If you have big holes — from using recycled wood or from a loose knot, for instance — you can fill them with another piece of wood, called a dutchman. This technique has been around as long as people have been working with wood.
Some purists cringe at the thought of using wood that has a blemish large enough to require a dutchman, but in the American Southwest, where using recycled wood raises the value of furniture, dutchmans are common. The procedure is pretty simple, and it’s made even simpler with a plunge router, a 1⁄8-inch straight-cutting bit, and two collars: one 5⁄16-inch and the other 9⁄16-inch. You can buy kits that contain these parts at most woodworking tool suppliers. They’re called inlay kits or inlay bushing bit with removable collar. The process with this setup is as follows:
Measure the size of the defect in your project and add a little extra around it. Cut out a hole in 1⁄4-inch plywood or Masonit, adding about 1/2 inch or so on all sides.
Be sure to use a large enough piece so that you can clamp this piece to the wood you want to work with and have enough room for the plunge router to move freely in the template.
Attach the 5/16-inch collar to the base of your plunge router, followed by the 9/16-inch collar.
Insert the bit into the plunge router and set the depth of cut to 1/8 inch.
Clamp the template onto the board with the defect, making sure that the hole in the template is over the defect.
Run your plunge router clockwise along the inside edge of the template.
Carefully route or chisel out the remaining material in the center of the template.
Remove the outer collar (the 9/16-inch one) and lower the depth of cut to 3/16 inch.
Select a piece of wood that has a similar color and grain pattern to the wood where the defect was and clamp the template onto it.
Route clockwise around the edge of the template.
Be sure to keep tight to the edge of the template; otherwise, you’ll cut into the dutchman itself.
Remove the dutchman from the scrap wood by setting your table saw to cut 1/8 inch into the board.
If you use 3⁄4-inch stock, set the rip fence 19⁄32 inch from the side of the blade farthest from the rip fence. (If your blade has a kerf of 1⁄8 inch, the rip fence is 15⁄32 inch from the side of the blade closest to the rip fence.)
Set the depth of cut in the table saw so that it’s higher than the dutchman on the board.
With the dutchman facing out, run the board through the saw.
The dutchman will fall out of the board as you run it through.
Apply glue to the underside of the dutchman and a little to the receiving groove and then press it into place.
You may need to tap it lightly with a mallet. Use a scrap piece of wood of the same species to tap against. Doing so will keep you from damaging the wood. The dutchman will stick up 1⁄32 inch from the surface of the wood.
Sand the dutchman flush after the glue dries.