Remove the door from the cabinet with a screwdriver.
Remove any metal hardware, such as nails or staples, from the area around the center panel where you will cut the wood.
Using the router, cut the wood strip holding the center panel in the frame around all four sides so that it can be removed. Take care not to cut through the center panel and damage the frame on the front side.
Remove the center panel from the frame. If it is glued to the front lip of the frame, you may be able to loosen it using a blade. Take care not to damage the frame.
If it is a solid wood door, or the panel is glued and cannot be removed, use the jig saw or hole saw to cut out the center. Measure a width around the outside for the frame if needed. Approximately 2 inches is a good size for the frame, depending on the size of the door.
Use the router to cut a lip around the back side of the frame to set the glass against.
Smooth down the front side of the new frame using a sander or sand paper.
Use gloves when handling glass to protect your hands from sharp edges. If desired, you can ask the glass store to grind the edges of the glass so they are smooth instead of sharp.
Set the glass panel in place to make sure it fits. The glass panel should fit as close to the inside edges of the wood frame as possible, with about a 1/8-inch clearance.
Secure glass clips around the sides of the wood frame. Two on each of the four sides should be adequate. Do not tighten them down yet, turn them so that the glass panel can be slid freely into place.
Apply a bead of silicone sparingly around the lip of the wood frame and set the glass in place. This step is optional as the glass clips alone may be adequate to hold the glass. If rattling is a problem, the silicone can be used to cushion the glass.
Turn and tighten the glass clips to hold the glass panel in place.
Clean with a soft cloth and glass cleaner.
Reattach the door to the kitchen cabinet.