Measure the length and width of the front of the cabinet. Cut out a piece of 1/2-inch thick knotty pine wood to the same measurements using a circular saw.
Sand the entire board using medium-grit sandpaper to remove any splintering or roughness. Sand the board again using fine-grit sandpaper to make the wood smooth and soft.
Brush off the board using a 2-inch flat paintbrush to remove any sawdust.
Stain the entire surface of the knotty pine board in an even layer using wood stain and a sponge paintbrush. Allow the stain to dry for six to eight hours.
Apply an even layer of clear latex varnish over the entire surface of the board using a 2-inch flat paintbrush. Allow the varnish to dry for six to eight hours.
Place a cabinet handle onto the front of the cabinet along the right side, and mark the screw holes with a pencil. Remove the handle.
Drill into the marked spots using a drill with a 1/8-inch drill bit. Place the handle back into place, lining up the holes, and then insert the screws into the holes using a screwdriver to attach the handle to the knotty pine board.
Place two hinges along one side of the board, spacing them out evenly. Mark into the screw holes with a pencil to mark where to drill the holes. Remove the hinges.
Drill into each marked hole using a drill with a 1/8-inch drill bit.
Place the hinges back onto the board, and then insert the screws using a screwdriver to secure the hinges in place.
Position the board onto the front of the cabinet, and fold over the hinges. Mark with a pencil inside of the holes onto the cabinet to show where to drill.
Remove the board, and drill into the marked places using the drill with a 1/8-inch drill bit.
Position the board back into place, and insert the screws into the hinges on the cabinet using a screwdriver to secure the knotty pine cabinet door in place.