The Simplest Doweling Jig for Accurate Joinery

There are as many ways to join wood as there are types of wood. For most beginner woodworkers, and a many seasoned pros, dowel pins are a quick and easy way to do joinery. It is also inexpensive and needs very little in the way of tools. Aligning the holes to get the two pieces square can be tricky. Alignment pins can be used to mark the locations of the holes, but they do not always line up. Doweling jigs are expensive and tricky to use and dont always give great results. Whenever I want to use dowel pins, I make up a quick jig using scrap wood. This jig helps to create strong, tight fitting and above all, square joints.

Supplies

Drill
8mm Wood bit. Mine has a depth stop attachment.
Small drill bit (3mm or less) for drilling a pilot hole
Counter-sink bit
Any piece of scrap man-made board such as MDF, Chip Board or Plywood. I have even used clear polycarbonate in the past. It helps if you can cut this to the same width as the pieces you want to join, but it is not necessary. It must have at least two square edges.
Small piece of hardwood scrap about 30mm wide. It must have at least 2 square edges.
Two woodscrews
Square
Sharp pencil
Small Clamp
Wood pieces you need to join. The faces to be joined must be square
8 mm dowel pins
Wood glue

Step 1: Align the Jig to the End Grain

Align the end grain, the alignment block and the clamp block so that they are square. The end grain should be aligned to the top of the alignment block, and the clamp block squared to the end grain. Clamp the alignment block and the clamp block together so that they form a T.

Step 2: Drill 2 Pilot Holes and Counter Sink the Screws

Using the small drill bit, drill 2 small pilot holes through the alignment block and the clamp block. Create a counter sink in the alignment block using the counter sink bit. Screw the two pieces together making sure that the heads of the screws are below the level of the alignment block

Step 3: Mark the Location of the Dowel Hole and Drill

Use the pencil and the sqaure to mark the location of where you want the dowel to go. This is normally situated in the middle of the jig. If a larger joint is being created you may want to add additional dowel pins or offset the dowel pins. In this case I placed the dowel pin in the centre of the jig. Drill the hole using the 8mm wood bit. (A small piece of scrap wood under the alignment block helps to create a clean hole.) And that is it. your jig is done and ready to use!

Step 4: Using the Jig to Drill the Face Grain Side

Mark the face grain side of your jig "A" and the end grain side of your jig "B". Align the two pieces of wood you wish to join next to each other and mark the face grain "A" and the end grain "B". I find it helps to draw a line across the two pieces so that I always know which two faces go together. Align the face grain side of the wood with the face grain side of the jig. The two pieces should align at the top. Clamp the two together and drill an 8 mm hole in the block. Be careful not to drill all the way through wood. If you don’t have a depth stop, a piece of tape on the bit helps to determine how far to drill.

Step 5: Using the Jig to Drill the End Grain Side

Align the end grain side with the "B" side of the jig. The clamping block should sit at a right angle to the end grain piece making it easy to clamp. Drill an 8mm hole for the dowel.

Step 6: Fit the Dowel and Check for Square

Place a dowel pin into the face grain side. Align with the end grain side and close the gap. Check for fit and squareness using the square. You should have a tight fitting, right angle joint. Once all your joints are complete you can disassemble, glue and clamp your pieces together.

Step 7: Using the Jig for Rails

The same jig can be used to create rails on a chair or table. Using a pencil, mark the location where the rail is to be fitted to the post. Mark the two pieces A and B with A being the face grain and B being the end grain. Align the top of the jig to the pencil line on the face grain and drill the dowel hole. Follow step 5 to drill the end grain.

Step 8: Place the Dowel

Place the dowel pin into the holes and press the two pieces together. Check for squareness. Once all the joints are drilled, you can glue and clamp the pieces together.