Make the Hole in the Bench

• 1). Determine the size of the hole that you want. The router will be mounted on the bottom of the benchtop, with the router bit sticking up through the surface. The hole in the benchtop should be slightly larger than the largest router bit you intend to use. The diameter of the large circular hole in the jig that you will make in the next step needs to be the diameter of your router base plus the diameter of hole you want--the diameter of your bit. If you have a 6-inch router base with a ½-inch bit in it, and you want a hole that is 1 ½ inches in diameter, the diameter of the jig hole needs to be 7 inches: 6 + 1 ½ - ½ = 7.
  
  
• 2). Make a jig that consists of a large piece of hardboard or plywood with a circular hole in the middle of it. Draw the hole with a compass or round template and cut it out with a jigsaw as accurately as possible.
  
  
• 3). Securely fasten the jig to the top of the bench that you will be cutting the hole in, with the location of the planned hole at the center of the hole in the jig. The jig can be secured to the bench top with clamps, or by screwing it directly to the top, if you don't mind having a few small screw holes in the benchtop when you're done.
  
  
• 4). Drill a hole through the benchtop at the center of the jig to make routing safer and easier, using a drill bit that is a larger diameter than the diameter of your router bit.
  
  
• 5). Insert a sharp straight bit into your router. Put the bit into the hole that you just drilled. Be sure that the bit extends through the bottom of the bench top. Turn on the router and slowly and carefully enlarge the hole, until you are running the router base around the inside edge of the jig, thus creating a round hole.
  
  

Mount the Router

• 1). Turn the bench over and position the router so that its base is sitting against the bottom of the benchtop, centered on the hole you just made.
  
  
• 2). Securely screw the router to the bottom of the bench.
  
  
• 3). Turn the bench back over and set it firmly on the floor. Test run the router with no bit in it to be certain it is secure before using it.