Cutting Out The Dovetails — Joint Variation: Double Dovetail

Secure your piece low in the vise and saw down the four sides of the tails, remembering that the critical aspect is the squareness from front to back. If it helps, create your initial saw kerf straight down, and only once it’s well defined, tilt your saw plate to follow the angled layout lines.

Saw down the sides of your tails with a fine toothed back saw

Remember to cut on the waste side of each line

You must now mark the definitive shoulder lines using a knife and square. To do so, register your square as before and bring the corresponding piece to find the exact distance from the end. Keeping the square fixed in place, take the pin piece away and run a knifewall to clearly delineate the tails from the waste; that is, on either side and in between the two tails.

Bring your pin piece back in to help position the square

Create a knifewall on either side of and in between the tails to define the exact cut line

Make sure to skip the actual tails as this leaves ugly looking marks

Next, transfer the shoulder line to the two edges and to the inside face by finding the knifewall with the edge of the knife and sliding your square against it to ensure a continuous knifewall all around. (Remember to ‘skip’ the tails with the knife on the inside, even though that edge will never be seen.)

Transfer the knifewall to the other side using the knife in the corner to register your square

This will ensure all shoulders will be square and inline

Your first and last knifewalls should be aligned perfectly. Check again and correct if they do not.

Clamp your workpiece in the vise and create a step-down on the waste side of the knifewall before sawing along the shoulder line. Clean up the shoulder with a sharp chisel, making sure you don’t undercut. Flip over and repeat on the opposite edge.

Create a relief before sawing off the waste pieces

Ensure you avoid cutting into the shoulders

Trim any protruding fibres with a sharp chisel

To remove the pin recess from in between the two tails, lay your board on the bench and use a narrow (⅜” or 10mm) chisel to chop down the knifewall. Start with light chops to avoid moving the knifewall over by excess compression.

Go back into the vise with your workpiece and pare down towards the bottom of the cut using the same or a narrower chisel. (A chisel that is too wide will eat into the sides of the tails.)

Take care to position the chisel accurately before you begin to chop the centre pin recess

Go back onto the benchtop to further the cut

Be sensitive to how hard you chop, as you don't want to compress the good wood and move the knifewall over

Note: Leave a flat right next to the very end when you are paring down to the knifewall. This rim will support the waste when you come to chop from the other side and will stop the whole piece from fracturing and leaving a big hole on the shoulder.

Once you have reached the halfway depth, turn over and repeat from the other side.

When you reach approximately half way, turn around and work from the inside face

Take light chops to start with as the wall is very shallow

The vise ensures your work won't slip accidentally

Choke up on your chisel when you are about to break through

To clean up the pin recess, clamp the board in the vise and pare cut squarely to the face with a sharp, narrow chisel. Choke up on the chisel so that you do not overshoot and accidentally break off the unsupported fibres on the other face.