Since it needs to be constructed, think ahead! Make it right after your guide boards, before you start the cabinet.
Example given: BF cabs port/handle
1: Take a piece of plywood (I prefer 1/4") about 1 to 1-1/2" larger than the diameter of your router base, you'll want the extra material later for clamping. On it draw center lines.
2: Center your holesaw where the lines intersect and cut the proper size hole.
3: Bisect the piece exactly in half. Use a thin kerf blade if you have one.
4: Take a piece of plywood long enough for both sides and rip it the appropriate width (On the first workpiece, measure from the edge of the hole to the edge of the plywood for the width), from it cut the template sides to length.
5: Apply wood glue to the mating edges and clamp in place until it takes a set. Allign it perfectly! This will be your finished opening so take time with it. If the sides are a little wide or a little narrow, make the template opening perfect and forget about the outside edge.
6: Cut a template top out of 1/4" ply the same size as your template.
7: Laminate the top to the previous assembly using wood glue and clamps. You can use a brad gun in lieu of clamps if you wish.
Once the glue is completely set, flip the template over and use your router with a bearing guided bit to remove the center of the top piece. Done correctly you now have a 1/2" thick router template with perfect sides and ends!
