Measure the length of the cabinets and the depth from the front of the cabinets to the wall in areas where cabinet ends are exposed. Some cabinets are installed from one wall to another, while others may have one or both ends exposed, most often at a window or walkway.
Transfer the cabinet length measurement to a 1-by-2-inch wood furring strip and cut it straight across with a hand saw or miter saw.
Attach the furring strip to the top of the cabinets, along the front top edge, with finishing nails about every four to six inches. Ensure the furring strip sits flush with the front of the cabinet.
Measure the width of the furring strip attached to the front edge of the cabinets. Subtract the furring width measurement from the cabinet depth measurement, and cut a piece of furring strip to fit the top depth of the cabinet at the exposed end. Attach the furring strip to the top of the exposed end cabinet.
Cut a small 2- or 3-inch long piece of crown molding and mark its face with an arrow pointing to the top of the molding. Use this piece as a reference when cutting molding to ensure you orient it correctly, with the top of the molding pointing up, when making miter cuts.
Make straight, 90-degree cuts on each end of the molding if the cabinets rest between two walls. This installation does not require miter cuts.
Attach the molding to the top of the cabinet at the furring strip. Drive finishing nails through the bottom edge of the molding and into the furring strip about every four to six inches.
Measure the length of the cabinets once again to ensure the figure is correct before mitering the ends of the molding to install it around the outside corners of the end cabinets.
Cut the ends of the molding for right-side corners by rotating the miter saw to cut at a 45-degree angle to the left, lining up the measurement mark at the blade. Orient the molding against the wall of the miter saw with the top facing up. Look at the reference piece to ensure you properly positioned the molding.
Make left-side corners by rotating the miter saw to cut at a 45-degree angle to the right.
Reverse the angles for inside corner cuts. To cut the left side; rotate the miter 45-degrees to the left. For the right side, rotate the miter 45-degrees to the right.
Attach the molding to the furring strip beginning at one end of the cabinets by applying wood glue to the mitered corner edges. Attach each additional piece of molding until you crown each cabinet.
Nail the two ends of molding together on outside corners. Drive one finishing nail through both pieces of molding at the top and drive another through both pieces at the bottom. This reduces the gap between two pieces of molding on outside corners. Position a metal countersink on the head of each finishing nail, and strike the countersink with a hammer to countersink each nail in the molding.
Apply wood putty to any gaps between the molding pieces and to the countersunk nails and allow the putty to dry.
Sand the dried wood putty with fine-grit sandpaper. Paint or stain the crown molding to match the kitchen cabinets.