105  includes an on/off control switch (not shown) that is configured for operation by a user/operator to turn on the magnetic base  105  to generate a magnetic field or turn off the magnetic base  105  to remove the magnetic field. 
     The drilling assembly  20  also includes one or more cutter splined shaft assemblies  110 , or cutters  110  and sometimes referred to as annular cutters  110 , and one or more reamer splined shaft assemblies  130 , or reamers  130  and sometimes referred to as annular reamers  330 , having predefined lengths L 1  and L 2 , respectively, that are used to drill holes of varying depths and diameters in the working surface  30 . The cutters  110  and reamers  130 , in combination with the splined shaft  70  described above with the interrelationship described in the subject application, may herein be collectively and alternatively be referred to as a “cutter-spline drive”. 
     As best shown in  FIGS.  2 A- 2 D , and representative of one non-limiting exemplary embodiment, the drilling assembly  20  includes two cutters  110  having varying lengths L 1 ′ and L 1 ″, corresponding to a shorter cutter  112  of length L 1 ′ (see  FIG.  2 A ) and a longer cutter  114  of length L 1 ″ (see  FIG.  2 D ). As also shown in  FIGS.  2 E- 2 H  and representative of one non-limiting exemplary embodiment, the drilling assembly  20  includes two reamers  130  having varying lengths L 2 ′ and L 2 ″, corresponding to a shorter reamer  132  of length L 2 ′ (see  FIG.  2 E ) and a longer reamer  134  of length L 2 ″ (see  FIG.  2 H ). The number of cutters  110  and reamers  130  for interchangeable use in the portable drilling assembly  20  can vary between one and more than one and can vary in length from the cutters  110 ,  112 ,  114  and reamers  130 ,  132 ,  134  illustrated herein. 
     As best shown in  FIG.  2 B , each of the cutters  110 ,  112 ,  114  also defines an internal surface  106  that includes splined regions  108  that extend internally along a portion of their respective lengths L 1 , L 1 ′, L 1 ″ that are sized and shaped to accept the series of splines  74  of the splined shaft  70  therewithin during use. For ease of illustration,  FIG.  2 B  illustrates a section view of the shorter cutter  112 , but the same section could be illustrated from the longer cutter  114  of  FIG.  2 D . Accordingly, and owing to the presence of internal surface  106  that therefore defines a component cavity contained within the respective cutter  110 ,  112 ,  114 , each of the cutters  110 ,  112 ,  114  may also be referred to alternatively as hollow cutters  110 ,  112 ,  114 . When the series of splines  74  of the splined shaft  70  are accepted within the internal surface  106  and engage the splined regions  108  to form the cutter-spline drive, the rotation of the splined shaft  70  therefore results in the rotation of the coupled cutter  110 ,  112 ,  114  in the same rotational direction. 
     In addition, the outer surface  116  of the length each of the cutters  110 ,  112 ,  114  includes a plurality of helically twisted flutes  118  extending from a bottom end  120  to an intermediate portion  122 . Still further, the outer surface  116  of the length each of the cutters  110 ,  112 ,  114  also includes a connection portion  124  extending from the intermediate portion  122  to a top end  126 . While not illustrated, additional cutters  110  longer than L 1 ″ can also be utilized in the subject application. 
     As one of ordinary still recognizes, the plurality of helically twisted flutes  118  are configured to allow the cutters  110 ,  112 ,  114  to be utilized as an initially drilling step to drill a drilled hole in a working surface  30  by allowing drilled material along the outer diameter of the drilled hole to be easily removed as the cutter  110 ,  112 ,  114  moves to depths deeper in the work surface  30  than flute designs extending lengthwise and untwisted along the length. 
     In certain embodiments, as shown in the section view of  FIG.  2 C , a portion of the internal surface  106  near the bottom end  120  may be substantially smooth and not include the splined regions  108  so as to minimize frictional engagement between the series of splines  74  and the corresponding splined regions  108  and increase the durability of the respective splined shaft  70  and cutter  110 ,  112 ,  114  during usage. For ease of illustration,  FIG.  2 C  illustrates a section view of the shorter cutter  112 , but the same section could be illustrated from the longer cutter  114  of  FIG.  2 D . 
     Similarly, and as illustrated in  FIGS.  2 E- 2 H , each of the reamers  130 ,  132 ,  134  defines an internal surface  136  that includes splined regions  137  that extend internally along their respective lengths L 2 , L 2 ′, L 2 ″ that are sized and shaped to accept the series of splines  74  of the splined shaft  70  therewithin during use. For ease of illustration,  FIG.  2 F  illustrates a section view of the shorter reamer  132 , but the same section could be illustrated from the longer reamer  134  of  FIG.  2 H . Accordingly, and owing to the presence of internal surface  136  that therefore defines a component cavity within respective reamer  130 ,  132 ,  134 , each of the reamers  130 ,  132 ,  134  may also be referred to alternatively as hollow reamers  130 ,  132 ,  134 . When the series of splines  74  of the splined shaft  70  are accepted within the internal surface  136  to form the cutter-spline drive (i.e., reamer-spline drive), the rotation of the splined shaft  70  therefore results in the rotation of the coupled reamer  130 ,  132 ,  134  in the same rotational direction. 
     However, the outer surface  139  of the length each of the reamers  130 ,  132 ,  134  includes a plurality of untwisted and lengthwise extending flutes  138  extending from a bottom end  140  to an intermediate portion  142 . Still further, the outer surface  139  of the length each of the reamers  130 ,  132 ,  134  also includes a connection portion  144  extending from the intermediate portion  142  to a top end  146 . While not illustrated, additional reamers  130  longer than L 2 ″ can also be utilized in the subject application. As one of ordinary still recognizes, the use of untwisted and lengthwise extending flutes  138  are configured to allow the reamers  130 ,  132 ,  134  to be utilized in a subsequent drilling step in conjunction with a cutter  110  to provide a more precisely circular drilled hole in cross-sectional diameter to the drilled hole provided originally by the cutter. 
     In certain embodiments, as shown in the section view of  FIG.  2 G , a portion of the internal surface  136  near the bottom end  140  may be substantially smooth and not include the splined regions  137  so as to minimize frictional engagement between the series of splines  74  and the corresponding splined regions  137  and increase the durability of the respective splined shaft  70  and reamer  130 ,  132 ,  134  during usage. For ease of illustration,  FIG.  2 G  illustrates a section view of the shorter reamer  132 , but the same section could be illustrated from the longer reamer  134  of  FIG.  2 H . 
     In each of the illustrated embodiments, as best shown in respective  FIGS.  2 B,  2 C,  2 F and  2 G , the respective cross-sectional diameters of the cutters  112 ,  114  and reamers  132 ,  134  is the same. However, in embodiments not illustrated, additional cutters  110  and/or reamers  130  having differing cross-sectional diameters from  FIGS.  2 B,  2 C,  2 F and  2 G  are contemplated for use in the drilling assembly  20  of the subject application. 
     Still further, in each of the illustrated embodiments, while the drawings illustrate the cutting components (i.e., the cutters  110  and/or reamers  130 ) having a particular illustrated dimension in terms of length L 1 , L 1 ′, L 1 ″ or L 2 , L 2 ′, L 2 ″ relative to each other and to the size of the components of the drilling assembly  20 , such dimensions should not be construed as limiting. Various other lengths of the cutters  110  and/or reamers  130  relative to each other (in combination with additional cross-sectional diameters) and to the components of the drilling assembly  20  are contemplated. 
     The working surface  30  may be any suitable shape, such as a rectangular shape and is typically made of a ferromagnetic material such as steel. The portable electric drilling assembly  20  is typically mounted and secured to the working surface  30  by magnetic attraction between the magnetic base  105  and the working surface  30 . The portable electric drilling assembly  20  may also alternatively be mounted or otherwise secured to the working surface with a clamp or through the use of a vacuum assist. Still further, the portable electric drilling assembly  20  may be mounted or secured to the working surface  30  by magnetic attraction in combination clamping and/or vacuum assist. It should be appreciated that the working surface  30  may be a workpiece, or the workpiece may be supported on the working surface  30 . It should also be appreciated that the working surface  30  is not intended to limit the scope of the subject application. It should further be appreciated that the portable electric drilling assembly  20  may be used with various other types of working surfaces without departing from the scope of the subject application. 
       FIGS.  3 - 10  and  12 - 22    illustrate an operational method for utilizing the portable electric drilling assembly  20  of  FIG.  1    to drill and subsequently ream a hole into the working surface  30  of a workpiece  32  utilizing the two cutters  112 ,  114  and two reamers  132 ,  134  illustrated in  FIGS.  2 A- 2 H  of the subject application. The operations of  FIGS.  3 - 10  and  12 - 22    are ideally suited for drilling such holes in workpieces  32  within a confined space  50 , although the operation of the drilling assembly  20  in accordance with the description of  FIGS.  3 - 10  and  12 - 22    can also be performed on workpieces not in a confined space. 
     In general, during this operational method, when the workpiece  32  is a metal workpiece, the portable electric drilling assembly  20  is disposed on the working surface  30 , such as wherein the workpiece  32  is situated in the confined space  50 . The user/operator operates a control switch (not shown) to provide power to generate a magnetic field to magnetically mount and secure the magnetic base  105  of the portable electric drilling assembly  20  to the working surface  30 . The user/operator actuates the electric motor  60  and the electric motor  60  rotates about a drive axis and rotates the gear  63  contained within the gear housing  64 , which in turn rotates the splined shaft  70  quick connected to the gear  63  via the quick connection mechanism  65  within the gear housing  64 . At the same time, the intermeshing of the splines  74  of the splined shaft  70  with the splined regions  108  of the internal surface  106  causes the attached cutter  110 ,  112 ,  114  (or the intermeshing of the splines  74  of the splined shaft  70  with the splined regions  137  of the internal surface  136  of the attached reamer  130 ,  132 ,  134 ) to rotate in response and drill or ream the hole to a desired cross-sectional diameter. Still further, by pivoting the feed mechanism  80  from a raised position to an intermediate or lowered position, the depth of the drilled or reamed hole can be precisely controlled, with the maximum depth corresponding to the stroke length associated with the pivoting the feed mechanism  80  from a raised position to the lowered position as described further below. 
     Referring first to  FIGS.  3 A and  3 B , the operational method begins wherein a first cutter  110  (here shown as the smaller cutter  112 ) is positioned above a pilot hole  200  with the connection portion  124  of the cutter  112  received within the internal diameter of the spindle  92  and with the pivoting feed mechanism  80  positioned in the raised position wherein the spindle  92  is positioned in its closest proximity to the gear  63  and in its furthest proximity from the working surface  30  of the workpiece  32  and pilot hole  200 . The pilot hole  200  has been predrilled into the working surface  30  and provides an orientation for guide for the drilling of the hole as provided in the operational method. In this position, the bottom end  120  of the cutter  110 ,  112 , is positioned adjacent to the opening defining the pilot hole  200  at the working surface  30 , and the user/operator inserts and tightens the set screw  97  (see  FIGS.  11 A-C ), typically with an Allen wrench, to reversibly couple the connection portion  124  of the cutter  110 ,  112  to the inner ring portion  95  of the spindle  92 . As one of skill appreciates, by loosening the set screw  97 , the process of coupling the connection portion  124  of the cutter  110 ,  112  to the inner ring portion  95  of the spindle  92  can be reversed. 
     In addition, the splined shaft  70  is quick connected to the gear  63  via the quick connection mechanism  65 , as also best shown in  FIGS.  11 A- 11 C . In particular, the splined shaft  70  is first aligned with and positioned beneath the gear  63  which includes a quick connect mechanism  65  by the user/operator, as shown in  FIG.  11 A , by twisting the splined shaft  70  in a clockwise or counterclockwise direction until the splines  74  of the splined shaft  70  are aligned with the internal opening  63 A within the gear  63  and with the inwardly extending recessed portion  73  not including the ledge  77  aligned beneath the steel pin  67 . Next, as shown in  FIG.  11 B , the user/operator inserts the turned and milled upper end feature  72  of the splined shaft  70  within the internal opening  63 A of the gear  63  by moving the splined shaft  70  towards the gear  63  (shown by arrow  71 ) such that the turned and milled upper end feature  72  of the splined shaft  70  is contained within the internal opening  63 A within the gear  63 . Finally, the splined shaft  70  is rotated a quarter turn (shown by arrow  81 ), thereby positioning the ledge  77  adjacent to and above the quick connect feature  65  (i.e., above the steel pin  67 ). In this position, the splined shaft  70  cannot be pulled in a direction away from the gear  63  and gear housing  64  towards the working surface  30  because the ledge  77  is prevented from moving by the quick connect mechanism  65 , here the steel pin  67 . In the connected position, the gear  63  is engaged with the splined shaft  70 , and hence the splined shaft  70  rotates as the plurality of gears  63  are rotated. 
     To disconnect the splined shaft  70  from the quick connect feature  65  and remove the splined shaft  70  from engagement with the gear  63 , the user rotates the splined shaft  70  a quarter turn in the opposite direction of arrow  81 , at which point the inwardly extending recessed portion  73  is aligned with the steel pin  67  but wherein the ledge  77  is not above the steel pin  67  of the quick connect feature  65 , which allows the user/operator to move the splined shaft  70  away from the gear box  64  towards the working surface  30  (i.e., in an opposite direction to arrow  71  shown in  FIG.  11 B ) to the unconnected position as shown in  FIG.  11 A . 
     Referring back to  FIGS.  3 A and  3 B , and while not illustrated specifically in these figures, it is understood that a maximum length of the splined shaft  70  (hidden within the cutter  110 ,  112  as illustrated) is received within the component cavity defined by the internal surface  106  of the cutter  110 ,  112 . 
     Next, the user/operator operates a control switch (not shown) to provide power to generate a magnetic field to magnetically mount and secure the magnetic base  105  of the portable electric drilling assembly  20  to the working surface  30 . The user/operator actuates the electric motor  60  and the electric motor  60  rotates about a drive axis and rotates the gear  63  contained within the gear housing  64 , which in turn rotates the splined shaft  70  quick connected to the gear  63  within the gear housing  64 . At the same time, the intermeshing of the splines  74  of the splined shaft  70  with the splined regions  108  of the internal surface  106  causes the attached cutter  110 ,  112  (and inner ring portion  95  contained within the fixed outer portion  93  of the spindle  92 ) to rotate in response. Stated another way, the rotation of the splined shaft  70  directly drives the rotation of the attached cutter  110 ,  112  which drives the rotation of the inner ring portion  95 . 
     Next, as shown in  FIGS.  4 A- 4 B and  5   , the user/operator pivots the feed mechanism  80  (by actuating the pneumatic actuator  96 ) from the raised position (as shown in  FIGS.  3 A and  3 B ) through an intermediate position (as shown in  FIGS.  4 A and  4 B ) to a lowered position (as shown in  FIG.  5   ). The pivoting of the feed mechanism  80  relative to the gear housing  64  is accomplished by actuating the pneumatic actuator  96  to rotate the plurality of feed gears (including feed gear  98 ) which in turn causes the pinion gear  88  to rotate in response and move in a rectilinear movement away from the gear  63  and towards the working surface  30  (downward as shown in  FIG.  4 A ) while remaining intermeshed with the teeth  91  in the rack  90 . The rotation of the cutter  110 ,  112  (caused by the rotation of the coupled splined shaft  70  and gear  63  rotated by the motor  60 ) during this movement from the raised position through the intermediate position to the lowered position drills a secondary hole  210  in the workpiece  32  of increasing depth in a direction away from the working surface  30  that is axially aligned with the pilot hole  200  (as best shown in  FIG.  4 B  and  FIG.  5   ). In other words, the relative amount of pivoting of the feed mechanism  80  from the raised position (as shown in  FIGS.  3 A and  3 B ) through an intermediate position (as shown in  FIGS.  4 A- 4 B ) to a lowered position (as shown in  FIG.  5   ) controls the relative depth of the secondary hole  210  drilled. 
     The depth of the secondary hole  210  beneath the pilot hole  200  is a function of a stroke length of the drilling assembly  20  with the attached cutter  110 ,  112  pivoted to the lowered position. In particular, the stroke length is defined as the length of movement of the spindle  92  between any two operating positions between and including the raised and lowered positions and may be determined by subtracting the height of the spindle  92  relative to the working surface  30  in a second operating position from the height of the spindle  92  relative to the working surface  30  in a first operating position, with the second operating position of the spindle  92  being closer to the working surface  30  than the first operating position of the spindle  92 . 
     The maximum depth of the secondary hole  210  beneath the pilot hole  200 , which is shown in  FIG.  5    (or a maximum depth of a tertiary hole  220  as in  FIG.  23   ), may be defined in terms of the maximum stroke length  300  of the drilling assembly  20  that is calculated by subtracting the gearbox height  305 , the spindle height  310  and the chip clearance height  315  from the machine height  320  in the lowered position. In this calculation, the machine height  320  is fixed and is defined as the distance between the top of the gear box housing  64  and the working surface. Similarly, the gearbox height  305  is also fixed, and is defined as the distance between the top of the gear box housing and the bottom of the gear box housing  64  associated with portion of the gear box  62  including the quick connection mechanism  65 . The spindle height  310  is further defined as the distance between the upper and lower surface of the spindle  92 , while the chip clearance height  315  is further defined as the distance between the bottom of the spindle  92  and the working surface  30  of the workpiece  32  in the lowered position. 
     As also shown in  FIG.  5   , the positioning of the feed mechanism  80  in the lowered position is such wherein a minimum length of the splined shaft  70  is received within the component cavity defined by the internal surface  106  of the cutter  110 ,  112 , but wherein this minimum length still results in the engagement of the splines  74  of the splined shaft  70  with the corresponding splined regions  108  of the internal surface  106  of the cutter  110 ,  112 , and thus the rotation of the splined shaft  70  results in the rotation of the attached cutter  110 ,  112  as described above. 
     Once the drilling assembly  20  reaches the lowered position, as in  FIG.  5    and completes the drilling of the secondary hole  210  and corresponding to the maximum stroke  300  in circumstances where the drilling assembly began in the raised position, the user/operator pivots the feed mechanism  80  (by actuating the pneumatic actuator  96 ) back to the raised position, as shown in  FIG.  6   . The user/operator then turns off the electric motor  60  and then turns off the magnetic base  105  and moves the drilling assembly  20  away from the drilled secondary hole  210  from the lowered position to the raised position. The cutter  110 ,  112  can then be uncoupled (i.e., decoupled) from inner ring portion  95  of the spindle  92  by turning the set screw  97 , typically using an Allen wrench, such that it is out of contact with the connection portion  124  of the first cutter  112 , and the splined shaft  70  may optionally be unconnected from the quick connect mechanism of the gear  63 . The first cutter  112  can then be removed from the secondary hole  210 . 
     As also shown in  FIG.  6   , a slug  230  remains within the secondary hole  210  that includes the drilled workpiece  32  material. As shown in  FIG.  7   , and before or after removal of the first cutter  110 ,  112  from the spindle  92  but after the movement of the first cutter  110 ,  112  to a position not within the secondary hole  210  and pilot hole  200 , the user/operator removes the slug  230  from the secondary hole  210  through the pilot hole  200 . 
     In operations wherein a deeper hole than the secondary hole  210  is desired in the workpiece  32 , the operational method of the subject application may further include a second drilling step, as illustrated in  FIGS.  8 - 12    below. 
     Referring now to  FIG.  8   , after the first cutter  110 ,  112  has been decoupled from the drilling assembly  20  and removed from the drilled secondary hole  210 , as described above in  FIGS.  5  and  6   , a second cutter  110 ,  114 , here shown as the longer cutter  114 , is positioned within the secondary hole  210  with the bottom end  120  seated at the bottom  211  of the secondary hole  210  and with the connection portion  124  exposed and spaced beneath the spindle  92 , which has preferably been raised along with the feed mechanism  80  to a raised position or to an additional intermediate position above the lowered position. 
     During and preferably prior to this positioning of the second cutter  110 ,  114  in the secondary hole  210 , the user/operator raises the splined shaft  70  such that it can be quick connected to the gear  63  via the quick connection mechanism  65  in the same manner described above with respect to  FIG.  3 A  and  FIG.  11   . 
     Notably, the maximum length of the second cutter  114  that can be introduced as illustrated in  FIG.  8    when the drilling assembly  20  is in the raised position is limited by the distance between the bottom end  76  of the splined shaft  70  and the bottom  211  of the secondary hole  210  when the splined shaft  70  is coupled the internal quick connector wherein the milled upper end feature  72  of the splined shaft is coupled to, and rotatable with, the gear  63 . 
     After positioning, a user operator manually raises the second cutter  114  such that the connection portion  124  is received within the inner ring portion  95  of the ring shaped spindle  92  which has previously been positioned in an additional intermediate or raised position above the lowered position, where the user turns the set screw  97 , typically using an Allen wrench, to connect (i.e., reversibly couple) the inner ring portion  95  to the connection portion  124  of the second cutter  114 . While the second cutter  114  is being raised, the bottom end  76  of the splined shaft  70  is received within the second cutter such that the splines  74  are accepted within the internal surface  106  and intermeshed with the splined regions  108 . 
     In certain embodiments, as illustrated in  FIG.  9    and after coupling the second cutter  114  to the inner ring portion  95  in the raised position, the user/operator pivots the feed mechanism  80  (by actuating the pneumatic actuator  96 ) from the raised position to an additional intermediate position. In this additional intermediate position, the tip end  120  of the cutter  110 ,  114  is positioned within the secondary hole  210  while maintaining an intermediate length portion of the length of the splined shaft  70  including the splines  74  in engagement with the splined regions  108  of the internal surface  106  of the second cutter  110 ,  114 . 
     Next, as illustrated in  FIG.  10   , the user/operator provides power to generate a magnetic field to magnetically mount and secure the magnetic base  105  of the portable electric drilling assembly  20  to the working surface  30 . The user/operator actuates the electric motor  60  and the electric motor  60  (i.e., reactivates the motor  60 ) rotates about a drive axis and rotates the gear  63  contained within the gear housing  64 , which in turn rotates the splined shaft  70  quick connected to the gear  63  within the gear housing  64 . At the same time, the intermeshing of the splines  74  of the splined shaft  70  with the splined regions  108  of the internal surface  106  causes the attached cutter  110 ,  114  to rotate in response. Stated another way, the rotation of the splined shaft  70  directly drives the rotation of the attached cutter  110 ,  114 . 
     Next, the user/operator pivots the feed mechanism  80  (by actuating the pneumatic actuator  96 ) from the additional intermediate position (as shown in  FIG.  9   ) to a lowered position (as shown in  FIG.  10   ) with the motor  60  activated. The actuator of the pneumatic actuator causes the pinion gear  88  to rotate and move in a rectilinear movement away from the gear  63  along the rack  90  and towards the working surface  30  (downward as shown in  FIG.  10   ) while remaining intermeshed with the teeth  91  in the rack  90 . The rotation of the cutter  110 ,  114  during this movement from the intermediate position to the lowered position drills a tertiary hole  220  in the workpiece  32  of increasing depth in a direction away from the working surface  30  that is axially aligned with and beneath the pilot hole  200  and secondary hole  210  (as shown in  FIG.  10   ). In certain instances, as also shown in  FIG.  10   , the drilling results in the tertiary hole  220  breaking through the bottom surface of the workpiece  32 , therein forming a breakout opening  225 . 
     Once the drilling assembly  20  reaches the lowered position, as in  FIG.  10    and completes the drilling of the tertiary hole  220 , the user/operator pivots the feed mechanism  80  (by actuating the pneumatic actuator  96 ) back to the raised position, as shown in  FIG.  12   . The user/operator then turns off the electric motor  60  (i.e., deactivates the electric motor  60 ), and then turns off the magnetic base  105 , and optionally moves the drilling assembly  20  away from the drilled tertiary hole  220 . The splined shaft  70  is unconnected from the quick connect mechanism of the gear  63 , and the cutter  110 ,  114  can then be uncoupled from the spindle  92 . Any additional slug (not shown) may be removed from the tertiary hole  220  by the user/operator, or the slug may drop out through the breakout opening  225  if formed. 
     Notably, the difference in depth between the secondary hole  210  and the tertiary hole  220  beneath the working surface  30  corresponds to the difference in length between the first cutter  112  and the second cutter  114  (i.e., the difference between L 1 ′ and L 1 ″, with the assumption that the drilling device  20  has been moved to the lowered position in each respective drilling operation used to form the secondary hole  210  and tertiary hole  220 ). 
     While the process as illustrated in the exemplary embodiment of the operational method as illustrated in  FIGS.  3 - 10    is illustrated in which two different length cutters  112 ,  114  are used to drill the secondary hole  210 , the process is not limited to the use of two cutters  112 ,  114 . In particular, additional cutters  110  of longer lengths than the second cutter  114  may be used to increase the depth the secondary hole  210  and/or tertiary hole  220  beneath the working surface  30  as desired while repeating the process as described the method associated with  FIGS.  8 - 10    above. Still further, cutters  110  having lengths between the lengths of the first and second cutter  112 ,  114  may be used to drill hole having a depth between the illustrated secondary hole  210  and tertiary hole  220  as illustrated in the Figures herein. 
     Accordingly, the maximum depth of the secondary hole  210  and/or the tertiary hole  220  beneath the working surface  30 , as drilled by the series of cutters  110  as described in the method of  FIGS.  3 - 10   , is ultimately a function of the length of the longest respective cutter  110 ,  112 ,  114  utilized to drill the secondary hole  210 , with the maximum depth determined when the portable drilling assembly  20  is positioned in the lowered position. 
     Even still further, additional cutters  110  having larger cross-sectional diameters than the first cutter  112  and the second cutter  114  may be used to increase diameter the secondary hole  210  and/or tertiary hole  220  beneath the working surface  30  as desired while repeating the process as described the method associated with  FIGS.  8 - 10    above 
     In operations wherein the secondary hole  210  and/or the tertiary hole  220  of the workpiece  32  is required to have a reamed inner surface (corresponding to a desired final inner diameter), and in certain instances smoother reamed inner surface, than is provided by the cutter  110 ,  112 ,  114 , the operational method of the subject application may further include further one or two additional reaming steps utilizing the smaller and larger reamers  132  and  134 , as illustrated in  FIGS.  13 - 22    below. 
     Referring first to  FIGS.  13 A and  13 B , the operational method begins wherein a first reamer  130  (here shown as the smaller reamer  132 ) is positioned above the pilot hole  200  with the connection portion  124  of the reamer  132  received within the internal diameter of the spindle  92  and with the pivoting feed mechanism  80  positioned in the raised position wherein the spindle  92  is positioned in its closest proximity to the gear  63  and in its furthest proximity from the working surface  30  of the workpiece  32  and pilot hole  200 . In this position, the bottom end  140  of the reamer  130 ,  132 , is positioned adjacent to the opening defining the pilot hole  200  at the working surface  30 , and the user/operator inserts and tightens a set screw  97 , typically with an Allen wrench, to reversibly couple the reamer  130 ,  132  to the spindle  92  in the same manner as coupling the cutter  110 ,  112 ,  114  as described above. In addition, the splined shaft  70  is quick connected to the gear  63  via the quick connection mechanism  65  according to the procedure described above in  FIG.  3 A  and  FIG.  11   . 
     Next, the user/operator operates a control switch (not shown) to provide power to generate a magnetic field to magnetically mount and secure the magnetic base  105  of the portable electric drilling assembly  20  to the working surface  30 . The user/operator actuates the electric motor  60  (i.e., reactivates the motor  60 ) and the electric motor  60  rotates about a drive axis and rotates the gear  63  contained within the gear housing  64 , which in turn rotates the splined shaft  70  quick connected to the gear  63  within the gear housing  64 . At the same time, the intermeshing of the splines  74  of the splined shaft  70  with the splined regions  137  of the internal surface  136  causes the attached reamer  130 ,  132  to rotate in response. Stated another way, the rotation of the splined shaft  70  directly drives the rotation of the attached reamer  130 ,  132 . 
     Next, as shown in  FIGS.  14 A,  14 B and  15   , the user/operator pivots the feed mechanism  80  (by actuating the pneumatic actuator  96 ) from the raised position (as shown in  FIGS.  13 A and  13 B ) through an intermediate position (as shown in  FIGS.  14 A and  14 B ) to a lowered position (as shown in  FIG.  15   ). The actuation of the pneumatic actuator  96  causes the pinion gear  88  to rotate and move in a rectilinear movement away from the gear  63  along the rack  90  and towards the working surface  30  (downward as shown in  FIG.  14   ) while remaining intermeshed with the teeth  91  in the rack  90 . The rotation of the reamer  130 ,  132  during this movement from the raised position through the intermediate position to the lowered position reams the pilot hole  200  and the secondary hole  210  and possibly a portion of the tertiary hole  220  in the workpiece  32  to provide a reamed interior surface to form the reamed pilot hole  200 A and reamed secondary hole  210 A and reamed tertiary hole  220 A (see  FIG.  16   ). 
     Once the drilling assembly  20  reaches the lowered position, as in  FIG.  15    and completes the reaming of the secondary hole  210 A, the user/operator pivots the feed mechanism  80  (by actuating the pneumatic actuator  96 ) back to the raised position, as shown in  FIG.  16   . The user/operator then turns off the electric motor  60 , and then turns off the magnetic base  105 , and optionally moves the drilling assembly  20  away from the reamed pilot hole  200 A and reamed secondary hole  210 A and portion of the reamed tertiary hole  220 A, as shown in  FIG.  17   . The reamer  130 ,  132  can then be uncoupled from the spindle  92 , and the splined shaft  70  can be disconnected from the quick connect mechanism  65  of the gear  63 . 
     Next, also illustrated in  FIG.  17   , the user/operator can clean the work area on the working surface  30  surrounding the reamed pilot hole  200 A, reamed secondary hole  210 B and reamed tertiary hole  220 B and remove any debris and excess coolant. 
     In operations wherein the entirety of the tertiary hole  220  is desired to be reamed to the breakout opening  225 , the operational method of the subject application may further include a second reaming step, as illustrated in  FIGS.  18 - 22    below. The second reaming step follows similar operational steps to the second drilling step described above in  FIGS.  8 - 12   . 
     Referring now to  FIG.  18   , a second reamer  130 , here shown as the longer reamer  134 , is positioned within the tertiary hole  220  with the bottom end  120  seated at the bottom of the tertiary hole  220  and with the connection portion  124  exposed beneath the spindle  92 . 
     Next, as illustrated in  FIG.  19   , the user/operator pivots the feed mechanism  80  (by actuating the pneumatic actuator  96 ) from the raised position to an intermediate position. In this position, the connection portion  144  of the reamer  130 ,  134  is aligned and introduced within the interior of the spindle  92 , and the user/operator inserts and tightens a set screw (not shown) to couple the reamer  130 ,  134  to the spindle  92 . In addition, the user/operator raises the splined shaft  70  such that it can be quick connected to the gear  63  via the quick connection mechanism  65  in the same manner described above with respect to  FIG.  3 A  and  FIG.  11   . 
     Next, as illustrated in  FIG.  20   , the user/operator provides power to generate a magnetic field to magnetically mount and secure the magnetic base  105  of the portable electric drilling assembly  20  to the working surface  30 . The user/operator actuates the electric motor  60  and the electric motor  60  rotates about a drive axis and rotates the gear  63  contained within the gear housing  64 , which in turn rotates the splined shaft  70  quick connected to the gear  63  within the gear housing  64 . At the same time, the intermeshing of the splines  74  of the splined shaft  70  with the splined regions  137  of the internal surface  136  causes the attached reamer  130 ,  134  to rotate in response. Stated another way, the rotation of the splined shaft  70  directly drives the rotation of the attached reamer  130 ,  134 . 
     Next, the user/operator pivots the feed mechanism  80  (by actuating the pneumatic actuator  96 ) from the intermediate position (as shown in  FIG.  20   ) to a lowered position (as shown in  FIG.  21   ). The actuating of the pneumatic actuator  96  causes the pinion gear  88  to rotate and move in a rectilinear movement away from the gear  63  and towards the working surface  30  (downward as shown in  FIG.  10   ) while remaining intermeshed with the teeth  91  in the rack  90 . The rotation of the reamer  130 ,  134  during this movement from the intermediate position to the lowered position reams the entirety of the tertiary hole  220  in the workpiece  32  to the breakout opening  225 . The result is a hole having a twice reamed pilot hole  200 B, a twice reamed secondary hole  210 B interconnected and extending from the twice reamed pilot hole  200 B, and a once or twice reamed tertiary hole  220 B interconnected and extending from the twice reamed secondary hole  210 B. An optionally reamed breakout opening  225  is also provided in certain embodiments. 
     Once the drilling assembly  20  reaches the lowered position, as in  FIG.  20    and completes the reaming of the tertiary hole  220  to form the reamed tertiary hole  220 A, the user/operator pivots the feed mechanism  80  (by actuating the pneumatic actuator  96 ) back to the raised position, as shown in  FIG.  21   . The user/operator then turns off the electric motor  60 , and then turns off the magnetic base  105 , and optionally moves the drilling assembly  20  away from the drilled tertiary hole  220 . The splined shaft  70  is unconnected from the quick connect mechanism of the gear  63 , and then the reamer  130 ,  134  can then be uncoupled from the spindle  92 . A cleaning operation, similar to that provided in  FIG.  17    can then be performed to remove any debris or coolant from the working surface  30  surrounding the drilled and reamed openings. 
       FIGS.  24 - 26    illustrate an operational method for utilizing the portable electric drilling assembly  20  in accordance with another embodiment in which the handle  250  replaces the pneumatic system illustrated in  FIGS.  1 ,  3 - 10 , and  12 - 23    (including the pneumatic actuator  96  and the associated components) to drill and subsequently ream a hole into the working surface  30  of a workpiece  32  utilizing the two cutters  112 ,  114  and two reamers  132 ,  134  of the subject application. Similar to the prior embodiment, the operations of the portable electric drilling assembly  20  of  FIGS.  24 - 26    are ideally suited for drilling such holes in workpiece  32  within a confined space  50 , although the operation of the drilling assembly  20  in accordance with the description of  FIGS.  24 - 26    can also be performed on workpieces not in a confined space. The operational method for utilizing the portable electric drilling assembly  20  in accordance with the embodiment in  FIGS.  24 - 26    is very similar to the operational method of the pneumatic system illustrated in  FIGS.  1 ,  3 - 10 , and  12 - 23   , but simply includes where the handle  250  is pivoted, as compared with the pneumatic system illustrated in  FIGS.  1 ,  3 - 10 , and  12 - 23   , to achieve the same drilling and reaming result. For ease of description and illustration, movement between a raised position ( FIG.  24   ) and a lowered position ( FIG.  25   ) is described, but similar to the embodiment in  FIGS.  1 ,  3 - 10 , and  12 - 23    a plurality of intermediate positions between the raised and lowered positions are contemplated. 
     In general, during this operational method and similar to the operation method associated with the embodiment of  FIGS.  1 ,  3 - 10  and  12 - 23    above, when the workpiece  32  is a metal workpiece, the portable electric drilling assembly  20  is disposed on the working surface  30 , such as wherein the workpiece  32  is situated in the confined space  50 . The user/operator operates a control switch (not shown) to provide power to generate a magnetic field to magnetically mount and secure the magnetic base  105  of the portable electric drilling assembly  20  to the working surface  30 . The user/operator actuates the electric motor  60  and the electric motor  60  rotates about a drive axis and rotates the gear  63  contained within the gear housing  64 , which in turn rotates the splined shaft  70  quick connected to the gear  63  within the gear housing  64 . At the same time, the intermeshing of the splines  74  of the splined shaft  70  with the splined regions  108  of the internal surface  106  causes the attached cutter  110 ,  112 ,  114  (or the intermeshing of the splines  74  of the splined shaft  70  with the splined regions  137  of the internal surface  136  of the attached reamer  130 ,  132 ,  134 ) to rotate in response and drill or ream the hole to a desired cross-sectional diameter. Still further, by pivoting the handle  250  of the feed mechanism from a raised position to an intermediate or lowered position, the depth of the drill or ream the hole can be precisely controlled, with the maximum depth corresponding to the stroke length associated with the pivoting the handle of the feed mechanism  80  from a raised position to the lowered position as described further below. 
     Referring first to  FIG.  24   , the operational method begins wherein a first cutter  110  (here shown as the smaller cutter  112 ) is positioned above a pilot hole  200  with the connection portion  124  of the cutter  112  received within the internal diameter of the spindle  92  and with the handle  250  of the feed mechanism  80  positioned in the raised position wherein the spindle  92  and handle  250  are positioned in its closest proximity to the gear  63  and in its furthest proximity from the working surface  30  of the workpiece  32  and pilot hole  200 . The pilot hole  200  has been predrilled into the working surface  30  and provides an orientation for guide for the drilling of the hole as provided in the operational method. In this position, the bottom end  120  of the cutter  110 ,  112 , is positioned adjacent to the opening defining the pilot hole  200  at the working surface  30 , and the user/operator inserts and tightens the set screw  97 , typically with an Allen wrench, to couple the connection portion  124  of the cutter  110 ,  112  to the inner ring portion  95  of the spindle  92 . 
     In addition, the splined shaft  70  is quick connected to the gear  63  via the quick connection mechanism  65 , as best shown in  FIG.  11   . In particular, the splined shaft  70  is first aligned with and positioned beneath the gear  63  of the quick connect mechanism  65  by the user/operator, as shown in  FIG.  11 A . Next, as shown in  FIG.  11 B , the user/operator inserts the turned and milled upper end feature  72  of the splined shaft  70  within the quick connect mechanism. Finally, the splined shaft  70  is rotated a quarter turn in the opposite direction of the twisted flutes  118 , thereby coupling the turned and milled upper end feature  72  with the gear  63 , which allows the splined shaft  70  to rotate as the gear  63  rotates. 
     Next, the user/operator operates a control switch (not shown) to provide power to generate a magnetic field to magnetically mount and secure the magnetic base  105  of the portable electric drilling assembly  20  to the working surface  30 . The user/operator actuates the electric motor  60  and the electric motor  60  rotates about a drive axis and rotates the gear  63  contained within the gear housing  64 , which in turn rotates the splined shaft  70  quick connected to the gear  63  within the gear housing  64 . At the same time, the intermeshing of the splines  74  of the splined shaft  70  with the splined regions  108  of the internal surface  106  causes the attached cutter  110 ,  112  (and inner ring portion  95  within the fixed outer portion  93  of the spindle  92 ) to rotate in response. Stated another way, the rotation of the splined shaft  70  directly drives the rotation of the attached cutter  110 ,  112 . 
     Next, as shown in  FIG.  25   , the user/operator moves the feed mechanism  80  (by applying force in a downward direction as shown in  FIGS.  24 - 26    to pivot the handle  250 ) from the raised position (as shown in  FIG.  24   ) to an intermediate position with the ratchet mechanism in the second ratchet position (the first ratchet position is shown in  FIG.  25   ). The force applied to the handle  250  downward pivots the handle  250  and causes the coupled pinion gear  88  to rotate and move in a rectilinear movement away from the gear  63  and towards the working surface  30  (downward as shown moving  FIG.  24    to  FIG.  25   ) while remaining intermeshed with the teeth  91  in the rack  90 . The rotation of the cutter  110 ,  112  (caused by the rotation of the coupled splined shaft  70  and gear  63  rotated by the motor  60 ) during this movement from the raised position through the intermediate position to the lowered position drills a secondary hole  210  in the workpiece  32  of increasing depth in a direction away from the working surface  30  that is axially aligned with the pilot hole  200  to drill the secondary hole  210 . In other words, the relative amount of movement of the feed mechanism  80 , and in particular the handle  250 , from the raised position (as shown in  FIG.  24   ) through an intermediate position (as shown in  FIG.  25   ) controls the relative depth of the secondary hole  210  drilled. 
     The depth of the secondary hole  210  beneath the pilot hole  200  is a function of a stroke length of the drilling assembly  20  with the attached cutter  110 ,  112  moved to the lowered position. In particular, the stroke length is defined as the length of movement of the spindle  92  between any two operating positions between and including the raised and lowered positions and may be determined by subtracting the height of the spindle  92  relative to the working surface  30  in a second operating position from the height of the spindle  92  relative to the working surface  30  in a first operating position, with the second operating position of the spindle  92  being closer to the working surface  30  than the first operating position of the spindle  92 . 
     The maximum depth of the secondary hole  210  beneath the pilot hole  200 , which is shown in  FIG.  25   , may be defined in terms of the maximum stroke length  300  of the drilling assembly  20  that is calculated by subtracting the gearbox height  305 , the spindle height  310  and the chip clearance height  315  from the machine height  320  in the lowered position. In this calculation, the machine height  320  is fixed and is defined as the distance between the top of the gear box housing  64  and the working surface. Similarly, the gearbox height  305  is also fixed, and is defined as the distance between the top of the gear box housing and the bottom of the gear box housing  64  associated with portion of the gear box  62  including the quick connection mechanism  65 . The spindle height  310  is further defined as the distance between the upper and lower surface of the spindle  92 , while the chip clearance height  315  is further defined as the distance between the bottom of the spindle  92  and the working surface  30  of the workpiece  32  in the lowered position. 
     Once the drilling assembly  20  reaches the lowered position, as in  FIG.  26    and completes the drilling of the secondary hole  210  and corresponding to the maximum stroke  300  in circumstances where the drilling assembly began in the raised position, the user/operator moves the rachet mechanism  239  to the first ratchet position (as shown in each of  FIGS.  24 - 26   ) and moves the feed mechanism  80  (by applying force upward on the handle  250 ) back to the raised position, as shown in  FIG.  24   . The user/operator then turns off the electric motor  60 , and then turns off the magnetic base  105  and turns of the electric motor  60  and moves the drilling assembly  20  away from the drilled secondary hole  210  from the lowered position to the raised position. The cutter  110 ,  112  can then be uncoupled from inner ring portion  95  of the spindle  92  by turning the set screw  97 , typically using an Allen wrench, such that it is out of contact with the connection portion  124  of the first cutter  112 , and the splined shaft  70  may optionally be unconnected from the quick connect mechanism of the gear  63 . The first cutter  112  can then be removed from the secondary hole  210 . 
     The operational method in accordance with the alternative embodiment illustrated in  FIGS.  24 - 26    can also be used to subsequently drill the tertiary hole  220 , and to subsequently ream the drilled hole  200 ,  210 ,  220  to form a reamed hole  200 A,  210 A,  220 A, in substantially the same manner as described in the embodiment of  FIGS.  1 ,  3 - 10 , and  12 - 23    corresponding to the steps described above corresponding to  FIGS.  6 - 10  and  12 - 23    and are not repeated herein for the sake of brevity, and the only distinctions between the operational methods are in terms of replacing the pivoting movement of the pneumatics including the pneumatic actuator  96  in  FIGS.  6 - 10  and  12 - 23    with the movement of the handle  250  upward and downward between the raised and lowered position (i.e., the coupling/uncoupling of the second cutters  114  or the reamers  130 ,  132 ,  134  to the spindle  92  and the actual process whereby they respectively drill a secondary hole  210  or tertiary hole  220  and/or subsequently ream the holes  200 ,  210 ,  220  to form reamed holes  200 A,  210 A,  220 A is the same in each embodiment. 
       FIGS.  27 - 29    illustrate an operational method for utilizing the portable electric drilling assembly  20  in accordance with another embodiment in which an electric feed mechanism  280  replaces the feed mechanism  80  including the pneumatic system illustrated in  FIGS.  1 ,  3 - 10 , and  12 - 23    (including the pneumatic actuator  96  and the associated components) to drill and subsequently ream a hole into the working surface  30  of a workpiece  32  utilizing the two cutters  112 ,  114  and two reamers  132 ,  134  of the subject application. Similar to the prior embodiment, the operations of the portable electric drilling assembly  20  of  FIGS.  1 ,  3 - 10 , and  12 - 23    and separately of  FIGS.  24 - 26    are ideally suited for drilling such holes in workpiece  32  within a confined space  50 , although the operation of the drilling assembly  20  in accordance with the description of  FIGS.  27 - 29    can also be performed on workpieces not in a confined space. The operational method for utilizing the portable electric drilling assembly  20  in accordance with the embodiment in  FIGS.  27 - 29    is very similar to the operational method of the pneumatic system illustrated in  FIGS.  1 ,  3 - 10 , and  12 - 23   , and the handle  250  of  FIGS.  24 - 26   , but simply includes where the electric feed mechanism  280  replaces a portion of the components in the pneumatic system illustrated in  FIGS.  1 ,  3 - 10 , and  12 - 23    and is actuated to rotate the pinion gear  88  to achieve the same drilling and reaming result as in the embodiments of  FIGS.  1 ,  3 - 10   , and  12 - 23  and  FIGS.  24 - 26    described above. For ease of description and illustration, movement between a raised position ( FIG.  27   ), a single intermediate position ( FIG.  28   ) and a lowered position ( FIG.  29   ) is described, but similar to the embodiment in  FIGS.  1 ,  3 - 10 , and  12 - 23    and the embodiment in  FIGS.  24 - 26   , a plurality of intermediate positions between the raised and lowered positions are contemplated. 
     In general, the electric feed mechanism  280  having a mechanism housing  282  pivotally coupled to the gear box housing  64  with a fastening mechanism  284 , here shown as a pin  284  contained within a slot  286  defined by the mechanism housing  282 . The feed mechanism  280  includes the pinion gear  88  rotatably coupled and engaged to the rack  90 . The drilling assembly  20  also includes the spindle  92 , preferably the ring-shaped spindle  92  having an outer fixed portion  93 , coupled to an end  295  of the mechanism housing  282  generally adjacent to the pinion gear  88 . The spindle  92  also includes the inner ring portion  95  contained within the outer fixed portion  93  which is rotatable relative to the outer fixed portion  95 . In particular, the pinion gear  88  is engaged (i.e., intermeshed) with the teeth  91  of the rack  90  and moves along the rack  90  as it rotates to achieve rectilinear movement of both the pinion gear  88  and the spindle  92  (i.e., up and down movement as illustrated in the Figures) during a drilling operation similar to the mechanism describe in each of the embodiments illustrated in  FIGS.  1 ,  3 - 10 , and  12 - 23  and  24 - 26   , respectively. 
     The electric feed mechanism  280  also includes a power feed control box  290  that an electrical connector  292  for coupling to an electrical power source (not shown), an electrical switch  294  including an up button  296  and a down button  298 , an upper limit switch  300 , a lower limit switch  302 , and an electric motor (now shown) which is electrically coupled to the electrical switch and which is mechanically coupled to the plurality of feed gears, including the feed gear  98 , contained within the mechanism housing  282 . 
     In general, during this operational method and similar to the operation method associated with the embodiment of  FIGS.  1 ,  3 - 10  and  12 - 23    and the embodiment of  FIGS.  24 - 26    above, when the workpiece  32  is a metal workpiece, the portable electric drilling assembly  20  is disposed on the working surface  30 , such as wherein the workpiece  32  is situated in the confined space  50 . The user/operator operates a control switch (not shown) to provide power to generate a magnetic field to magnetically mount and secure the magnetic base  105  of the portable electric drilling assembly  20  to the working surface  30 . The user/operator actuates the electric motor  60  and the electric motor  60  rotates about a drive axis and rotates the gear  63  contained within the gear housing  64 , which in turn rotates the splined shaft  70  quick connected to the gear  63  within the gear housing  64 . At the same time, the intermeshing of the splines  74  of the splined shaft  70  with the splined regions  108  of the internal surface  106  causes the attached cutter  110 ,  112 ,  114  (or the intermeshing of the splines  74  of the splined shaft  70  with the splined regions  137  of the internal surface  136  of the attached reamer  130 ,  132 ,  134 ) to rotate in response and drill or ream the hole to a desired cross-sectional diameter. Still further, the user actuates the electric feed mechanism  280  to move the portable drill assembly  20  from a raised position to an intermediate or lowered position, the depth of the drill or ream the hole can be precisely controlled, with the maximum depth corresponding to the stroke length associated with the length of the movement of the spindle  92  from a raised position to the lowered position as described further below. 
     Referring first to  FIG.  27   , the operational method begins wherein a first cutter  110  (here shown as the smaller cutter  112 ) is positioned above a pilot hole  200  with the connection portion  124  of the cutter  112  received within the internal diameter of the spindle  92  and with the pivoting feed mechanism  80  positioned in the raised position wherein the spindle  92  is positioned in its closest proximity to the gear  63  and in its furthest proximity from the working surface  30  of the workpiece  32  and pilot hole  200 . The pilot hole  200  has been predrilled into the working surface  30  and provides an orientation for guide for the drilling of the hole as provided in the operational method. In this position, the bottom end  120  of the cutter  110 ,  112 , is positioned adjacent to the opening defining the pilot hole  200  at the working surface  30 , and the user/operator inserts and tightens the set screw  97  (see  FIGS.  11 A-C ), typically with an Allen wrench, to reversibly couple the connection portion  124  of the cutter  110 ,  112  to the inner ring portion  95  of the spindle  92 . As one of skill appreciates, by loosening the set screw  97 , the process of coupling the connection portion  124  of the cutter  110 ,  112  to the inner ring portion  95  of the spindle  92  can be reversed. 
     In addition, the splined shaft  70  is quick connected to the gear  63  via the quick connection mechanism  65 , as also best shown in  FIGS.  11 A- 11 C . In particular, the splined shaft  70  is first aligned with and positioned beneath the gear  63  which includes a quick connect mechanism  65  by the user/operator, as shown in  FIG.  11 A , by twisting the splined shaft  70  in a clockwise or counterclockwise direction until the splines  74  of the splined shaft  70  are aligned with the internal opening  63 A within the gear  63  and with the inwardly extending recessed portion  73  not including the ledge  77  aligned beneath the steel pin  67 . Next, as shown in  FIG.  11 B , the user/operator inserts the turned and milled upper end feature  72  of the splined shaft  70  within the internal opening  63 A of the gear  63  by moving the splined shaft  70  towards the gear  63  (shown by arrow  71 ) such that the turned and milled upper end feature  72  of the splined shaft  70  is contained within the internal opening  63 A within the gear  63 . Finally, the splined shaft  70  is rotated a quarter turn (shown by arrow  81 ), thereby positioning the ledge  77  adjacent to and above the quick connect feature  65  (i.e., above the steel pin  67 ). In this position, the splined shaft  70  cannot be pulled in a direction away from the gear  63  and gear housing  64  towards the working surface  30  because the ledge  77  is prevented from moving by the quick connect mechanism  65 , here the steel pin  67 . In the connected position, the gear  63  is engaged with the splined shaft  70 , and hence the splined shaft  70  rotates as the plurality of gears  63  are rotated. 
     To disconnect the splined shaft  70  from the quick connect feature  65  and remove the splined shaft  70  from engagement with the gear  63 , the user rotates the splined shaft  70  a quarter turn in the opposite direction of arrow  81 , at which point the inwardly extending recessed portion  73  is aligned with the steel pin  67  but wherein the ledge  77  is not above the steel pin  67  of the quick connect feature  65 , which allows the user/operator to move the splined shaft  70  away from the gear box  64  towards the working surface  30  (i.e., in an opposite direction to arrow  71  shown in  FIG.  11 B ) to the unconnected position as shown in  FIG.  11 A . 
     Referring back to  FIG.  27   , and while not illustrated specifically in these figures, it is understood that a maximum length of the splined shaft  70  (hidden within the cutter  110 ,  112  as illustrated) is received within the component cavity defined by the internal surface  106  of the cutter  110 ,  112 . 
     Next, the user/operator operates a control switch (not shown) to provide power to generate a magnetic field to magnetically mount and secure the magnetic base  105  of the portable electric drilling assembly  20  to the working surface  30 . The user/operator actuates the electric motor  60  and the electric motor  60  rotates about a drive axis and rotates the gear  63  contained within the gear housing  64 , which in turn rotates the splined shaft  70  quick connected to the gear  63  within the gear housing  64 . At the same time, the intermeshing of the splines  74  of the splined shaft  70  with the splined regions  108  of the internal surface  106  causes the attached cutter  110 ,  112  (and inner ring portion  95  contained within the fixed outer portion  93  of the spindle  92 ) to rotate in response. Stated another way, the rotation of the splined shaft  70  directly drives the rotation of the attached cutter  110 ,  112  which drives the rotation of the inner ring portion  95 . 
     Next, as shown in  FIG.  27 - 29   , the user/operator actuates the electrical switch  294 , here depressing the down switch  298 , which results in the pivoting of the electric feed mechanism  280  and movement of the spindle  92  from the raised position (as shown in  FIG.  27   ) through an intermediate position (as shown in  FIG.  28   ) to a lowered position (as shown in  FIG.  5   ). The actuation of the electrical switch  294 , here the depression of the down switch  298 , causes the feed gears  98  and the coupled pinion gear  88  to rotate, which causes the pinion gear  88  to move in a rectilinear movement away from the gear  63  and towards the working surface  30  (downward as shown in  FIGS.  28  and  29    relative to  FIG.  27   ) while remaining intermeshed with the teeth  91  in the rack  90 . The rotation of the cutter  110 ,  112  (caused by the rotation of the coupled splined shaft  70  and gear  63  rotated by the motor  60 ) during this movement from the raised position through the intermediate position to the lowered position drills a secondary hole  210  in the workpiece  32  of increasing depth in a direction away from the working surface  30  that is axially aligned with the pilot hole  200  (as best shown in  FIGS.  28  and  29   ). In other words, the relative amount of pivoting of the electric feed mechanism  280  from the raised position (as shown in  FIG.  27   ) through an intermediate position (as shown in  FIG.  28   ) to a lowered position (as shown in  FIG.  29   ) controls the relative depth of the secondary hole  210  drilled. 
     The depth of the secondary hole  210  beneath the pilot hole  200  is a function of a stroke length of the drilling assembly  20  with the attached cutter  110 ,  112  pivoted to the lowered position. In particular, the stroke length is defined as the length of movement of the spindle  92  between any two operating positions between and including the raised and lowered positions and may be determined by subtracting the height of the spindle  92  relative to the working surface  30  in a second operating position from the height of the spindle  92  relative to the working surface  30  in a first operating position, with the second operating position of the spindle  92  being closer to the working surface  30  than the first operating position of the spindle  92 . 
     The maximum depth of the secondary hole  210  beneath the pilot hole  200 , which is shown in  FIG.  29   , may be defined in terms of the maximum stroke length  300  of the drilling assembly  20  that is calculated by subtracting the gearbox height  305 , the spindle height  310  and the chip clearance height  315  from the machine height  320  in the lowered position. In this calculation, the machine height  320  is fixed and is defined as the distance between the top of the gear box housing  64  and the working surface. Similarly, the gearbox height  305  is also fixed, and is defined as the distance between the top of the gear box housing and the bottom of the gear box housing  64  associated with portion of the gear box  62  including the quick connection mechanism  65 . The spindle height  310  is further defined as the distance between the upper and lower surface of the spindle  92 , while the chip clearance height  315  is further defined as the distance between the bottom of the spindle  92  and the working surface  30  of the workpiece  32  in the lowered position. In this exemplary embodiment, the upper limit switch  300  and lower limit switch  302  function to limit the amount the electrical feed mechanism  280  can pivot, and thus can separately be used to define the maximum depth of the secondary hole  210  according to the calculations above. 
     As also shown in  FIG.  29   , the positioning of the electric feed mechanism  280  in the lowered position is such wherein a minimum length of the splined shaft  70  is received within the component cavity defined by the internal surface  106  of the cutter  110 ,  112 , but wherein this minimum length still results in the engagement of the splines  74  of the splined shaft  70  with the corresponding splined regions  108  of the internal surface  106  of the cutter  110 ,  112 , and thus the rotation of the splined shaft  70  results in the rotation of the attached cutter  110 ,  112  as described above. 
     Once the drilling assembly  20  reaches the lowered position, as in  FIG.  29    and completes the drilling of the secondary hole  210  and corresponding to the maximum stroke  300  in circumstances where the drilling assembly began in the raised position, the user/operator pivots the electric feed mechanism  280  by depressing the up button  296  back to the raised position, as shown in  FIG.  27   . The user/operator then turns off the electric motor  60  and then turns off the magnetic base  105  and moves the drilling assembly  20  away from the drilled secondary hole  210  from the lowered position to the raised position. The cutter  110 ,  112  can then be uncoupled (i.e., decoupled) from inner ring portion  95  of the spindle  92  by turning the set screw  97 , typically using an Allen wrench, such that it is out of contact with the connection portion  124  of the first cutter  112 , and the splined shaft  70  may optionally be unconnected from the quick connect mechanism of the gear  63 . The first cutter  112  can then be removed from the secondary hole  210 . 
     The operational method in accordance with the alternative embodiment illustrated in  FIGS.  27 - 29    can also be used to subsequently drill the tertiary hole  220 , and to subsequently ream the drilled hole  200 ,  210 ,  220  to form a reamed hole  200 A,  210 A,  220 A, in substantially the same manner as described in the embodiment of  FIGS.  1 ,  3 - 10 , and  12 - 23    corresponding to the steps described above corresponding to  FIGS.  6 - 10  and  12 - 23    and are not repeated herein for the sake of brevity, and the only distinctions between the operational methods are in terms of replacing the pivoting movement of the pneumatics including the pneumatic actuator  96  in  FIGS.  6 - 10  and  12 - 23    with the pressing of the up button  284  or down button  282  to pivot the electric feed mechanism between the raised and lowered position (i.e., the coupling/uncoupling of the second cutters  114  or the reamers  130 ,  132 ,  134  to the spindle  92  and the actual process whereby they respectively drill a secondary hole  210  or tertiary hole  220  and/or subsequently ream the holes  200 ,  210 ,  220  to form reamed holes  200 A,  210 A,  220 A is the same in each embodiment. 
     The subject application thus provides a solution for deep hole drilling processes for use in applications that also may have confined spaces to perform such drilling processes. By allowing for the separate connection of the splined shaft  70  and the cutter  110  or reamer  130  to form a cutter-spline drive prior to the operation of the portable electrical drilling assembly  20 , the drilling assembly  20  footprint can be reduced as compared with conventional COTS for use in confined spaces and provides for a method for drilling deep holes having a reduced number of steps necessary to achieve a desired final hole dimensional requirements. 
     The portable electrical drilling assembly  20  allows for the use of different length and dimensioned cutters  110  and reamers  130  for use with a common splined shaft  70  as a part of the cutter-spline drive that therefore allow the assembly  20  to easily drill and ream holes of varying depths and inner radial dimensions without increasing the footprint of portable electrical drilling assembly  20  between its raised and lowered positions. 
     The subject application is also directed to the use of the cutter-spline drive including the combination of the splined shaft  70  and cutters  110  or reamers  130  in other drilling assemblies other than portable electrical drilling assembly  20  described above. In these applications, and similar to the description above, the rotation of the splined shaft  70 , coupled within the internal surface  116 ,  136  of the respective cutter  110  or reamer  130 , drives the rotation of the respective cutter  110  or reamer  130  to drill or ream a hole within the working surface  30  of the workpiece  32 . 
     Still further, the subject application is also directed solely to the cutters  110  and reamers  130  for use in drilling assemblies that may include an associated splined shaft for driving the rotation of the cutters or reamers to drill or ream a hole in the within the working surface  30  of the workpiece  32 . 
     As one appreciates, secondary or tertiary holes  210 ,  220  can be drilled and reamed with varying depths and varying diameters in the workpiece  32  utilizing the portable drilling assembly  20  of the present disclosure, in accordance with the method described in  FIGS.  3 - 10  and  15 - 22    and alternatively in  FIGS.  24 - 25    above, without having to adjust the machine height  320  of the drilling assembly  20  above the working surface  30  of the workpiece  32  and while maintaining the same maximum stroke  300  for the drilling assembly  20  between the raised and lowered position. The drilling assembly  20  and associated method of use with the cutters  110  and reamers  130  provided herein is therefore particularly advantageous for use in drilling and reaming operations in which there is limited clearance in the area surrounding the drilling assembly  20  and workpiece  32  as defined by the walls  40  and roof  45  or the other encumbrances in proximity to the workpiece  32 . 
     While the disclosure has been described with reference to the examples above, it will be understood by those skilled in the art that various changes may be made, and equivalents may be substituted for elements thereof, without departing from the scope of the disclosure. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the disclosure without departing from the essential scope thereof. Therefore, it is intended that the disclosure not be limited to the particular embodiments disclosed as the best mode contemplated for carrying out this disclosure, but that the disclosure will include all examples falling within the scope of the appended claims.