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FIELD OF THE INVENTION 
     The current invention pertains to new and useful improvements to a door assembly process utilizing mortises, tenons and dowels as well as use of dowels for locking door stiles and rails. 
     BACKGROUND OF THE INVENTION 
     Millions of doors are assembled, installed and renovated every year. The process of manufacturing and assembling door is long and complicated; usually it takes several hours to assemble and install a door. Generally, the door is supplied as fully assembled with or without a frame. If the door is supplied without a frame, then prior to installation, the hinges and locks have to be drilled, cut and attached to the door and the frame. Generally, most of the doors have to be prepped for hardware prior to installations; this procedure requires a manipulation of a heavy door. 
     The manufacturing process requires that the door assembly be glued to keep the parts together, and during the gluing process the door has to be locked in special clamps to keep its integrity. The glue requires an extensive curing time before the rest of the door assembly can be completed. Following the gluing process, the door stiles have to be beveled in order to allow smooth closure of the door. The beveling process is known in the art and involves a removal of some layer(s) of material from the stiles on the hinge and/or lock side, thus creating a vertical plane with a slope of approximately 2-3 Degrees. Only after beveling can the whole door be sanded, prepped and painted or covered by protective layers known in the art. 
     This lengthy and involved door manufacturing process allows delivery of fully assembled doors. Delivery of doors in a disassembled state is not possible as the gluing and beveling process can only be performed on site. Furthermore, in the current process if a part or parts of the door are damaged during transportation, the entire door is considered broken and must be replaced. 
     In the case of a modular door, only the damaged part needs to be replaced. 
     The delivery of disassembled doors has the following benefits: they take less space, the risk of breakage is reduced, and if there are broken parts, they can be easily replaced by spare parts. However, disassembled doors need to be assembled on-site by the end user. Therefore, a kit for door assembly is required in which the stiles are beveled prior to the assembly. The assembly kit does not require any complicated tools and ordinarily does not require use of glue. 
     One of the technologies used in door building and manufacturing is the use of mortise and tenon. This technology is well-known and described for example, in U.S. Pat. No. 0,541,450. This patent teaches a door comprising styles and rails, which are suitably mortised and tenoned together while dowel pins are inserted into the long side of the stiles and pass through both tenons while remaining invisible. This locking means is generally used to improve sturdiness of the final product but does not eliminate the use of glue during the door assembly. There is a further technology of mortise and tenon with protruding dowel also disclosed in the U.S. Pat. No. 5,086,601. This Patent teaches a construction of frames for windows and doors while utilizing a joint structure with mortise and tenon. 
     The present invention addresses the deficiencies in prior art by providing an improved method of door assembly by reducing or virtually eliminating a use of glue. The invention also provides a kit for self-assembly of a modular door and method of manufacturing such kit. 
     SUMMARY OF THE INVENTION 
     The current invention pertains to new and useful improvements to a door assembly process utilizing mortises, tenons and dowels as well as use of dowels for locking door stiles and rails. 
     The primary aspect of the invention is to bevel and prep the hardware during the manufacturing process in such a way as to give the end user the ability to assemble a door without the use of glue or a door clamp press. The elimination of glue allows disassembly of the door if needed. 
     The glue-less construction of the door creates multiple advantages and options of improving the design, style, workability, integrity, reuse, and repair if needed as the process allows the end user to take the door apart after it has been assembled, resulting in a considerable savings in time and money by placing the customization factor into the users&#39; hands. 
     The crux of the assembly is using a traditional mortise and tenon joint in the door assembly. In its preferred embodiment, a hole is created within the tenons on the rail at both ends while a slot is created along the entire body of the stile. This slot stops short of the mortises at the top and bottom of the stile. Thereafter, an oversized hole is drilled in the stile for accommodating the bushing. The bushing completes the slot, by retaining integrity of the stile and enabling rods to be pre-inserted without added friction. This function is useful during assembling or disassembling multiple rail configurations. 
     Preferably, the corresponding holes in the tenons and slots are slightly off-set to one another. In this way, when assembled the stiles and rails in combination with the dowel/bushings being driven into their final resting position create an opposing force so all mortise and tenons are pressed and locked together for all stiles and rails simultaneously. Finally, driving a screw through the bushing into the rail and/or stile locks the bushings and dowels in place. 
     If conforming to the teachings of the prior art, the door is usually assembled with glue and then placed into a clamp door press. Other necessary steps include pressing the joints, squeezing out the excess glue and waiting for the glue to cure. Once the glue has cured the door is removed, then beveled, and prepared for hardware installation. 
     In some applications in the prior art, the mortise and tenon are drilled once the door is fully assembled. This is done at the top and bottom railings of the door. The dowel is inserted to act only to keep the parts together; it is not used to close a gap between parts. Finally, in the prior art the mortise and tenon combination are used only on the top and bottom rails. The current invention allows to use locked mortise and tenon at the intermediate rails as well. 
     The current invention eliminates the use of glue and the use of a door clamp press, which has a direct result of eliminating the curing time, beveling and prepping for hardware after the assembly for the end user. 
     Beveling and prepping for hardware is done during the stile manufacturing process. The manufacturing process dictates the use of a clamp press with two parallel surfaces in order to prevent buckling and deformation of the door under force. 
     If needed, the stile can be matched to an existing opening, transcribing the original hardware placement to the new door or in this case stile. Since the single stile can be handled, the marking of the hardware makes this a much easier task to handle in place of a fully assembled door. After prepping the stile, the door can be assembled and immediately installed without a wait for glue curing and other door preparations utilized in prior art. 
     Another aspect of the invention is a use of extensions to the rails of the door. These extensions can be used on the top and/or bottom rails. The end user&#39;s choice of different materials such as wood, metal, Plexiglas, plastic or composite material extension will give the door a unique look. In addition, use of extensions can make it more resilient to the elements. Using a rubber or silicon cover on the extension may, for example, assist in reduction of water damage to the door. Furthermore, use of extensions would allow replacement of the extension only if it became soiled or broken, without need to replace the whole door. 
     According to one aspect of the invention there is provided a modular door having:
         a. two pre-manufactured stiles having two ends and two sides, and provided with mortises along one of the sides and a rod receiving slots passing through said mortises   b. a top and a bottom pre-manufactured rail having two sides and two ends with tenon provided at each end while each tenon has a predrilled aperture to receive locking rod,   c. while the stiles and rails are enclosing at least one door panel,   d. at least one intermediate rail having tenons, positioned between the top rail and the bottom rail;   e. The said rails are attached to the first and second stiles by the means of mortises and tenons fastened in place by a set of rods.   f. Said set of rods comprises: locking rods of sufficient length to lock a single rail or a plurality of rails inside the corresponding stile. Said modular door can be assembled by insertion of the tenons of the rails into the corresponding mortises of the stiles followed by locking in place with the set of rods.       

     Preferably, each stile of the door comprises a slot for receiving rods. This slot extends from the top of the stile to the bottom of the stile passing through the mortises of the stile. 
     Preferably, the tenons of the rails have pre-drilled apertures to receive the locking rods, and upon insertion of each tenon into the corresponding mortise of each stile the rod receiving slot and aperture are position in an offset to one another. Thus, upon insertion of the locking rod, each tenon is tightly locked into its corresponding mortise. 
     In a preferred embodiment, the set of rods comprises pushing rods, locking rods, and locking/pushing rods. The pushing rods are provided to deliver the locking rods into the tenons of the intermediate rail, while the locking/pushing rods are provided to lock one rail as well as to push another locking or pushing rod through the rod receiving channel of the stile. 
     According to yet another aspect of the invention, the set of rods further comprises an unlocking rod having the length equal to the height of the tenon of the corresponding rail to be unlocked. These unlocking rods are positioned between the pushing rods and the locking rods, and can be pushed into the tenon of the rail while removing the locking rod from the tenon to release the intermediate rail from the stile. 
     According to yet another aspect of the invention the top and/or bottom rails include a receiving member to receive an extension to the door with a corresponding mating member. This extension to the door can be decorative or functional and can be easily replaced upon wear or change in utility. 
     According to one additional aspect of the invention, there is a kit for assembling a modular door comprising:
         a. two pre-manufactured stiles having two ends and two sides, provided with mortises along one of the sides and a rod receiving slots passing through said mortises;   b. at least three pre-manufactured rails having two sides and two ends with tenon provided at each end while each tenon has a predrilled aperture to receive locking rod;   c. at least one door panel; and   d. a set of rods to lock the rails to the stiles.       

     The set of rods should include two short locking rods of sufficient length to lock one rail to the stile and two long locking rods of sufficient length to lock at least two rails to the stile. More preferably, the set of rods has at least six locking rods to lock at least three rails to the stiles, and at least two pushing rods to deliver the locking rods into the distant mortises of the stile. Still more preferably, each stile has at least one locking rod, one pushing rod pre-inserted into its rod receiving slot proximate mortise, distant from one of the ends of the stile. 
     In yet another embodiment there will be an unlocking rod further positioned between the pre-inserted locking rod and pushing rod and a filler rod holding these rods in place during storage and delivery. 
     Preferably the kit also has at least one door extension member capable of being attached to at least one of the rails. 
     According to still another aspect of the invention there is provided a method of assembling a modular door comprising stiles with mortises, and rails with tenons, by the means of rods. 
     The method comprises insertion of the tenons of the rails into the mortises of the stiles followed by insertion of the rods into rod receiving slots of the stiles and apertures of the tenons, thus locking the rails inside the stiles. In a preferred embodiment at least one door panel is positioned between the rails and the stiles. Preferably two or more door panels are positioned between these rails and stiles. 
     The rods locking the rails inside each stile comprise at least one rod, and preferably more than two rods. The rods are selected from locking rods, pushing rods, filler rods, unlocking rods and combinations thereof. 
     According to yet another aspect of the invention, there is provided a method of assembling a modular door with at least two stiles with mortises and at least three rails with tenons, using rods. While the order of the steps can vary, the method has the following steps:
         1. Insertion of a tenon of a first rail into the first mortise of the first stile;   2. Locking said tenon in said mortise with a first dowel or set of rods;   3. Positioning a first door panel adjoining said first rail and first stile;   4. Insertion of a tenon of a second rail in to the second mortise of the first stile while locking the first door panel in place;   5. Positioning a second door panel adjoining said second rail and the first stile;   6. Insertion of a tenon of a third rail into the third mortise of the first stile while locking the second door panel in place;   7. Locking the tenons of the second and the third rails in corresponding mortises by a set of rods;   8. Positioning the second stile on the side of the rails distant from the first stile, wherein the tenons of the rails are inserted into the corresponding mortises of the second rail and the first and second door panels are also locked in place; and   9. Locking the tenons of the rails in the second stile by the set of rods.       

     The assembled door does not require a use of glue or additional bonding agents during the assembly process. 
     The set of rods locking the rails inside each stile comprise at least one rod, and preferably more than two rods. The rods are selected from locking rods, pushing rods, filler rods, unlocking rods and combination thereof. Preferably, a set of bushings further locks the rods inside the stiles. 
     Additionally, the use of Plexiglas gives an even broader choice of uniqueness by shining light directly on to the Plexiglas and using it as a light conductor through the door body to shine out the other end without the use of wires. 
     Another aspect of the invention is the ability to take the door apart. Disassembly of the door brings a unique factor into effect. If a door is to be disassembled due to the size being increased, design change, and/or a damaged component in the door that needs replacing, these tasks may be done easily. 
     The end user can accomplish the above-named tasks by removing the screw penetrating the rail and bushing and, using the same screw, drive into the center of the bushing through the dowel leaving half the screw outside of the bushing. This will lock the bushing to the dowel. Using this as a clamping point, the rods that hold the tenons can be unlocked by simply removing the bushing/dowel at either ends of the door. Once completed, a rod of smaller diameter may be inserted. The length is determined by the following formula:
 
width of the tenon+plus length of bushing/dowel that was removed+one inch
 
     The rod is then inserted into the door with force needed until the tip is flush with the door. Remove the rod and repeat this procedure for all the locks. The rails are unlocked from the stiles; the door can now be disassembled. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         FIG. 1  is an exploded view of the modular door. 
         FIG. 2  is a see-through view of an assembled modular door. 
         FIG. 3  is an elevated see-through view of a rail of the modular door. 
         FIG. 4  is an elevated view of a stile. 
         FIG. 5  is a cut view of  FIG. 4  through line A-A. 
         FIG. 6  is an enlarged top view of area B of  FIG. 5 . 
         FIG. 7  is an elevated view of the extension insert into the rails. 
         FIG. 8  is see through partial view of the bottom part of the assembled door. 
         FIG. 9  is an elevated view of the bushing. 
         FIG. 10  is a cut view of  FIG. 9  through line C-C. 
         FIGS. 11-15  illustrate the process of disassembly of the modular door. 
         FIG. 16  is an illustration of stile with pre-inserted rods. 
         FIGS. 17A and 17B  demonstrate the interaction of the rail and stile in locked and unlocked state. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       FIG. 1  illustrates an exploded view of the modular door  10 . This modular door comprises a first stile  20 , a second stile  21  and a minimum of a top rail  30  and a bottom rail  32 . The door should also comprise at least one intermediate rail  31 . Depending on the design requirements, the door may include additional horizontal rails between the top and bottom rails  30  and  32 . Locked between the stiles and the rails, there are panels  11  and  12 . The panels can be manufactured any way and from any material known to a person skilled in the art of door manufacturing, and the number of panels may vary according to the number of rails. 
     Each stile comprises a plurality of mortises corresponding to a set of tenons positioned on the rails, best illustrated in  FIG. 2 , and there is a set of pins or dowels ( 40 - 44  and  46 ), which retain the tenons inside the mortises of each stile. 
       FIG. 2  illustrates rail  31  with tenon  34  positioned proximate to its corresponding mortise  26  in the stile  21  and rail  32 , with tenon  34  positioned proximate to its corresponding mortise  25  in the stile  21  prior to the assembly process. 
       FIG. 2  illustrates the assembled door while the tenon  34  of rail  31  is completely inserted into the mortise  26  of stile  20  and locked in this position by the means of the dowel  40 . Tenon  34  of rail  32  is fully inserted into the mortise  25  of stile  20  and locked in this position by the means of the dowel  44 . Finally, tenon  34  of rail  30  is fully inserted into the mortise  27  of the stile  20  and locked in its position by the dowel  46 . Rails  30 ,  31  and  32  are fixed to the stile  21  on the opposite side of the door, in the same manner as they are fixed to the stile  20 . 
     As illustrated in  FIG. 2 , panel  11  is locked between rails  30  and  31  and by stiles  20  and  21 , while panel  12  is locked between the stiles  20  and  21  and rails  31  and  32 . 
     Manufacturing Process of Rail: see  FIG. 3 
         1. Rail  30  is squared.   2. Groove  36  is cut vertically on one side of rail  32  down the center of the rail so a panel  11  can be inserted into this groove during the door assembly.   3. The pair of tenons  34  is created on each end of the rail  32 .   4. Protrusions  35  are drilled in each tenon. These protrusions receive the dowels locking them inside the mortises of the stiles.   5. In one of the embodiments, top rail  30  and/or bottom rail  32  may have an extra mortise  33  on a side opposite the groove  36  in order to receive an extension  37 . In yet another alternative embodiment the bottom rail  32  can also have a mortise  33  to receive a bottom extension  37 . All the intermediate rails  31  have two grooves  36  to receive the panels on both sides.   6. Preferably a chamfer is applied to the tenon for better seating on assembly of the door.       

     In one embodiment, the bottom rail  32  and top rail  30  are identical and can be used interchangeably to reduce the number of manufactured pieces of the door. In yet another embodiment (not shown), rails  30 ,  31  and  32  may be identical thus the groove  36  on both sides of the rail can be used to receive a panel  12  or extension  37 . 
     Referring to  FIG. 7 , extension  37  to the door can be added to the top rail  30 , bottom rail  32  or both by the means of insertion a mating member  38  into the receiving member  33  of the rails. The mating member  38  can be of any type known in the art such a ridge, tenon, and a plurality of pins, etc. 
     The extensions can vary in height, preferably from ¾″ to 10″ dependent on the manufacturing materials and design. Extension  37  can be constructed from various materials such as metals, wood, plastics and composite materials. Each extension  37  can be rubberized, painted or coated to protect the insert from elements and wear. 
     Manufacturing Process of Stile Refereeing to  FIGS. 4-6 : 
     The manufacturing process of stile  20  is similar to the manufacturing process of the stile  21 . The only difference is the preparation and positioning of the hardware on these stiles.
     1. The stile  20  is squared and beveled. This is different from the existing assembly technology, where beveling is done after the door assembly.   2. A number of mortises including 25, 26, 27 and others, are cut into stile  20  according to design.   3. Groove  22  is cut down the center of stile  20  (opposite the bevel) so panels  11  and  12  can be inserted during an assembly process.   4. Slot  23  is provided down the center of the stile just short of the top and bottom keeping the integrity intact. This slot would receive rods/dowels, locking the tenons of the rails in the mortises of the stile. The slot  23  can be lined (not shown) with a plastic or metal sleeve in lieu of the wood. Slot  23  is placed a few millimeters behind groove  22  that holds the panels  11  and  12  in place in order not to lose the integrity of the groove  22 .   5. Bushing holes  28  are drilled at the top and bottom of stile  20  continuing where the slots left off to accept a wood, plastic, Plexiglas or metal bushing/dowel.   6. In a preferred embodiment Illustrated in  FIG. 16 , at least some of the rods  40 ,  41 ,  42  and  43  are strategically pre-inserted into the slot  23  to save on assembly time of the finished door for the end user.
       The rods/dowels have varied lengths, two of which are of smaller diameter and can be made of wood, plastic, Plexiglas, metal or other material known in the art. The length of the first rod  40  (locking rod) is the tenon  34  width plus two inches.   The second rod  41  (pusher/unlocking rod) has the width of the tenon  34  and a smaller diameter than rod  40 .   The third rod  42  (pusher rod) is a few inches short of the following mortise, as well as being of smaller diameter, and the final rod  43  (filler rod) will fill the remaining gap to the edge of the mortise has the same diameter as the slot.   The lengths of the rods/dowels are determined by the design. If using multiple rails  31  and if locking from one side top or bottom, approximately 2 inches or the width of the tenon should be added to the locking rod  41  for every rail added.   
       7. As illustrated in  FIG. 16 , the first rod/pin/dowel  40  which will be referred to as the “locking rod” will be placed at the very edge of the center mortise  26 . It will enter from the bottom or top of the stile from which a hole was created to accept a bushing (depending on design multiple mortises). Once it has entered the slot a small amount of force should be applied in order to bring it into place.
       The second rod  41  “pusher/unlocking rod” will enter from the following mortise and be placed behind the first rod. Little to no force will be needed to position this rod, as this rod has a smaller diameter than the locking rods. The third “pusher rod”  42  will also use the same path as the first rod  40  and be placed directly against the unlocking rod  41 . Little to no force will be needed to position this rod, as it too has a smaller diameter than the locking rod. The fourth and final filler rod”  43  will be placed against the pusher rod and enter from the mortise like the second rod (short in length). This filler rod is provided in order to keep all the pre-inserted rods in place during the transportation. A small amount of force will be needed to position this filler rod  44 .   This may all be repeated depending on the design chosen.   
       

     Dowels/rods/pins  40 ,  41 ,  42 ,  43 ,  44 ,  46  are provided to lock the tenon inside the mortise, and to move the neighboring dowels into correct positions. Dowels will vary in diameter ¼″ to 1″. The material of the dowel will vary according to the design, size and weight of the door. The material can be selected from metals (such as steel or metal alloys), wood species, Plexiglas, plastics, etc. 
     According to yet another aspect of the invention, one long rod may replace all the rods  40 - 44 , and this long rod may lock both rails  31  and  32  to the stile  20 . 
       FIG. 9  provides an illustration of bushing  45 . The bushing  45  as well as bushing  47  in  FIG. 1 , is provided to lock the pins/dowels in their position and to prevent movement of the dowels away from slot  23 . 
     Bushing size will vary in length and diameter in lengths of 1″ to 3″ and diameters of ½″ to 1⅝″. The material of the bushing can be selected from metals such as steel or metal alloys, wood species, clear or colored Plexiglas, plastics, etc. In one preferred embodiment the bushing  45  is coupled with the bottom rail locking rod  44 . This rod can be locked in the seat  55  (see  FIG. 10 ) by any means known in the art. In addition, the bushing  45  has a tapered screw hole  48  allowing the bushing to be locked both to the stile  20  and rail  30 . 
     In the same manner the bushing  47  may be coupled with the top locking rod  46 . 
       FIGS. 17A and 17  B 
     In a preferred embodiment, the protrusions  35  in the tenons  34  are created in an offset from the center line of the slot  23  of the stile  20 , thus creating a pre-tensioned joint. This is done in order to create a pulling force on the tenons  34  into their corresponding mortises when the rods/dowels are inserted. This force therefore, closes the gap G between the two components (the gap G in  FIG. 17B  is smaller than the gap G in  FIG. 17A ). This force causes a tight attachment between the components and therefore eliminates the need of using a clamp press for gluing the door. Further, it virtually eliminates the use of glue in the door assembly process, making the process simpler, faster and economically effective. 
     Process of Assembly: see  FIG. 1 . 
     An example of the modular door assembly process is provided below. 
     In one of the embodiments, mortises, tenons, channels and dowels can be sprayed or covered with substances known in the art, to allow smooth insertions of tenons and dowels.
     1. Stile  20  is positioned on a flat surface.   2. Top rail  30  is attached to the top of stile  20  with tenon  34  inserted into the mortise  27 .   3. Dowel  46  is inserted with the appropriate force into its final resting position generating a force from the offset created in the manufacturing process to close the gap between the stile  20  and rail  30  and locking it into position.   4. Bushing  47  locks dowel  46  followed by driving a screw in an angle through the bushing  47  into the rail  30 , locking the bushing to the stile  20  and rail  34  simultaneously. In a preferable embodiment the bushing  47  is coupled with the dowel  46  prior to insertion into the slot  28  to make the process of assembly more convenient and reducing the chance of damaging the dowel.   5. Insert panel  11  or panels if required by design into the panel grooves  36  and  22 .   6. Insert the middle rail  31  and or multiple rails into the stile  20  (if required by design) by insertion of the tenon  34  into mortise  26 .   7. Insert panel  12  (or panels if required by design) into the panel grooves  36  and  22 .   8. Insert bottom rail  32  into the stile  20  by insertion of the tenon  34  into mortise  25 .   9. Insert bottom bushing/dowel  44  with the appropriate force into its position, while at the same time pushing the pre-inserted rods  40 ,  41 ,  42  and  43  into their final resting position. This will generate force from the offset closing the gap between stile  20  and both the middle rail  31  and bottom rail  32  simultaneously.
       Then drive a screw into the bushing  45 , locking the bushing to rail  32  and stile  20 .   
       10. Place stile  21  in is corresponding position and apply force bringing the stile down to its final seating, mating the tenon  34  of rail  30  with mortise  27 , tenon  34  of rail  32  with mortise  26  a and tenon  34  of rail  32  with mortise  25 .   11. Insert dowel  46  with the appropriate force into its final resting position generating force from the offset created in the manufacturing process to close the gap between stile  21  and rail  30  and locking it into position. Lock the dowel  46  with bushing  47 , then drive a screw into the bushing  47  to connect it to the rail  30  and stile  21 . (Preferably bushing  47  is coupled with dowel  46  as explained above.)   12. Finally, install dowel  44  with the appropriate force into its final resting position, while at the same time pushing the pre-inserted rods  40 - 43  into their final resting position, which will generate force from the offset to close the gap between both stile  21  and the mid and bottom rails  31  and  32  (and/or multiple rails) simultaneously.
       Lock the dowel with bushing  45 ; drive a screw into bushing  45  to lock the rail  32  to the stile  21 . (Preferably the bushing  45  is coupled with the dowel  44  as mentioned above.)   
       

     Alternatively, in a further embodiment of the invention, glue or another bonding agent can be added to all mortises and tenons to add strength to the door, if the door will not be disassembled. However, this addition of glue prior to assembly does not extend the assembly time since there is no need to wait for the glue to dry. 
     Process of Disassembly:  FIGS. 11-15   
     There may come a time when a modular door may need to be disassembled to replace worn or damaged parts. If glue was not utilized during the assembly, disassembly is relatively easy. 
     Steps for the full disassembly of the modular door are provided below; but in most cases, a partial disassembly of the door will suffice.
     1. Remove the screw locking the bushings to rail and stile. (See  FIG. 11 .)   2. Drive a screw through the center of the bushing into the dowel, locking dowel and bushing together. A good portion of the screw should be left protruding so that it can be used as an anchoring point for the bushing and dowel to be removed (See  FIG. 12 .)   3. Use the claw end of a hammer or other tool known in the art; remove the bushing and dowel attached by the screw, using a technique known to a person skilled in the art.   4. Repeat the above procedure with all bushings.   5. Using a rod  50 , (preferably made of steel, with a substantially smaller diameter and having sufficient length to push the unlocking dowel  41  into the tenon  34  of the rail  31 ) remove the locking dowel  40  from the tenon  34  of the rail  31 . Place it into the hole and drive it forward until the tip is flush with the edge of the door (see  FIG. 15 ).   6. Rod  50  is then removed from the slot using tools known in the art. The rod  50  used to push the dowels may vary in length due to design.   7. The door can now be taken apart. The mortise and tenons are unlocked.   

     Advantages of the Modular Door Kit
     1. Before assembly the stile can be machined for hardware installations such as hinges and or locks. A single stile simplifies handling, unlike manipulating the entire assembled door.   2. Shipping the components in a disassembled state makes the process of loading/unloading from dock level, truck, or condo elevator much easier to manage.   3. This novel process gives the customer on-the-spot flexibility in design, dimensions and integrity with multiple choices of materials and designs that can be used. For example, pre-manufactured parts of the door (such as the door panels) can be constructed from different materials to fit the custom design selected by the end user at the store.   4. This vast customization factor eliminates delays and reduces material and labour costs that are incurred as a matter of course when manufacturing custom doors.   5. After assembly is complete, the door can be installed immediately whether an end user chooses to assemble it with or without glue.   6. Do-it-yourself end users have the opportunity to assemble the door themselves, thus furthering labour cost savings.   7. The pockets  36  created on the top and bottom of the door rails provide the customer with an option of extending the height of a door to match high door openings, allowing an existing door to be reused rather than replaced. Depending on the chosen material, inserts  37  can make the door more resistant to the elements, increase its integrity or simply bring about a design change.   8. In a preferred embodiment, when the door is assembled without a bonding agent, the end user has the advantage of greater flexibility in design, dimensions, replacement of damaged components, or even disassembly that was not previously available.   

     In one of the alternative embodiments, by using a Plexiglas or other transparent material in bushing/dowel and rods the door can be illuminated. A light source can be placed on either the top or bottom of the door and, using the Plexiglas as a conductor to carry light through the door can create a unique look without the need to run any wires through the door. 
     Design options may include choosing transparent, semi-transparent, or light scattering features on selected parts of the door. For example, an illumination from the sill of the door can be transferred through hard transparent dowels to similarly constructed top and/or bottom rails, providing such a door with a unique illuminating feature. The transparent or otherwise light scattering inserts can be positioned in the rails, panels and even stiles. 
     The embodiments provided above are presented in an illustrative, not limiting way. Many changes and variations can be made to the embodiments without departing from the scope of the invention. 
     As many changes can be made to the preferred embodiment of the invention without departing from the scope thereof; it is intended that all matter contained herein be considered illustrative of the invention and not in a limiting sense.

Summary:
The invention pertains to a technology of manufacturing and assembling modular doors, which can be assembled on site, and specifically to modular doors, which can be assembled without a use of glue, by mortize and tenons.