Measure the dimensions of the corner cabinet frame and write the width and height figures down. Measure the length of both corner cabinet openings, since the L-shaped cabinet opening may differ in length. Include the frame panels in the length measurements. In addition, measure the total height of the corner cabinet, including the frame panels, so the L-shaped corner door will cover the panels after installation.
Lay the plywood sheet down so you can draw the two panels required for an L-shaped desk door. Grab the pencil and a ruler to draw two panels. The panels must measure the total height and respective width of the corner unit. Subtract 1/2 inch from the width dimension off one of the door panels, so the 1/2-inch-thick overlapping panel does not alter the custom L-shaped cabinet door.
Cut the two cabinet door panels using a table saw. Remove splinters and cracks by sanding the cut edges and surfaces with sandpaper.
Create an L-shaped cabinet door for your desk by placing the two panels perpendicular beside one another. Ensure the altered piece is overlapped by the other piece, meaning the 1/2-inch thick cabinet door adds 1/2 inch to the adjusted door panel. Drill 1-inch-long screws through one door panel using the cordless drill. The screws should extend into the second door panel creating an L-shaped door structure.
Install two hinges on the outside cabinet side panel on the right-hand side of the L-shaped desk cabinet where you wish to add the new door. The hinges must be on the outer side. Use the screwdriver and the 1/2-inch hinge installation screws to install the hinges. Space the hinges evenly apart on the cabinet unit so the door has balanced support from the hinges.
Hold the L-shaped cabinet door up to the L-shaped cabinet opening. The hinges should fall on the inside of the cabinet door. Open the door slightly to see the hinges on the inside panel. Install the hinges to the inside cabinet door using the screwdriver and several 1/2-inch hinge screws. Use at least three or four screws per hinge on both the door and the cabinet side panel.
Install the cabinet door hardware onto the L-shaped cabinet door on the door opposite of the hinge installation. Place the knob or the handle on the outside door panel. Install your hardware by inserting screws into the cabinet door from the inside out.