Gaps Less Than 1/4 Inch
Step 1
Drill evenly space holes through the interior of the cabinets on either side of the gap, roughly 6 inches apart, 2 inches from the front of the cabinets. Use a drill bit with a smaller diameter than the 3/4-inch wood screws.
Step 2
Slide a washer over each wood screw, and drill wood screws into each of the predrilled holes. Begin at one end of the cabinet and work your way to the other. Tighten the screws completely until the gap decreases and the screw is at surface level inside the cabinet.
Step 3
Re-tighten the previously installed screws once the final screw is in place. Add additional screws if necessary to further decrease the gap between the cabinets.
Gaps Wider Than 1/4 Inch
Step 1
Measure the vertical distance the trim board must cover, and mark that distance on the trim board. Cut the trim board to fit with the saw.
Step 2
Measure the horizontal distance the trim board must cover from the storage side of each cabinet edge. Transfer the distance to the trim board, and cut the trim board with the saw or utility knife so its horizontal size matches the necessary coverage.
Step 3
Position the trim board in its intended location, and fasten it in place by hammering in finishing nails every 6 inches along both cabinet sides.
Step 4
Paint the trim board, paying particular attention to the nail heads, so that it matches the color of the original cabinetry.