Patent Publication Number: US-2023139793-A1

Title: System And Method For Forming Aligned Holes In A Work Piece

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of co-pending U.S. Pat. Application Serial No. 17/035,376, filed on Sep. 28, 2020 by the same inventor, which is a continuation-in-part of U.S. Pat. Application Serial No. 16/167,367, filed on Oct. 22, 2018 by the same inventor, both of which are incorporated herein by reference in their respective entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     This invention relates generally to drill jigs, and more particularly to a jig facilitating the linear alignment and relative spacing between drill holes. 
     Description of the Background Art 
     In construction and manufacturing industry, it is often desirable to drill multiple holes in a workpiece. Oftentimes, the workpiece specifications require holes to be drilled a particular distance from a previously drilled hole. One way this is accomplished is by using a drill stencil, which is essentially a rigid plate having a plurality of holes with fixed spacing therebetween. Before the drilling process, a user positions the stencil on the workpiece by some suitable means (e.g., tape, adhesive, clamp, etc.). With the stencil fixed to the workpiece, the user drills the areas of the workpiece exposed by the holes in the stencil. 
     There are several challenges inherent to the use of drilling stencils. As one example, such stencils wear out relatively quickly because they are typically made from materials softer than a drill bit, so as not to dull the drill bit. As the drill bit or bit guide contacts the stencil, it gradually wears on the stencil edges defining the holes. After so many uses, the stencil holes become so large and irregularly shaped that they no longer provide sufficient accuracy and/or precision. Of course, when this occurs, the stencil must be replaced. As another example, drill stencils provide for a very low degree of accuracy and precision even when they are new and unworn. This is because the stencil only exposes the part of the workpiece and does facilitate the perpendicular or angled positioning of the drill bit with respect to the workpiece. Consequently, the bore angles of the drill holes in the workpiece are often incorrect when a stencil is used. As yet another example, drilling multiple holes in a workpiece using a stencil is relatively time consuming, because it is difficult to achieve a high degree of accuracy and precision. 
     What is needed, therefore, is a device for drilling multiple holes in a workpiece that does not wear out. What is also needed is a device for drilling multiple holes in a workpiece with a higher degree of accuracy, precision, and/or consistency. What is also needed is a device for drilling multiple holes in a workpiece in much less time and with much less effort. 
     SUMMARY 
     The present invention overcomes the problems associated with the prior art by providing drill jigs for drilling precision spaced holes in a workpiece. Example embodiments of the invention facilitate quick and easy drilling of holes in a work piece, while reducing wear on the jig and providing better ergonomics for the user. 
     An example drill jig includes an edge alignment guide, a hole spacing assembly, a second guide, a first biasing member, and an actuator. The edge alignment is guide configured to abut an edge of a workpiece, to facilitate movement of the workpiece along a first straight line. The hole-spacing assembly includes a protrusion disposed to engage a preexisting hole in a workpiece positioned by the edge alignment guide. The second guide is coupled to the hole-spacing assembly and is configured to facilitate movement of the hole-spacing assembly along a second straight line perpendicular to the first straight line, whereby the protrusion can be moved into and out of the preexisting hole. The first biasing member is coupled to the hole-spacing assembly and is operative to exert a force on the hole-spacing assembly in a direction parallel to the second straight line. The actuator, responsive to a force applied by a component of a drill, is operative to move the hole-spacing assembly along the second straight line via the first biasing member. 
     A particular example embodiment additionally includes a base and a second biasing member. The base configured to be mounted on a drill press table, and the second guide is coupled to the base. The second biasing member is disposed between the hole-spacing assembly and the base. The stiffness of the first biasing member is greater than the stiffness of the second biasing member, so the second biasing member compresses before the first biasing member when the actuator is urged toward the base. The second guide can include a set (1 or more) of parallel rods fixed to the base, and the hole-spacing assembly is slidably coupled to the set of parallel rods. 
     In a particular example embodiment, the hole-spacing assembly includes a rigid body, and a position of the protrusion with respect to the rigid body is adjustable. For example, the rigid body can define a plurality of linearly aligned apertures, each aperture configured to selectively seat the protrusion. As another example, the rigid body can define a linear slot configured to adjustably seat the protrusion. In addition, the distance between the edge alignment guide and the protrusion can be adjustable. 
     The rigid body of the hole-spacing assembly defines an aperture through which a drill bit can pass when the first biasing member is compressed. The aperture also facilitates the alignment of the rigid body with respect to the drill bit during the mounting of the base to a drill press table. Optionally, the aperture can be replaced with a notch or channel to facilitate the passage of the drill bit and alignment of the base with respect to the drill press table. 
     The rigid body of the hole-spacing assembly can transparent. The rigid body can also include indicia (e.g., rule markings, measuring scale, etc.) configured to identify the position of the alignment protrusion with respect to the rigid body. As another option, the protrusion can define a tapered end configured to engage a drill hole. The tapered end can be smooth to prevent any damage to the drill hole. 
     In another example drill jig, the hole-spacing assembly includes a rigid body, and the edge alignment guide is an integral feature defined by the rigid body. A position of the protrusion with respect to the rigid body can be adjustable, and the rigid body can be transparent. 
     Another example drill jig includes a rigid body and a protrusion coupled to the rigid body. The rigid body includes an edge alignment guide and a drill attachment feature. The edge alignment guide is configured to abut an edge of a workpiece to facilitate movement of the rigid body along a straight line parallel to the edge of the workpiece. The drill attachment feature is configured to facilitate the mounting of the rigid body to a drill component. A protrusion is coupled to the rigid body and is configured to engage a preexisting hole in a workpiece positioned by the edge alignment guide. The protrusion can be adjustably coupled to the rigid body, whereby a position of the protrusion with respect to the rigid body can be changed. Optionally, the rigid body can be transparent. 
     Methods for manufacturing a drill jig are also disclosed. One example method includes providing an edge alignment guide configured to abut an edge of a workpiece to facilitate movement of the workpiece along a first straight line. The example method additionally includes providing a hole-spacing assembly including a protrusion disposed to engage a preexisting hole in a workpiece positioned by the edge alignment guide, and providing a second guide configured to facilitate movement of the hole-spacing assembly along a second straight line perpendicular to the first straight line. The method additionally includes coupling the second guide to the hole-spacing assembly, providing a biasing member, and coupling the biasing member to the hole-spacing assembly, so that the biasing member is operative to exert a force on the hole-spacing assembly in a direction parallel to the second straight line. The method additionally includes providing an actuator and coupling the actuator to the biasing member so that, responsive to a force applied by a component of a drill, the actuator is operative to move the hole-spacing assembly along the second straight line via the biasing member. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention is described with reference to the following drawings, wherein like reference numbers denote substantially similar elements: 
         FIG.  1    is a perspective view of an example drill jig; 
         FIG.  2    is an exploded perspective view of the drill jig of  FIG.  1   ; 
         FIG.  3    is an exploded perspective view of an actuator of the drill jig of  FIG.  1   ; 
         FIG.  4    is an exploded perspective view of a hole-spacing assembly of the drill jig of  FIG.  1    ; 
         FIG.  5    is an exploded perspective view of a base and guides of the drill jig of  FIG.  1   ; 
         FIG.  6 A  is a front view of the drill jig of  FIG.  1    during the initial coupling of the drill jig to a drill press; 
         FIG.  6 B  is a front view of the drill jig of  FIG.  1    coupled to a drill press in a non-actuated position; 
         FIG.  6 C  is a front view of the drill jig of  FIG.  1    coupled to a drill press in a semi-actuated position; 
         FIG.  6 D  is a front view of the drill jig of  FIG.  1    coupled to a drill press in an actuated position; 
         FIG.  7    is an exploded perspective view of an alternate hole-spacing assembly; 
         FIG.  8    is an exploded perspective view of another alternate hole-spacing assembly; 
         FIG.  9    is a cross-sectional view of the hole-spacing assembly of  FIG.  8   ; 
         FIG.  10    is a perspective view of an example drill attachment; 
         FIG.  11    is a front view of the drill attachment of  FIG.  10    mounted on a portable drill press; 
         FIG.  12    is a flowchart summarizing an example method of manufacturing a drill jig; 
         FIG.  13    is a perspective view of another example drill jig; 
         FIG.  14    is an exploded perspective view of the drill jig of  FIG.  13   ; 
         FIG.  15    is an exploded perspective view of the actuator of  FIG.  13   ; 
         FIG.  16    is a rear perspective view of the body of the actuator of  FIG.  13   ; 
         FIG.  17    is a perspective view of the hole-spacing assembly of the drill jig of  FIG.  13   ; 
         FIG.  18    is a side view of the body of the hole-spacing assembly of  FIG.  17   ; 
         FIG.  19 A  is a top view of the hole-spacing assembly of  FIG.  17    in a first configuration; 
         FIG.  19 B  is a top view of the hole-spacing assembly of  FIG.  17    in a second configuration; 
         FIG.  20    is a perspective view of another example drill jig; 
         FIG.  21    is a rear perspective view of the body of the actuator of  FIG.  20   ; 
         FIG.  22    is a rear perspective view of the body of the hole-spacing assembly of  FIG.  20   ; 
         FIG.  23    is a perspective view of another example hole-spacing assembly; and 
         FIG.  24    is a rear perspective view of the hole-spacing assembly of  FIG.  23   . 
     
    
    
     DETAILED DESCRIPTION 
     The present invention overcomes the problems associated with the prior art, by providing drill jig capable of drilling linearly aligned and evenly spaced holes in a workpiece (e.g., the side board(s) of cabinetry, book shelfs, etc.). In the following description, numerous specific details are set forth (e.g., spring types, fastener types, material types, etc.) in order to provide a thorough understanding of the invention. Those skilled in the art will recognize, however, that the invention may be practiced apart from these specific details. In other instances, details of well-known manufacturing practices (e.g., screw turning, plate cutting, molding, etc.) and components have been omitted, so as not to unnecessarily obscure the present invention. 
       FIG.  1    shows a perspective view of a drill jig  100  according to one embodiment of the present invention. Drill jig  100  is adapted to be used in conjunction with a drill press (not shown in  FIG.  1   ). More specifically, jig  100  mounts to the quill and table of a drill press ( FIGS.  6 A-D ) to facilitate the drilling of evenly spaced holes along a straight line in a workpiece (e.g., wood, metal, plastic, etc.). Unlike prior art stencils, jig  100  can withstand repeated use without wearing out and, therefore, maintains a high degree of accuracy and precision over time. Furthermore, jig  100  provides a much simpler and time efficient solution to drilling multiple holes in a workpiece as compared to current solutions. Another advantage is that jig  100  is adapted for use with many different drill presses having varying specifications. 
       FIG.  2    shows a perspective view of drill jig  100  exploded along a line  200 . Jig  100  includes an actuator  202 , a first biasing member  204 , a hole-spacing assembly  206 , a second biasing member  208 , a set of guides  210 , and a base  212 . Actuator  202  is configured to be fixably mounted around the quill of a drill press and also to seat the top portion of biasing member  204 . In response to advancing the chuck of the drill press toward a workpiece, actuator  202  urges downward against biasing member  204 . In this example device, biasing member  204  is a relatively stiff spring having a bottom portion that is coupled to hole-spacing assembly  206 . Responsive to actuator  202  urging biasing member  204  downward, hole-spacing assembly  206  slides downward along guides  210 . As will be discussed in further detail with reference to  FIG.  4   , hole-spacing assembly  206  is adapted to engage a hole previously drilled in a workpiece, such that the subsequent hole will be a precise, predetermined distance from the previously drilled hole. In this example device, biasing member  208  is also a spring having a top portion and a bottom portion coupled to hole-spacing assembly  206  and base  212 , respectively. In this example, guides  210  are parallel slider rods that extend vertically from base  212  to limit hole-spacing assembly  206  to only vertical movement. Base  212  is a rigid body that is adapted to be fixably mounted on a drill press table and provides an alignment edge for a workpiece. 
       FIG.  3    is a perspective view of actuator  202  exploded along a line  300 . Actuator  202  is configured to be vertically fixed with respect to a drill chuck and to urge biasing member  204  downward responsive to advancing the drill chuck downward. Actuator  202  includes a clamp  302 , a square nut  304 , a nut  306 , a threaded shaft  308 , and a coupler  310 . In this example, clamp  302  is configured to be fixed around the quill of a drill press. Clamp  302  includes a screw  312  and a corresponding nut  314  that allows clamp  302  to be mounted around quills of varying diameters within a predetermined range. Clamp  302  further includes an aperture (not visible) through which shaft  308  is disposed when actuator  202  is assembled. Shaft  308  is fixed to clamp  302  by nuts  304  and  306 , which are positioned on opposite sides of clamp  302 . That is, square nut  304  and nut  306  are threaded onto shaft  308  with the rear wall of clamp  302  tightened therebetween. The outer surfaces of square nut  304  engage the interior of clamp  302  such that square nut  304  does not rotate during the tightening of nut  306  onto threaded shaft  308 . Coupler  310  is a rigid body that includes a top portion  316  and a bottom portion  318 . Top portion  316  includes a through-hole  320  configured to receive shaft  308 . Bottom portion  318  is a cylindrical shell sized to seat the top portion of biasing member  204 . 
       FIG.  4    is an exploded perspective view of hole-spacing assembly  206  which includes a rigid body  400 , a set of bushings  402 , a set of bolts  404 , a set of nuts  406 , a protrusion  408 , and a nut  410 . 
     In the example embodiment, rigid body  400  is made up of two plates  412  and  414  that are held together by bolts  404  and corresponding nuts  406  when jig  100  is assembled. Plate  412  is configured to slidaby engage guides  210  of base  212  ( FIG.  2   ) and to be adjustably fixed to plate  414 . Plate  414  is configured to support and position protrusion  408  relative to plate  412 . 
     Plate  412  includes a pair of apertures  416 , a spring seat  418 , and a pair of slots  420 . Apertures  416  provide openings in which bushings  402  are retained. Optionally, bushings  402  may be further secured in apertures  416  via a set of respective fasteners such as, for example, press clips, C-clips, etc. Spring seat  418  is sized to fit within and/or engage the interior of the bottom portion of biasing member  204 , to maintain alignment therebetween. In this example, spring seat  418  is an integral feature of plate  412 . However, spring seat  418  may optionally be an external component that is fastened to plate  412  such as, for example, a thick washer bolted onto plate  412 . Slots  420  and an additional set of slots  422  of plate  414  are adapted to each receive an associated one of bolts  404 . Slots  420  and  422  are elongated such that the horizontal distance between plate  414  and base  212  can be adjusted. By adjusting this distance, the distance between the edge of a workpiece and the drill holes of the workpiece can be adjusted. To increase the distance, bolts  404  are loosened, plates  412  and  414  are pulled laterally away from each other, and bolts  404  are then retightened. To decrease this distance, bolts  404  are loosened, plates  412  and  414  are urged laterally toward each other, and bolts  404  are then retightened. Optionally, one or more cylindrical apertures can be substituted for each of slots  420  and  422 , so that plate  414  can be flipped upside down (to swap the positions of slot  428  and adjustment apertures  426 ) and mounted without having to laterally realign plate  414  with respect to plate  412 . 
     Plate  414  further includes a drilling aperture  424 , a set of discrete adjustment apertures  426 , and a slot  428  all aligned along the same straight line. Drilling aperture  424  provides an opening through which a drill bit passes when jig  100  is actuated. Aperture  424  also facilitates the alignment of jig  100  with respect a drill press during the mounting of jig  100  to the drill press table. For example, prior to fixing base  212  to the drill press table, the drill bit is advanced downward and the position of jig  100  with respect to the table is changed until the drill bit is aligned sufficient to pass through aperture  424 . While the drill bit is disposed through aperture  424 , base  212  is clamped to the table ( FIG.  6 A ) in a fixed position such that the bit will advance through aperture  424  along the same path every time the drill chuck is advanced downward. 
     Discrete adjustment apertures  426  are each configured to receive protrusion  408 . As shown, each of adjustment apertures  426  are in-line with aperture  424  but are located at different distances from aperture  424 . This allows the user to have a discrete number of options in terms of where to place protrusion  408 . Of course, the distance between protrusion  408  and aperture  424  dictates the distance between adjacent drill holes in the workpiece. This is because protrusion  408  is configured to engage a hole previously drilled in the workpiece. In this example, adjustment apertures  426  are shown evenly spaced apart. Those skilled in the art, however, will recognize that adjustment apertures  426  can also be located at varying distances, if desirable for a particular application. Slot  428  is also adapted to receive protrusion  408  but provides a continuous range of optional positions of protrusion  408  with respect to aperture  424 . That is, protrusion  408  can be secured anywhere along slot  428  and is not limited to a finite number of discrete positions, as is the case when protrusion  408  is mounted in one of adjustment apertures  426 . Another important aspect of plate  414  is that it can be flipped over such that the positions of slot  428  and adjustment apertures  426  are interchangeable. 
       FIG.  5    shows a perspective view of base  212  with guides  210  exploded therefrom. Base  212  is a rigid, elongated body formed from, in this example, laminated wood. Note that base can alternately formed from other materials including, but not limited to, plastic, metal, etc. Base  212  defines a cylindrical recess  500 , a pair of apertures  502 , and an edge alignment guide  504 . Recess  500  is configured to receive and seat the bottom portion of biasing member  208 . Each of apertures  502  is configured to receive a respective one of guides  210 . In this example, guides  210  are press-fit into apertures  502 . However, those skilled in the art will recognize that guides  210  can be attached to base  212  by any suitable means (e.g., threads, adhesive, etc.) without departing from the main scope of the present invention. Alignment guide  504  is a planar surface configured to slidably engage the edge of a workpiece during hole drilling operations of jig  100 . By maintaining abutment between the workpiece and alignment guide  504 , while the workpiece is advanced along jig  100 , a consistent distance between the drill holes and the edge of the workpiece is maintained. 
     Alternate alignment guides may be substituted for the flat planar surface of alignment guide  504 . For example, a set of two or more protrusions adapted to slidably engage a workpiece may extend laterally from base  212 . Such protrusions may also include components and/or features (e.g., rollers, wheels, etc.) that minimize friction with the workpiece. Additionally, such protrusions can be adjustable. 
     The operation of jig  100  will now be described with reference to  FIGS.  6 A- 6 D . 
     Prior to use, jig  100  is positioned and mounted on a drill press  600  as depicted in  FIG.  6 A . This involves first attaching clamp  302  of actuator  202  to the quill  602  of drill press  600 . With clamp  302  attached to quill  602 , base  212  is positioned on the table  604  of drill press  600  such that aperture  424  is approximately coaxially aligned with the drill bit  606  of drill press  600 . Next, drill press  600  is actuated thereby advancing quill  602  and drill bit  606  downward toward aperture  424 . While drill bit  606  is advancing downward, the lateral position of base  212  is adjusted until drill bit  606  passes through aperture  424 . With drill bit  606  disposed through aperture  424 , base  212  is fixed to table  604  using a set of C-clamps  608 . As long as base  212  remains clamped to table  604 , drill bit  606  will pass through aperture  424  every time quill  602  is advanced downward. Optionally, drill bit  606  can be substituted with a cylindrical alignment pin during the process of aligning plate  414  to achieve more accurate alignment. This is because the drill fluting could allow bit  606  to be disposed in aperture  424  even when they are not exactly coaxial. Another option is to mount bit  606  upside down in the chuck during the alignment of plate  414  such that the cylindrical end is disposed in aperture  424 . 
     Once jig  100  is mounted to drill press  600 , quill  602  is retracted and a workpiece  610  is positioned on table  604  against alignment guide  504 , as depicted in  FIG.  6 B . When quill  602  is retracted, jig  100  is in a non-actuated position, wherein both biasing members  204  and  208  are in a relaxed state. Next, an initial hole  612  is drilled into workpiece  610 . 
     After initial hole  612  is drilled into workpiece  610 , workpiece  610  is advanced to the right to approximately align initial hole  612  with protrusion  408 . Then, quill  602  is advanced downward, as depicted in  FIG.  6 C . As quill  602  advances downward, actuator  202  urges biasing member  204  downward. Because biasing member  204  is stiffer than biasing member  208 , biasing member  208  compresses before biasing member  204 . As a result, hole-spacing assembly  206  advances downward as actuator  202  advances downward. As hole-spacing assembly  206  approaches workpiece  610 , the lateral position of workpiece  610  is adjusted slightly along guides  504  until protrusion  408  engages initial hole  612 . 
     Once protrusion  408  engages initial hole  612 , the advancement of hole-spacing assembly  206  stops, while actuator  202  continues to advance downward as depicted in  FIG.  6 D . As actuator  202  continues to advance, biasing member  204  begins to compress, thereby allowing drill bit  606  to advance into workpiece  610 . Once a sufficient bore depth is achieved, quill  602  is retracted, thereby decompressing springs  204  and  208 . Of course, decompression of springs  204  and  208  causes hole-spacing assembly  206  to return to a non-actuated position, lifting protrusion  208  from initial hole  612 . Finally, workpiece  610  is fed to the right and the process is repeated, each time with protrusion  208  engaging the most recently drilled hole, until a predetermined number of linearly aligned, and evenly spaced apart, holes have be bored. 
       FIG.  7    is an exploded perspective view of an alternate , assembly  700 . Hole-spacing assembly  700  is substantially similar to hole-spacing assembly  206 , except that plate  414  has been substituted with alternate plate  702 . Therefore, the features and elements of hole-spacing assembly  700  that are identical to those of hole-spacing assembly  206  are denoted by like reference numbers and withheld from the following description to avoid redundancy. 
     Plate  702  includes a set of slots  704 , a drilling aperture  706 , a set of discrete adjustment apertures  708 , a second set of slots  710 , and a second set of discrete apertures  712 . Slots  704  are configured to receive bolts  404  to facilitate the adjustable mounting of plate  702  to plate  412 . Drilling aperture  706  is substantially identical to drilling aperture  424  of plate  414 , in that it provides an opening through which a drill bit passes when jig  100  is actuated. Aperture  706  also facilitates the alignment of jig  100  with respect to a drill press during the mounting of jig  100  to the drill press table. Adjustment apertures  708  are each configured to receive protrusion  408 . As shown, each of adjustment apertures  708  are in-line with aperture  706 , but spaced therefrom at different distances. This allows the user to have a discrete number of options in terms of where to place protrusion  408 . As in previously described example embodiments, the distance between protrusion  408  and aperture  706  dictates the distance between adjacent drill holes in the workpiece. Slots  710  are also adapted to receive protrusion  408 , but provide discrete, continuous ranges of optional positions of protrusion  408  with respect to aperture  706 . By having multiple discrete slots  710 , as opposed to a single long slot, the strength of plate  702  is increased. Discrete apertures  712  can also receive protrusion  408  and provide yet another option with respect to where protrusion  408  can be placed along plate  702  (i.e., between slots  710 ). 
       FIG.  8    is an exploded perspective view of another example hole-spacing assembly  800 . Hole-spacing assembly  800  is substantially similar to hole-spacing assembly  206 , except that plate  414  and protrusion  408  have been replaced with an alternate plate  802  and slider assembly  804 , respectively. Therefore, the features and elements of hole-spacing assembly  800  that are identical to those of hole-spacing assembly  206  are denoted by like numbers and withheld from the following description to avoid redundancy. 
     Plate  802  includes a set of slots  806 , a drilling aperture  808 , a set of discrete adjustment apertures  810 , and indicia  812 . Slots  806  are configured to receive bolts  404  to facilitate the coupling and lateral adjustment of plate  802  with respect to plate  412 . Drilling aperture  808  is substantially identical to drilling aperture  424  of plate  414  in that it provides an opening through which a drill bit passes when jig  100  is actuated. Aperture  808  also facilitates the alignment of jig  100  with respect to a drill press during the mounting of jig  100  to the drill press table. Discrete adjustment apertures  810  are each configured to receive protrusion  408  to provide an alternative to slider assembly  804 . That is, a user can optionally remove slider assembly  804 , position protrusion  408  in any one of adjustment apertures  810 , and use jig  100  as previously described. As shown, each of adjustment apertures  810  is in-line with drilling aperture aperture  808 , but located at different distances from drilling aperture  808 . This allows the user to have a discrete number of options in selecting where to place protrusion  408 . Indicia  812  indicates the linear distance between drilling aperture  808  and a protrusion  814  (shown in  FIG.  9   ) located at the bottom of slider assembly  804 . In the example embodiment, indicia  812  is a printed substrate adhered to the top surface of plate  802 . However, indicia  812  may be formed directly on plate  802  by some suitable means including, but not limited to, molding, engraving, painting, etc. 
     Slider assembly  804  is coupled to slide along plate  802 , so that protrusion  814  can be selectively positioned at any distance from drilling aperture  808 , within the range of indicia  812 . Once in position, slider assembly  804  is also configured to be fixed in place with respect to plate  802 , as will be described with reference to upcoming  FIG.  9   . 
       FIG.  9    is a cross-sectional view of slider assembly  804  taken along line A-A of  FIG.  8   . Slider assembly  804  includes a body  900  and a thumb screw  902 . Body  900  is a rigid C-shaped member defining an internal channel  904 , protrusion  814 , and a threaded aperture  906 . Channel  904  is adapted to slidably engage the outer surface of plate  802  such that protrusion  814  remains in-line with drilling aperture  808  regardless of the distance therebetween. Protrusion  814  functions similar to protrusion  408  in that it is adapted to engage a previously drilled hole. Threaded aperture  906  is configured to receive thumb screw  902  such that body  900  can be fixed in place along plate  802  by tightening screw  902 . Of course, the user can adjust the position of body  900  along plate  802  by loosening screw  902 , moving the position of body  900  to a desired point along indicia  812 , and then retightening screw  902 . 
       FIG.  10    is a perspective view of a drill attachment  1000  that mounts on a drill to facilitate the drilling of linearly aligned, evenly spaced holes in a workpiece. In the example embodiment, attachment  1000  is formed from polycarbonate which is both rigid and transparent. The transparency of attachment  1000  allows the user to see the underlying workpiece when drilling holes therein. 
     Attachment  1000  includes a set of mounting slots  1002 , a drilling aperture  1004 , a set of discrete adjustment apertures  1006 , a set of adjustment slots  1008 , a second set of discrete apertures  1010 , and an alignment guide  1012 . Slots  1002  facilitate the mounting of attachment  1000  to a drill (e.g., a portable drill press, a hand-held drill motor, etc.). Drilling aperture  1004  provides an opening through which a drill bit passes during the operation of attachment  1000 . Discrete adjustment apertures  1006  are each configured to selectively receive protrusion  408 . As shown, each of adjustment apertures  1006  are in-line with drilling aperture  1004 , but is spaced a different distance from drilling aperture  1004 . The spaced apertures  1006  provide a user with a discrete number of positioning options for protrusion  408 . The distance between protrusion  408  and aperture  1004  dictates the distance between drill holes in the workpiece. Slots  1008  are also adapted to receive protrusion  408  but provide discrete continuous ranges of optional positions of protrusion  408  with respect to aperture  1004 . Having multiple discrete slots  1008 , as opposed to a single long slot, increases the strength of attachment  1000 . Discrete apertures  1010  provide additional options for positioning protrusion  408  along attachment  1000 , between slots  1008 . 
     Alignment guide  1012  is flat planar surface that is adapted to engage a workpiece during drilling operations such that a sequence of holes drilled in the workpiece are in a straight line parallel to the edge of the workpiece. As shown in  FIG.  10   , alignment guide  1012  is formed integrally (e.g., machined, cast, etc.) with the body of attachment  1000 . Alternatively, alignment guide  1012  can include a separate structure fixed (e.g., bolted, welded, adhered, etc.) to the body of attachment  1000 . 
       FIG.  11    shows a front view of attachment  1000  mounted to a portable drill press  1100 , via a set of screws  1102  and an associated set of nuts  1104 . Portable drill press  1100  is coupled to, and driven by, a portable drill  1106 . This combination provides a portable means for drilling linearly aligned and evenly spaced holes in workpieces that might be too large and/or inconvenient for a standard drill press. For example, if a workpiece is already fixed vertically to a wall, but requires evenly spaced and linearly aligned drill holes, it would be beneficial to use attachment  1000  to drill the holes rather than to remove the workpiece, drill the holes on a press, and reattach the workpiece to the wall. 
     Portable drill press  1100  includes a base  1108 , a set of guides  1110 , a frame  1112 , a biasing member  1114 , a drive shaft  1116 , and a chuck  1118 . Base  1108  is a rigid structure that facilitates the mounting of portable drill press  1100  to attachment  1000 . Guides  1110  are rigid parallel rods that are fixably attached to base  1108  to extend perpendicularly therefrom. Frame  1112  is a rigid structure coupled to slide downward along guides  1110  in response to urging portable drill  1106  toward attachment  1000 . Biasing member  1114  is operative to urge frame  1112  away from attachment  1000 , so that chuck  1118  is returned to a retracted position when drill  1106  is not urged toward attachment  1000 . In the example embodiment, biasing member  1114  is a coil spring that is coaxially disposed around one of guides  1110 , between base  1108  and frame  1112 . Drive shaft  1116  extends through frame  1112  and is free to rotate therein. Drive shaft  1116  is also vertically fixed with respect frame  1112 , so that urging shaft  1116  downward also urges frame  1112  downward. Chuck  1118  is fixed to the bottom end of drive shaft  1116  and rotates responsive to rotating the top of drive shaft  1116  using drill  1106 . In this example, the top end of drive shaft  1116  is engaged in a chuck  1120  of drill  1106 , and a drill bit  1122  is rotated when drill  1106  rotates drive shaft  1116 . Portable drill press  1100 , attachment  1000 , and drill  1106 , together, operate similar to jig  100  and drill press  600 , in that protrusion  408  engages a previously drilled hole in order provide a reference location for the subsequently drilled hole. Unlike jig  100 , portable drill press  1100  can be moved relative to the workpiece rather than feeding the workpiece to the cutting tool. 
     A plurality of standoffs  1124  define a planar surface to abut the top surface of a workpiece. Standoffs  1124  provide clearance for nut  410 , the heads of screws  1102 , and any other attachment devices that project below the under surface  1126  of attachment  1000 . In the embodiment of  FIG.  10   , standoffs  1124  are bumps. However, standoffs  1124  can be any convenient structures including, but not limited to, spaced ribs running the length of attachment  1000 . 
     In the previously described embodiments, plate  412 , plate  414 , plate  702 , plate  802 , and drill attachment  1000  are all formed from rigid transparent material, thereby enabling a user to see the workpiece therethrough. More specifically, plate  412 , plate  414 , plate  702 , plate  802 , and drill attachment  1000  can all be formed from polycarbonate. This helps the user see the underlying workpiece during drilling operations. In alternate embodiments, however, any of plate  412 , plate  414 , plate  702 , plate  802 , and drill attachment  1000  can be formed from other transparent materials (e.g. acrylic glass) and/or opaque materials (e.g., metal, plastic, wood, etc.). 
       FIG.  12    is a flowchart  1200  summarizing a method of manufacturing a drill jig. In a first step  1202 , an edge alignment guide is provided. Then, in a second step  1204 , a hole-spacing assembly, including a protrusion configured to engage a preexisting hole, is provided. Next, in a third step  1206 , a second guide configured to facilitate movement of the hole-spacing assembly is provided. Then, in a fourth step  1208 , the second guide is coupled to the hole-spacing assembly. Next, in a fifth step  1210 , a biasing member is provided. Then, in a sixth step  1212 , the biasing member is coupled to the hole-spacing assembly. Next, in a seventh step  1214 , an actuator is provided. Finally, in an eighth step  1216 , the actuator is coupled to the biasing member. 
       FIG.  13    shows a perspective view of another example drill jig. Drill jig  1300  is adapted to be used in conjunction with a drill press (not shown in  FIG.  13   ). More specifically, jig  1300   mounts to the quill and table of a drill press to facilitate the drilling of evenly spaced holes along a straight line in a workpiece (e.g., wood, metal, plastic, etc.). 
       FIG.  14    shows a perspective view of drill jig  1300  exploded along lines  1400 . Jig  1300  includes an actuator assembly  1402 , a first biasing member  1404 , a hole-spacing assembly  1406 , a set of biasing members  1408 , a set of guides  1410 , and a base  1412 . Actuator assembly  1402  is configured to be fixably mounted around the quill of a drill press and also to seat the top portion of biasing member  1404 . In response to advancing the chuck of the drill press toward a workpiece, actuator assembly  1402  urges downward against biasing member  1404 . In this example device, biasing member  1404  is a relatively stiff spring having a bottom portion that is coupled to hole-spacing assembly  1406 . Responsive to actuator assembly  1402  urging biasing member  1404  downward, hole-spacing assembly  1406  slides downward along guides  1410 . Hole-spacing assembly  1406  is adapted to engage a hole previously drilled in a workpiece, such that the subsequent hole will be a precise, predetermined distance from the previously drilled hole. In this example device, each of biasing members  1408  is also a spring having a top portion and a bottom portion coupled to hole-spacing assembly  1406  and base  1412 , respectively. In this example, guides  1410  are parallel slider rods that extend vertically from base  1412  to limit hole-spacing assembly  1406  to only vertical movement. Base  1412  is a rigid body that is adapted to be fixably mounted on a drill press table and provides an alignment edge for a workpiece. As shown, base  1412  includes two apertures  1414  into which respective guides  1410  are permanently press fit. 
       FIG.  15    is a perspective view of actuator assembly  1402  exploded along lines  1500 . Actuator assembly  1402  is configured to be vertically fixed with respect to a drill chuck and to urge biasing member  1404  downward responsive to advancing the drill chuck downward. Actuator assembly  1402  includes a U-bolt  1502 , a body  1504 , a set of washers  1506 , and a set of nuts  1508 . In this example, U-bolt  1502  and body  1504  are, together, configured to be fixed around the quill of a drill press. Body  1504  includes a pair of apertures  1510  configured to receive respective threaded regions  1512  of U-bolt  1502 . Once regions  1512  are disposed through apertures  1510 , respective nuts  1508  are threaded on regions  1512  with respective washers  1506  disposed between body  1504  and nuts  1508 . Body  1504  is constructed of, for example, steel and further includes a biasing member engaging feature  1514  configured to seat the top portion of biasing member  1404 . 
       FIG.  16    is a rear perspective view of body  1504 . As shown, feature  1514  is a rectangular plate that is perpendicularly attached to another rectangular plate  1600  via a weld  1602 . Likewise, plate  1600  is also attached via a weld  1604 . 
       FIG.  17    is an exploded perspective view of hole-spacing assembly  1406 , which includes a body  1700 , a set of bushings  1702 , a set of retainer clips  1704 , a set of hex screws  1706 , an extendable arm  1708 , a roll pin  1710 , a protrusion  1712 , and a set of square nuts  1714 . 
     Body  1700  is a rigid body configured to slide down guides  1410  responsive to being urged upon by biasing member  1404  and slide upward when the force exerted thereon by biasing members  1408  exceeds that of biasing member  1404 . Body  1700  includes a biasing member engaging feature  1716 , a set of apertures  1718 , a channel  1720 , and a set of threaded apertures (not visible). Biasing member engaging feature  1716  is configured to seat the bottom portion of biasing member  1404 . Apertures  1718  are configured to receive bushings  1702 . Once bushings  1702  are disposed through apertures  1718 , they are retained in place with respective retainer clips  1704 . Channel  1720  is configured to slidably receive arm  1708 . Once arm  1708  is at a desired position within channel  1720 , arm  1708  is locked in place by tightening screws  1706  in the respective threaded apertures of body  1700 . 
     Arm  1708  is curved metal structure configured to support and position protrusion  1712  with respect to body  1700 . Arm  1708  includes a first portion  1722 , a second portion  1724 , and a third portion  1726 . First portion  1722  is configured to slide within channel  1720  and second portion  1724  is configured to redirect protrusion  1712  toward body  1700 . Third portion  1726  is an intermediate portion between first portion  1722  and second portion  1724 . In the example embodiment, third portion  1726  is a 180 degree arc. However, third portion  1726  may alternatively be generally squared or any other shape that redirects second portion  1724  toward body  1700  without deviating from the present invention. The general redirection of third portion  1726  defines a crotch  1728  that provides an increased range in terms of the distance at which protrusion  1712  can be positioned with respect to body  1700 . In this example, protrusion  1712  is a threaded shaft that is mounted in an aperture  1730  of second portion  1724  of arm  1708  via threaded square nuts  1714 . Roll pin  1710  is compression fit into another aperture  1732  of arm  1708  to prevent arm  1708  from being disposed too far in channel  1720  by contacting the side of body  1700  when second portion  1724  is urged toward body  1700 . 
       FIG.  18    shows a side view of body  1700 . In the example embodiment, body  1700  is a unitary aluminum body formed by extrusion. 
       FIGS.  19 A and  19 B  are top views of arm  1708  attached to body  1700  showing the range at which protrusion  1712  can be positioned with respect to body  1700 . 
       FIG.  19 A  shows arm  1708  positioned with respect to body  1700  such that the distance (D min ) between a drill bit location  1900  and a previously drilled hole (under protrusion  1712 ) is the minimum for this particular device. Of course, D min  can be even smaller by making second portion  1724  longer such that protrusion  1712  can extend closer to location  1900 . 
       FIG.  19 B  shows arm  1708  positioned with respect to body  1700  such that the distance (D max ) between a drill bit location  1900  and a previously drilled hole is the maximum for this particular device. Of course, D max  can be even greater by making first portion  1722  longer such that protrusion  1712  can extend further from location  1900 . It should be recognized that, in this particular embodiment, the distance between location  1900  and protrusion  1712  can be any distance between D min  and D max  simply by loosening screws  1706 , adjusting the position of arm  1708  with respect to body  1700 , and then tightening screws  1706  until arm  1708  is locked in position. 
       FIG.  20    shows a perspective view of a drill jig  2000  exploded along a line  2002  according to another embodiment of the present invention. Jig  2000  is substantially identical to jig  1300 , the only difference being that jig  2000  has a modified actuator  2004  and hole-spacing assembly  2006  which, together, make biasing members  1408  obsolete. The features of jig  2000 , actuator  2004 , and assembly  2006  that are identical to those of jig  1300  are, therefore, denoted by like reference numbers and withheld from the following description. 
     In jig  2000 , biasing members  1408  are not required to urge assembly  2006  back upward after actuation. Rather, jig  2000  includes a first biasing member engaging feature  2008  and a second biasing member engaging feature  2010 . Feature  2008  is configured to fix the top of biasing member  1404  to actuator  2004  and feature  2010  is configured to fix the bottom of biasing member  1404  to assembly  2006 . As actuator  2004  is returned to a non-actuated position, the tension imparted on biasing member  1404  by feature  2008  lifts feature  2010  and, therefore, assembly  2006  back into a non-actuated position. 
       FIG.  21    is a rear perspective view of a body  2100  of actuator  2004  and feature  2008  assembled. Body  2100  is substantially identical to body  1504 , the only difference being that body  2100  further includes an aperture  2102  that receives feature  2008 . In this example, feature  2008  is a roll pin that is compression fit into aperture  2102 . The length of feature  2008  is greater than the outer diameter of biasing member  1404  such that feature  2008  engages biasing member  1404  when biasing member  1404  is seated on feature  1514 . 
       FIG.  22    is a rear perspective view of a body  2200  of assembly  2006  and feature  2010  assembled. Body  2200  is substantially identical to body  1700 , the only difference being that body  2200  further includes an aperture  2202  that receives feature  2010 . In this example, feature  2010  is a roll pin that is compression fit into aperture  2202 . The length of feature  2010  is also greater than the outer diameter of biasing member  1404  such that feature  2010  engages biasing member  1404  when biasing member  1404  is seated on feature  1716 . Those skilled in the art will recognize that other biasing member engaging features (e.g., permanent barbs, removable cotter pins, etc.) may be substituted for features  2008  and  2010  without departing from the main scope of the present invention. 
       FIG.  23    is a perspective view of an alternate extendable arm assembly  2300  that may be substituted for arm  1708  without further modification to jig  1300 . Assembly  2300  provides additional advantages. For example, assembly  2300  can be disassembled and, therefore, packaged at a reduced volume. As another example, assembly  2300  can be mass manufactured more efficiently. It should be recognized that assembly  2300  slidably engages body  1700  in the same way that arm  1708  does. In other words, body  1700  and screws  1706  require no modification to receive assembly  2300 . 
       FIG.  24    is an exploded rear perspective view of extendable arm assembly  2300 , which includes a body  2400 , a guide  2402 , a pin  2404 , and a plurality of adapter caps  2406  (only one shown). Body  2400  is a rigid monolithic structure formed, for example, by injection molding Acrylonitrile Butadiene Styrene (ABS) plastic. Body  2400  defines a recess  2408  and an arm  2410 . Recess  2408  is configured to receive guide  2402 , which is a straight metal bar removably press fit therein during user assembly. Indeed, guide  2402  is configured to slide in channel  1720  of body  1700 . Arm  2410  is configured to position pin  2404  and, therefore, cap  2406  with respect to guide  2402 . Arm  2410  defines an aperture  2412  through which pin  2404  is press fit. Pin  2404  is a solid cylindrical metal pin but may alternately be a roll pin or the like without departing from the main scope of the invention. Cap  2406  is configured to be press fit onto the bottom portion of pin  2404  so that it can engage previously drilled holes in a work piece. Cap  2406  is one of many interchangeable caps that are adapted to fit into different drill-hole sizes. Indeed, all of caps  2406  have the same size cylindrical recess that receives pin  2404  but different exterior diameters to accommodate for different drill-hole sizes. In this example, caps  2406  are formed from molded ABS plastic but may be formed by any suitable manufacturing process and/or material. 
     The description of particular embodiments of the present invention is now complete. Many of the described features may be substituted, altered or omitted without departing from the scope of the invention. For example, alternate fasteners (e.g., screws, compression pins, etc.) may be substituted for the bolts used to fasten the plates of the hole-spacing assembly. As another example, alternate devices and/or features (e.g., pins, integrally molded protrusion, nylon screws, etc.) may be substituted for the protrusion. In addition, various types of drill stops, in the press mechanisms or on the drill bits themselves, can be used in combination with the described embodiments to limit the depth of holes drilled in workpieces These and other deviations from the particular embodiments shown will be apparent to those skilled in the art, particularly in view of the foregoing disclosure.