This router planer jig allows the home woodworker to plane lumber without the need for an expensive benchtop planer.
How often have you avoided projects that require "thin wood" because you don't have a planer to make it? Almost every plan for a jewelry box or cigar humidor needs 1/4" - 3/8" lumber. Until now, your options were limited. You could plane the lumber yourself or pay extra to have it done for you.
This jig will allow you to reduce the thickness of your boards almost as easily as you could with an expensive shop planer. The principal behind the jig is relatively simple; the router is fitted with a straight flute bit and is held at a fixed distance above the workpiece by runners. As the router is moved over the board, it cuts away the surface and reduces the thickness of the board.
Cut the Rods Many routers have holes or slots in the side of the base that allow for the use of an edge guide or fence. In this plan, we used these holes to mount our router to the jig. The jig's rods should be slightly smaller than the holes in the router's base. The rods for our jig are approximately 16" long and are made from stainless steel for rust resistance.
Note: If you do not have a router with this feature you will need to substitute a sheet of Plexiglas or plywood in place of the rods.
Rip the Runners
The runners should be made from a hardwood and cut to approximately 3"x12". After you make the two runners you will need to rip them again into two pieces; 1" and 2"
Each runner should now be made from two pieces; 1"x12" and 2"x12"
Drill The Runners
Clamp the runners together and drill a hole, slightly smaller than the diameter of the rods, through the center of the rip line. The exact position of the holes you drill will depend on your router.
Drill for the Bolts
Next we will drill a hole for the carriage bolt that will hold the two halves of each runner together. You will need to drill a hole completely through the center of the rail's width.
Next use a Forstner bit to drill a hole on both sides to conceal the carriage bolt's head. The holes you drill should be slightly larger than the carriage bolt.
Sand and Finish
Lightly sand the runners and finish with a light coat of polyurethane.
Using the Planer
To use the planer assemble the jig and put a straight flute bit into your router. Lock your router onto the rods and position the jig over the workpiece you wish to plane.
The work surface should be flat, smooth, and free from defects. Any bumps or imperfections will be transferred to your work.
Setting the DepthStart
by setting the depth of cut to a small pass (1/8"). Don't try to remove too much material in one pass. Important: Make sure the workpiece is clamped securely so the router will not kick it back. Also make sure the clamps don't interfere with the movements of the jig.
Remove the stock from the wood in multiple passes of 1/8". Your final pass should be 1/16"
Sand and Finish
Sand the workpiece and finish.
The picture to the right shows a sample of cherry that was planed using this technique. It was slimmed from 3/4" to 1/8" in about 10 minutes.