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Use a flat (raised panel) door for a quality look. Change the bit to a coping or stick bit. Determine the dimensions of the panel. Purchase rubber space balls, available at most woodworking supply stores. Apply glue to the tenon of the rails. Sand the door, finish as desired.

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You need to realize that this type of cabinet door requires more tools, skill and time to create. However, the finished results can be very rewarding if you are willing and ready to step up to the challenge. Panel doors consist of two stiles (side pieces) and two rails (top and bottom) along with a panel that sits between them.  Cut the stiles and the rails from 4/4 (2.54 cm) material - if you can - and mill or plane down the material to a consistent width of .75 inches (2 cm). Accuracy and consistency of width assures a good fit. The rails need to be approximately .5 inches (1.2 cm) less than the stiles. The width depends on the project and the look you want for your cabinets. Make the stiles blanks the length you need and then run the inside edge through a stile router bit mounted on a router table.    {"smallUrl":"https:\/\/www.wikihow.com\/images\/thumb\/b\/b4\/Make-Cabinet-Doors-Step-4Bullet3.jpg\/v4-460px-Make-Cabinet-Doors-Step-4Bullet3.jpg","bigUrl":"\/images\/thumb\/b\/b4\/Make-Cabinet-Doors-Step-4Bullet3.jpg\/aid1199888-v4-728px-Make-Cabinet-Doors-Step-4Bullet3.jpg","smallWidth":460,"smallHeight":345,"bigWidth":"728","bigHeight":"546","licensing":"<div class=\"mw-parser-output\"><p>License: <a rel=\"nofollow\" class=\"external text\" href=\"https:\/\/creativecommons.org\/licenses\/by-nc-sa\/3.0\/\">Creative Commons<\/a><br>\n<\/p><p><br \/>\n<\/p><\/div>"}  Cut the rails to the length you need. Determine this length by measuring from the outside edge of the stiles to the beginning of the round-over, or bead, you made with the router bit. Subtract this from the width of the opening, then cut the rail blanks to length. Run the inside edge through the router using the same bit you used earlier. The coping bit creates a secure and tight fit of the rail to the stile. Now, run the ends of the rails through the bit. Measure from the outside edges to the beginning of the rollover (or bead). Subtract that distance from the total height and width of the door. A flat door panel will usually be made from .25-inch (.6 mm) plywood - the same wood type as the rest of the cabinet.  Cut the door panel insert slightly less than the size you need to allow for wood expansion and contraction. Ordinarily, this will be the width of a table saw blade.  Begin assembly of the door. Apply glue with a brush to the inside of the stile where the rail meets it and insert the rail tenon. Place the balls into the groove you created with the router style bit. Insert the panel. Slide the second stile into place. Clamp the pieces together, and allow the glue to dry. Install the hardware and hang the new cabinet door on the cabinet frame.