Use a cordless drill/driver to remove the cabinet doors and hinges, then remove the shelves to get them out of the way (Image 1).
Remove the screws holding attached cabinets together. Support the weight of the cabinets and remove the screws through the cabinet back into the wall studs (Image 2).
Whether you change the height or width of a cabinet, you need to maintain its original symmetry. Measure carefully and remove equal amounts from both sides, or from top and bottom. Make the cuts on a table saw to ensure straight and square cuts.
Start by placing the cabinet face down on the saw. Cut through the face frame first, then flip the cabinet over and repeat these cuts through the back. Repeat the cuts on both sides.
Carefully trim away the excess wood from the cutoff pieces, cutting as close as possible to the original cabinet stiles or side rails. This will leave you with two ready-to-reassemble sides, or a top and bottom.
Use dowels, biscuits or screws with wood glue to reattach the cutoff pieces to the original cabinet box. Clamp the parts together while the glue dries.
The cabinets can be rehung after they are reassembled and the glue has dried, or you can install the new doors while they are still in the workshop.
Make a diagram of the new cabinets and carefully note each measurement (Image 1).
Measure the new cabinet openings and add 1-1/4” to each measurement. The cabinet doors shown here are full overlay, meaning they overlap the cabinet face frame on all sides of the opening (Image 2). The additional dimension allows for this overlap.
For double-doors, measure across both openings and cut one large piece of plywood to fit, then cut that piece down the middle to “bookmatch” the wood grain on the facing doors.
Cut the cabinet doors using the table saw for precise cuts. If you use a circular saw, turn each piece over and cut from the bottom side to avoid a ragged edge on the wood face.
Finish the plywood door edges with pre-glued wood veneer tape. Use an ordinary clothes iron to activate the adhesive.
Baltic birch plywood provides a good painting surface, if you wish to match your original cabinets, or it may be stained without first using a wood conditioner. For a natural-wood look, simply apply three coats of non-yellowing polyurethane sealer to the doors.
European-style cup hinges are recommended for full overlay cabinet doors, and they are superior in many ways to simple butt hinges (Image 1). For example, they are adjustable after installation, so if the doors don’t line up correctly you can easily change the height, angle and closing depth of the door. Installation systems are available for these hinges and include boring templates and Forstner-type drill bits for precise hinge placement.
Use a square to measure and mark hinge locations (Image 2). Install the hinges on the doors first, using a self-centering drill bit.
Determine which door will be hung in each opening, then install the doors one at a time, using each door’s hinges as a template. Add knobs and hang new cabinet doors (Image 3).