Abstract:
A pocket hole jig utilizes a pair of adjustable drill guides attached at the front of a movable carriage to enable self-adjustment in pocket hole placement over a range of workpiece thicknesses. The carriage is slidably received on an angled base member and may be moved toward or away from a vertical base member used to support wooden workpieces. A locking mechanism retains the carriage in its adjusted position. The pair of drill guides are adjustably positioned towards or away from one another and relative to the pocket hole jig axis of symmetry, locating the pair of pocket hole drilling locations.

Description:
RELATED APPLICATIONS 
     The present application claims the benefit of priority under 35 USC §119(e) to U.S. Provisional Application No. 62/234,928, filed on Sep. 30, 2015, which is incorporated by reference herein for all that it contains. 
    
    
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present invention relates to jig used to join two workpieces and, more particularly, to a pocket hole jig. More specifically, the present invention relates to a pocket hole jig that self-adjusts to correctly position a pair of pocket holes, symmetrically located about the centerline of the jig, over the clamp range of wood workpiece thicknesses. 
     Description of the Related Art 
     Pocket hole joinery is used extensively in woodworking as a quick and easy way to join two wood workpieces. A pocket hole is a pilot hole drilled at an angle in a first wood workpiece to align a screw for fastening to a second workpiece. A step drill creates a counterbored hole for the head of the pocket screw and a smaller diameter for body clearance in the last half-inch or so. This manner of joint attachment is visually clean—as the pocket holes and pocket hole screw heads hide in the internal, underside construction areas of woodworking projects. 
     Initially, pocket hole joinery required chisel work followed by a brace and bit. A present-day user now uses a jig with an electric hand drill, easily and quickly making the joint. Several jigs are commercially available, albeit costly, complex, and bulky. Often complicated to use, some having a poor design generate holes with ragged edges. 
     SUMMARY OF THE INVENTION 
     The present invention provides a pocket hole jig having a one-piece base, a sliding carriage with a simple clamping mechanism, an accurate drill stop assembly, two symmetrically adjustable drill guides, an adjustable side stop mechanism, and a sealed dust port chamber. The jig of the present invention self-adjusts to the thickness of the wood, accurately creating the pocket hole at the correct position for any wood thickness appropriate for use within the clamp holding the two workpieces. Once initially set, the step drill stop collar requires no further adjustments within the clamp range of workpiece widths. Screw selection is likewise simplified, requiring thickness measurement of the second workpiece, to which is added ½ inch for total screw length. 
     An aspect of embodiments in accordance with the present invention is a self-adjusting pocket hole jig comprising: a jig base comprising: a vertical base member, a horizontal base member attached to said vertical base member, and an angled base member attached to said horizontal member, and wherein in its assembled operable condition there is no movement among the individual base members of said jig base; a carriage slidably mounted to said angled base member and in its assembled operable condition adapted for movement toward and away from said vertical base member of said jig base; a pair of adjustable drill guides, each slidably mounted to a front surface of said carriage in a side-to-side reciprocating manner and in its assembled operable condition adapted for movement toward and away from one another, and wherein each of said adjustable drill guides has a drill guide bore formed therein, said drill guide bore extending from an upper surface to a front surface thereof; and a depth stop plate attached to said jig base and extending over each of said adjustable drill guides in a vertically superposed manner, wherein said depth stop plate has a pair of apertures formed therein, each of said pair of apertures located over a separate one of said pair of adjustable drill guides and each vertically co-located over a separate one of the drill guide bores. 
     These and other objects, aspects, and features of the present invention will be better understood from the following description of embodiments when read in conjunction with the appended drawing figures. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Embodiments in accordance with the present invention are described below in connection with the accompanying drawing sheets. 
         FIG. 1  is a side elevation view of a self-adjusting pocket hole jig in accordance with the present invention. 
         FIG. 2  is a top view in perspective of the self-adjusting pocket hole jig of  FIG. 1 . 
         FIG. 3  is an exploded side elevation view of the self-adjusting pocket hole jig of  FIG. 1 . 
         FIG. 4  is a partial cross-sectional view of the carriage locking mechanism in accordance with the present invention. 
         FIG. 5  is an enlarged partial cross-sectional view of the manner of connecting the slide plate and carriage in accordance with the present invention. 
         FIG. 6  is a perspective view, with portions shown in phantom, of the slide plate in accordance with the present invention. 
         FIG. 7  is schematic representation of the carriage locking mechanism with the slide plate clamped against the angled base member in accordance with the present invention. 
         FIG. 8  is a schematic representation, similar to  FIG. 7 , of the carriage locking mechanism with the slide plate clamped against the angled base member and the carriage position moved forward in accordance with the present invention. 
         FIG. 9  is a schematic representation in side elevation of the self-adjusting pocket hole jig with a clamped workpiece of narrow thickness in accordance with the present invention. 
         FIG. 10  is a schematic representation in side elevation, similar to  FIG. 9 , of the self-adjusting pocket hole jig with a clamped workpiece of medium thickness in accordance with the present invention. 
         FIG. 11  is a schematic representation in side elevation, similar to  FIGS. 9 and 10 , of the self-adjusting pocket hole jig with a clamped workpiece of wide thickness in accordance with the present invention. 
         FIG. 12  is a front elevated perspective view of a self-adjusting pocket hole jig in accordance with the present invention. 
         FIG. 13  is a rear bottom perspective view of a self-adjusting pocket hole jig in accordance with the present invention. 
         FIG. 14  is a front perspective view of a self-adjusting pocket hole jig, with the vertical base removed, in accordance with the present invention. 
         FIG. 15  is a front perspective view, with portions shown in phantom and portions shown exploded, of a right adjustable drill guide in accordance with the present invention. 
         FIG. 16  is a front perspective view, similar to  FIG. 15 , with portions shown in phantom, of a left adjustable drill guide in accordance with the present invention. 
         FIG. 17  is a side elevation view of a spacing control shaft in accordance with the present invention. 
         FIG. 18  is a side elevation view, with portions shown in phantom and portions shown exploded, of a right adjustable drill guide in accordance with the present invention. 
         FIG. 19  is an elevated front perspective view of a carriage in accordance with the present invention. 
         FIG. 20  is a perspective view of a center divider in accordance with the present invention. 
         FIG. 21  is a top plan view, with portions shown in phantom, of a carriage and attached adjustable drill guides, the drill guides positioned adjacent to one another, in accordance with the present invention. 
         FIG. 22  is a top plan view, similar to  FIG. 21 , with portions shown in phantom, of a carriage and attached adjustable drill guides, the drill guides positioned apart from one another, in accordance with the present invention. 
         FIG. 23  is a side elevation view, in cross-section, of storage cavities formed in a vertical base member, and articles stored therein, in accordance with the present invention. 
         FIG. 24  is a schematic representation in side elevation of two thick workpieces having a pocket hole formed prior to their being joined in accordance with the present invention. 
         FIG. 25  is a schematic representation in side elevation, similar to  FIG. 24 , of two workpieces of medium thickness having a pocket hole formed prior to their being joined in accordance with the present invention. 
         FIG. 26  is a schematic representation in side elevation, similar to  FIGS. 24 and 25 , of two workpieces of narrow thickness having a pocket hole formed prior to their being joined in accordance with the present invention. 
         FIG. 27  is an elevated side perspective view of a pocket hole jig with a side stop in accordance with the present invention. 
         FIG. 28  is an elevated side perspective view, similar to  FIG. 27 , of a pocket hole jig with a side stop stored within the vertical base member in accordance with the present invention. 
         FIG. 29  is a partial elevated side perspective view shown a manner of operation of a carriage positional indicator and a lookup table positioned on an angled base member in accordance with the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The self-adjusting pocket hole jig is disclosed herein with respect to exemplary embodiments. The embodiments are disclosed for illustration of the self-adjusting pocket hole jig and a manner of operation, and are not limiting except as defined in the appended claims. 
     A pocket hole jig  10  in accordance with the present invention is shown in  FIGS. 1 and 2 , and the exploded view of  FIG. 3 . The pocket hole jig  10  includes a jig base  14  formed of three attached base members, a vertical member  18 , a horizontal member  24 , and an angled member  28 . In a presently preferred embodiment a plurality of cavities for storage are provided within the vertical base  18 , (a stored step drill and a stored driver are shown in  FIGS. 1-3 ). 
     A carriage  34  travels along the angled base  28 , a rear surface  38  slidably engaging the inclined front surface  44  of the angled base  28 . A slide channel  52  formed in the angled base member (see  FIG. 2 ) slidably receives a slide plate  56 , the slide plate  56  having an outer surface of matching configuration to the slide channel  52 . 
     As described in greater detail below, the slide plate  56  is attached to the carriage  34 , with a slide alignment boss  62  extending from the slide plate  56  and received within a slide alignment slot  64  formed in the rear surface of the carriage  34 . This manner of interconnection assists in maintaining the relative positional alignment between the slide plate  56  and the attached carriage  34 . A top stop  68  attached at the top end of the angled base member  28  and overlying the angled base slide channel  52  (shown removed in  FIG. 2 ), secures the slide plate  56  within the slide channel  52 . 
     A front surface  78  of the carriage  34  receives a pair of laterally adjustable drill guides  84 ,  86 . A wooden workpiece  92  is shown clamped between inner surfaces  96 ,  98  of the vertical and horizontal bases  18 ,  24 , and front surfaces of the pair of drill guides  102 ,  104 . 
     Adjustments due to variance in the thickness of workpieces are obtained through movement of the carriage  34  along the inclined front surface  44  of the angled base  28 . When the front surfaces  102 ,  104  of the pair of adjustable drill guides  84 ,  86  contact the outer workpiece surface, a clamping mechanism actuated through a clamping shaft  106  attached to a clamping adjustment knob  108 , tightens the carriage/angled base interface, preventing further movement of the carriage  34  or of the workpiece  92  when the carriage  34  is lowered to abut the outer workpiece surface. A vertical slot  112  formed in the angled base  28  enables vertical movement of the clamping shaft  106  and attached clamping adjustment knob  108  when the clamping mechanism is loosened to permit movement of the carriage  34 . 
     As also shown in  FIGS. 1-3 , a step drill  114  is supported by a depth stop plate  116 , which extends forward to a position overlying both pair of drill guides  84 ,  86 . A pair of laterally elongated slots  124  are provided (see  FIG. 2 ), each extending over a separate one of the pair of adjustable drill guides  84 ,  86 . The elongated slots  124  enable placement of the step drill  114  in the drill guide of choice, over the range of lateral positions—as adjusted by a drill guide spacing control knob  128 . 
     A step drill collar  132  has a diameter wider than the width of the elongated slots  124 , providing a vertical limit to passage of the step drill  114  into the adjustable drill guides  84 ,  86 . The step drill collar  132  arrests further downward motion of the step drill  114  when the bottom surface of the step drill collar  132  reaches the upper surface of the depth stop plate  116 . 
     A pair of guide rods  134  control horizontal movement of the depth stop plate  116  (only one shown in  FIGS. 1 and 2 ). Bottom cap screws  136  restrict upward vertical movement of the guide rods  134 , and downward movement is restricted by a reduction in diameter of the guide rods  134  as they extend through bottom support grooves  138 . The pair of guide rods  134  are received within a pair of guide rod apertures  142  formed in and extending vertically through the carriage  34  (see  FIG. 19 ). 
     Drilling generates wood chips and dust. A network of ducting formed in the drill guides and the carriage body routes this debris away from the step drill. A shop vac connection  144  located on one side of the carriage  34  enables the easy evacuation of the accumulating chips and dust during drill operation. 
       FIGS. 4-8  show additional details of the clamping mechanism. The slide channel  52  formed within the angled base  28  slidably receives the slide plate  56 , which has an outer surface of matching configuration to the slide channel  52 . The slide plate  56  is attached to the carriage  34  using preferably four shoulder screws  152  received within four shoulder screw apertures  154  that extend through the slide plate  56  and partially into the carriage  34 . A compression spring  156  is received within each aperture and rests against a lower shoulder  158  formed therein. The compression springs  156  permit the limited separation of the carriage  34  from the slide plate  56  while maintaining their attachment. 
     A centrally located slide alignment boss  164  extends from a rear surface  166  of the slide plate  56  and is received within a slide alignment slot  168  formed in a rear surface  172  of the carriage  34 . The slide alignment boss  164  assists in further maintaining relative positional alignment between the slide plate  56  and the attached carriage  34 . 
     A threaded clamping shaft  182  extends through the vertical slot  112  formed in the angled base  28 , then through a clamping shaft passage  184  formed within the slide plate  56 , terminating within a closed-end aperture  186  formed in the carriage  34 . The clamping adjustment knob  108  attaches to the outer end of the threaded clamping shaft  182 , enabling the easy grasping and rotation by a user. 
     A clamping nut  192  is received mid-way along the threaded clamping shaft  182 . The inside surface of the slide channel adjacent the vertical slot  112  is recessed along its length to form an extended nut housing recess  196  with a nut securement base surface  198 . Upon a tightening rotation of the threaded clamping shaft  182 , the clamping nut  192 , moving in an outward direction, toward the clamping adjustment knob  108 , enters the nut housing recess  196  within the vertical slot  112 . 
     Continued tightening of the threaded clamping shaft  182  eventually causes the clamping nut  192  to reach the nut securement base surface  198 , preventing further outward movement of the clamping nut  192 . As shown by  FIG. 7 , the clamping mechanism has secured the vertical position of the threaded clamping shaft  182 , the slide plate  56 , and the attached carriage  34 . A flat clamping shaft washer  204  and a split clamping shaft washer  208  are preferably received upon the threaded clamping shaft between the outer surface of the angled base  28  and the clamping adjustment knob  108  to prevent the uncommanded loosening of the clamping adjustment knob  108  while in this vertically locked position. 
     With reference to  FIG. 8 , upon further rotation of the clamping shaft within the threaded carriage aperture, the threaded clamping shaft  182  moves forward within the clamping nut  192 , resulting the forward movement of the carriage  34  (in the direction of Arrow A), separating the carriage  34  from the slide plate  56  (as permitted by the shoulder screw-compression spring connection between the two). This forward movement of the carriage  34  places additional pressure against the workpiece, securing its position within the jig during drilling. 
     Movement of the carriage  34  along the angled base  28  permits variance in the distance between the drill guide surface of the carriage  34  and the inner surface of the vertical member  18 , and thus accommodation to workpieces  92  of different thickness.  FIGS. 9-11  show such adjustability, while maintaining drill positioning relative to the workpiece at the desired angle and depth. The user never need change the depth stop setting of the drill bit collar for materials within the width-range provided. Providing the correct screw clearance for all drilled pocket hole joints, regardless of workpiece thickness, assures the tightest possible joints. 
     A pair of guide rods  134  (see  FIGS. 12 and 13 ), control horizontal movement of the depth stop plate  116 . Vertical movement of the guide rods  134  in the upward direction is restricted by the angled undersides of the flat head bottom cap screws  136 , and in the downward direction by the reduced diameter of the guide rods  134  at their lower ends, fitting in the bottom support grooves  138 . 
     In  FIG. 14  the pair of adjustable drill guides  84 ,  86  are attached to the carriage  34  using a dovetail rail and groove connection. A pair of dovetail rails  216  are formed in a front surface of the carriage  34 . A pair of dovetail grooves  218  of corresponding dimensions are formed in a rear surface of each of the pair of adjustable drill guides  84 ,  86 . The pair of adjustable drill guides  84 ,  86  are slidably received upon the protruding pair of dovetail rails  216 . Such manner of mounting the pair of drill guides  84 ,  86  to the carriage  34  enables the high-precision lateral placement of the drill guides  84 ,  86  when establishing the location of the pocket holes. 
     The spacing between the pair of drill guides  84 ,  86  is user adjustable, using a threaded spacing control shaft  224  that extends through both of the drill guides  84 ,  86 . As shown in  FIG. 17 , the spacing control shaft  224  has a length of right hand thread  228  and a length of left hand thread  232  separated by a center groove  234 . As is shown in  FIG. 14  a center divider  238  projects from the front surface of the carriage  34  and a control shaft support opening  240  formed mid-ways along the front face (see  FIG. 20 ), receives the center groove  234 , providing a bearing surface to support the spacing control shaft  224 . 
     For purposes of identification only, a left/right orientation is placed upon the pair of drill guides  84 ,  86 , as viewed from the workpiece towards the carriage—a right drill guide  84  and a left drill guide  86 . The spacing control shaft  224  is received within a control shaft opening  242  formed in each of the adjustable drill guides, with left-hand internal threads in the right drill guide control shaft opening  242   a  and with right-hand internal threads in the left drill guide control shaft opening  242   b . The spacing control knob  128  attaches to one end of the spacing control shaft  224 , and by rotation of the spacing control knob  128  in one direction brings the guides closer together, and turning in the other direction moves the guides further apart. 
       FIGS. 15, 16, and 18  show several views of the adjustable drill guides  84 ,  86 . Each of the pair of adjustable drill guides  84 ,  86  ride on the spacing control shaft  224 , which is supported by the center divider  238 . A center divider recess  246  is formed along the inner edges of both drill guides  84 ,  86  each receiving a portion of the projecting center divider  238  when the drill guides  84 ,  86  are positioned to adjoin the center divider  238 . 
     A drill guide bore  252  extends downward through each of the pair of drill guides  84 ,  86 , with an elongate drill opening  256  formed in the front face of each of the drill guides  84 ,  86  to accommodate emergence of an angled drill bit  258  during formation of the pocket hole (see  FIGS. 14, 16, and 18 ). An enlarged bore  262  is formed in the upper portion of the drill guide bore  252  to receive a bushing  264  that protects the upper section of the drill guide bore  252  from such wear and impact damage as might otherwise occur during use of the step drill  114 . The bushing  264  rests upon an internal seat  266  formed at the base of the enlarged bore  262 , and a pair of setscrews  272 , received within a setscrew aperture  274  formed in the upper section of each of the drill guides  84 ,  86 , holds the bushing  264  in place within the enlarged bore  262 . 
     A network of ducts formed within each of the pair of adjustable drill guides  84 ,  86  routes the wood chips and dust generated by the drilling away from the step drill  114 . Initially, a tapered dust channel  282  formed in both drill guides  84 ,  86  opens from the drill guide bore  252  at a location adjacent to the elongate drill opening  256 . The tapered dust channel  282  provides a broadening taper to minimize clogging as the chips and dust move away from the elongate drill opening  256  and the angled drill bit  258 . 
     The wood debris from the drilling guides  84 ,  86  is received by a pair of dust evacuation channels  286  formed in the carriage  34  (see  FIGS. 19, 21, and 22 ). Each of the pair of evacuation channels  286  align with a separate one of the tapered dust channels  282  of the pair of drilling guides  84 ,  86 . A center divider slot  292  formed in the carriage  34  receives the center divider  238 , which assists in maintaining proper alignment of the drilling guides  84 ,  86 . The dust evacuation channels  286  convey wooden debris received from the tapered dust channels  282  into a debris chamber  296  that is formed inside of the carriage  34  and laterally extends across the rear portions thereof. 
     The shop vac connection  144  formed in one side of the carriage  34  enables the easy evacuation of accumulating chips and dust during drill operation. The large debris chamber  296  within the carriage  34  enables drill operation even without a shop vac, the accumulated chips and dust manually removed by the operator as needed during multiple drilling operations. 
     In a presently preferred embodiment shown in  FIG. 23  the vertical base  18  includes cavities formed therein for storage of the step  114  drill and a driver  298 . The storage cavity for the step drill supports the drill bit at the cavity bottom, permitting adjustment of shaft collar  132  location along the shaft without concern for drill shaft movement during such adjustment. Also shown in  FIG. 23  is a cavity  304  for storage of a side stop assembly  306  (see  FIGS. 27 and 28 ) and the square driver  298 . During use, the side stop assembly  306  is received within a side stop slot  308  formed in a lower edge of the vertical base member. 
       FIG. 29  illustrates the cooperative use of a lookup table  314  displayed on a side surface of the angled base member  28  with a carriage positional indicator  318  (shown as an arrow in  FIG. 29 ) inscribed on the side surface of the carriage  34  along the rear edge at a location that is adjacent to the side surface of the angled base member  28 . 
     Upon moving the carriage  34  along the front surface of the angled base  44  until the front surfaces  102 ,  104  of the pair of adjustable drill guides  84 ,  86  make contact with the workpiece  92  (not shown in  FIG. 29 ), the carriage positional indicator  318  will be positioned adjacent a table entry in the lookup table  314  identifying the workpiece thickness. Associated with such entry in the lookup table  314  is a recommendation of appropriate screw size (length) to use when making the pocket hole joint. In  FIG. 29  the carriage positional indicator  318  identifies the workpiece thickness as 1½ inches and recommends use of a screw length of 2 inches. 
     To further assist in the understanding of the nature and features of the present self-adjusting pocket hole jig invention, the following narrative and drawings provide an example of its use. A wooden workpiece is received within the pocket hole jig of  FIG. 1 , the workpiece is placed against the vertical base member and rests upon the horizontal base member. Where multiple pieces must be drilled alike, a side stop assembly is provided within the vertical base, enabling a user to easily place multiple workpieces at the same, fixed lateral position on the jig relative to the vertical base and to the drilling guides. For larger workpieces, a side stop is available. 
     The carriage is initially located at an upper position on the angled base. Rotation of the clamping knob loosens the clamp connection of the carriage and angled base, permitting movement of the carriage down the angled base until making contact with the front surface of the workpiece (see  FIG. 1 ). The clamping knob is rotated in a clockwise manner to secure the carriage/slide plate tightly in place against the angled base. Continued turning of the clamping knob moves the carriage forward, separating it from the slide plate and pressing it tightly against the workpiece. 
     The majority of pocket hole joints use two pocket holes and screws to assure a secure and square joint. Spacing between the two screws varies depending upon workpiece width (closer for narrow workpieces, further apart if wider). Adjustment is made to the left/right guide hole spacing using the spacing control knob to operate the spacing control shaft. Such spacing is symmetric to the jig centerline, and is easily adjusted and changed to fit the workpiece width. 
     Once adjusted, the step drill is mounted in a power drill and inserted through one of the elongated slots of the drill depth stop platform and then into the lower drill bushing until the drill tip rests on the angled side of the workpiece. The drill motor is activated, and drilling of the workpieces proceeds until the drill shaft collar contacts the drill stop platform. While still under power, the step drill is removed from the jig. 
     Normal drilling techniques are used during this process, including the raising of the drill bit every so often to permit any accumulated sawdust to clear from the pocket hole prior to reaching the hole bottom. The woodchips and dust generated by the drilling are conveyed through the dust channel formed in the drill guides, into and through the dust evacuation channels of the carriage, where it accumulates within the debris chamber until removal. 
     Upon completion of the two pocket holes the drill and step drill are removed from the drilling guide, the clamping knob rotated counterclockwise to first relieve the carriage pressure against the workpiece, and then permit movement of the carriage upwards and away from the workpiece along the angle base. 
     Removal of the workpiece follows, and the first workpiece  92   a  (with the pocket holes) is clamped to the second workpiece  92   b , as is shown using three examples in  FIGS. 24-26 . Pocket hole screws are placed at the bottom of the pocket holes, and a power drill and driver advance the screw through the remaining wood of the first workpiece and drive the screw into the second workpiece, forming the joint. 
       FIGS. 24-26  provide three examples of such joinery. In  FIG. 24  two 1½-inch workpieces are joined by two pocket holes (only one is shown), using two 2-inch long pocket hole screws. The screws extend 0.580 inch in the first workpiece and 1.40 inches into the second. In  FIG. 26  two ½-inch workpieces are joined, using 1-inch long pocket hole screws, extending 0.580 inch in the first workpiece and 0.420 inch in the second. In  FIG. 25  a 1-inch workpiece is joined to a 1-inch workpiece, using 1½-inch long pocket hole screws, extending ½-inch in the first workpiece and 1 inch in the second. 
     In a presently preferred example, and by way of example and not limitation, the following components are suitable for providing a self-adjusting pocket hole jig in accordance with the present invention. The jig base may be the 3-piece unit fabricated out of machined aluminum discussed above or the jig base may be implemented as a one or two-piece construction using machined, molded, or cast aluminum or other materials. Such alternative materials include, but are not limited to, cast zinc or non-deforming plastics, such as ABS (acrylonitrile butadiene styrene) plastic. 
     A suitably sized jig has a vertical base measuring 5.4 inches in length, 4 inches in width, and ¾-inch in thickness, a horizontal base measuring 4.16 inches in length, 4 inches in width, and ¾-inch in thickness, and an angle base measuring 4.62 inches in length, 4 inches in width, and 1⅛ inches in thickness. A slide channel in the angled base having measurements of 3 inches major width and approximately 2.75 inches minor width, over the angle base length of 4.62 inches is formed to receive a slide plate measuring 2.3 inches in length, 3 inches in width, and 0.67 inch in thickness. 
     A vertical slot formed in the rear surface of the angle base extends approximately 3¾ inches in length and is ½-inch width, receiving a threaded clamping shaft of 5/16 inches in diameter and 2 inches in length. A 5/16-18 hex nut (the only internally threaded component used in the assembly) with a dimension across the flats of ½-inch is loosely received by the clamping shaft. A closed end bore or aperture formed partway into the carriage has a depth of approximately 0.48 inches and a diameter just slightly larger than the 5/16 inch outside diameter of the clamping shaft. 
     A clamping adjustment knob attaches to an outer end of the clamping shaft; however, a cam-operated lever could also be used. In either case, a double-action securement occurs; first securing the slide plate from movement, and then the forward press of the carriage against the workpiece securely clamps the workpiece (see  FIGS. 4-8 ). 
     The carriage has four sides, none of them parallel. A base measures 1.905 inches, a rear surface 1.981 inches, a top surface 2.292 inches, with a width of 4 inches and a height at the front of 2.339 inches. The dust evacuation channels each consist of a cavity having a volume of approximately 0.04535 cubic inches, measuring approximately 0.27 inch in diameter at one end and approximately 0.316 inch in diameter at the other end, and a length of approximately 0.67 of an inch. The debris chamber approximates a cylinder having a 1-inch diameter and a length of 3⅞ inches, providing a volume of approximately 3.04 cubic inches. 
     The dovetail slides formed on the front face of the carriage measure 0.125 inch by 0.345 inch. As can be appreciated, other, similar slide technology may be used, such as square carriage slides, instead of dovetail slides, without departing from the scope and content of the present invention. 
     A pair of guide rods, each having a diameter of 0.375 inch and an approximate total length of 5.18 inches, guide the angled horizontal movement of the depth stop plate, with each of the guide rods received in a separate guide rod aperture formed in corresponding forward locations in the carriage. The guide rods are slidably attached to the horizontal base using flat head cap screws and a reduced lower rod end diameter. 
     Dust relief is provided at the underside of the horizontal base to facilitate removal of any buildup of sawdust that may occur. The rod end groove is a reduced diameter to seat the end of the guide rod to prevent movement in the downward direction. The upper end of each guide rod is received by the depth stop plate and fixedly attached by flat head screws. This manner of constraint enables the necessary range of motion of the guide rods, slightly more than one inch in the horizontal direction, while limited to a slip fit in the vertical direction. 
     In general measurement, the drilling guides have a height of 2.648 inches, a width of 1.365 inches, a depth at its base of 0.527 inches, and 1.194 inches at the top surface. The drill bushing has a 0.377 inch inside diameter, an outside diameter of 0.50 inch, and a length of 0.50 inch, and is received within an enlarged bore at the upper end of the drill guide bore. 
     Use of a hardened steel bushing enables fabrication of the remainder of the drilling guide out of a softer, plastic material, such as DELRIN® brand acetal resin or ABS plastic, with the possible exception of a hardened steel threaded liner for the spacing control shaft opening, which measures 0.250 inch in diameter and extends through each drilling guide. The spacing control shaft measures 0.25 inch in diameter and is approximately 4 inches in length. 
     The pocket hole angle provided by the present jig is 15 degrees. Although 15 degrees is considered somewhat of a standard angle for pocket holes, other angles can be obtained upon changing the carriage slide angle. In this regard, it has been determined that the ratio of the tangent of the carriage slide angle to the tangent of the drill angle must be an exact 2:1 ratio. For example, selection of 15 degrees for the drill angle requires the carriage slide angle to be the inverse tangent of twice the tangent of the drill angle—or 28.18 degrees. 
     My invention has been disclosed in terms of a preferred embodiment thereof, which provides a self-adjusting pocket hole jig that is of great novelty and utility. Various changes, modifications, and alterations in the teachings of the present invention may be contemplated by those skilled in the art without departing from the intended spirit and scope thereof. It is intended that the present invention encompass such changes and modifications.