Make a dovetail guide
A guide to help you easily cut perfectly angled dovetail pins and tails more quickly and accurately with less effort.
Perhaps you’ve thought about cutting dovetails but felt they would be too difficult. Maybe you tried but the results were disappointing. Or perhaps it’s been so long since you last cut dovetails that your confidence level has waned.
Well, this little dovetail guide won’t replace practice and attention to detail, but it will help you with one critical part of cutting dovetails: precise, accurate sawing. With this guide you’ll be able to make straight, square cuts at perfect angles. You’ll still need to cut out the waste using a fret or jewellers’ saw, and then chisel down to the scribe line.
The guide is quick and easy to make. While not necessary, adding a laminate face will extend the life of the guide. You can also glue a couple of pieces of sandpaper on the bottom of it to help keep it in position while sawing.
The angle you choose to use for your guide is a matter of personal preference. Any angle between 7° and 14° will work. Before making your guide, you might want to draw out different angles on a piece of paper and select the one that’s visually most pleasing to you. You could also make a few guides covering all the angles you will want to cut. If you do plan on making more than one guide, gluing one wider blank up, then cutting each guide from it, is an easier approach.
The centre block and two wings make up the foundation of the guide. The dimensions don’t need to be exact, so size the guide as you’d like.
Clamp the two wings together first. Clamping them so their inner faces meet at 90° is important. You could even use a clamping block to ensure the two wings meet at a right angle.
Glue and clamp the body to the wing assembly. The body will provide a lot of strength to the guide.
A Careful Cut
Mark the desired dovetail angle on both sides of one wing then cut both sides of the guide. This operation is easier if you’re working with a wider blank. Be sure to use a clamp and ensure it’s not going to come into contact with the blade during the cut.
Drill Magnet Holes
Angle your drill press table to double the angle that you set your mitre gauge to when trimming the guide to width. For example, if you cut the edges of the guide to 8° set your drill press table to 16°.
Shown here is a good collection of tools to have if you’re going to be hand cutting dovetails.
Prepare the blanks
You need only three small pieces of wood for this guide. Any hardwood will do, and the exact dimensions aren’t critical. For my guide the centre block is 7/8″ by 1-1/8″ by 1-5/8″. One wing is 1-5/8″ by 2″, the other (cut at the dovetail angle) is 1/2″ longer. The wings are about 1/4″ thick. The width of your saw blade and the thickness of the centre block will determine the maximum cutting depth. I’m able to cut pins and tails to just under 1″ long.
Glue them together
While you could glue the whole piece together at once, I find it easier to glue the two wings together first, and then glue the centre block to the wings. The glue needs to set only for an hour or so before you move on to the next step.
Cut the dovetail angle
This is the critical part of the project. Begin by marking the dovetail angle of your choice on the longer wing, then it’s off to the table saw. The block is small so exercise caution. I found it best to clamp the block to a sacrificial fence attached to the mitre gauge. You’ll need to reset the mitre gauge to cut the opposite side of the block. You want to maintain the exact same angle on both sides of the block.
Drill magnet holes
Set your drill press table to the angle you used at the table saw and drill holes for the magnets. I use the 3/4″ cupped magnet set from Lee Valley (#99K3905) because the magnet can be easily removed from the cups and reused. The 3/4″ magnets in the #99K3325 set are difficult, if not impossible, to remove from the metal cups. Use a Forstner bit and take your time drilling the holes. You want the magnet flush or a hair’s breadth below the surface. (Note: If you decided to apply laminate to the surface of the guide do so before drilling the holes.)
You don’t need to clamp the guide in place. Use your thumb to apply forward pressure on the clamp, your index finger to apply downward pressure and the other three fingers to apply pressure to your workpiece. Pencil in all the cut lines and then saw all the lines at the same angle. Then turn the workpiece around and saw the remaining lines. Make sure to stop your cuts just shy of the baseline. The guide will take care of the angles for you.
This guide won’t turn you into a dovetail guru overnight; for that you’ll still need a fair amount of practice. But it will speed things along, enabling you to cut perfectly angled dovetail pins and tails quickly and accurately.
What you need to get started
Along with this dovetail guide you’ll need a thin blade saw (my Japanese saw has a .30 mm blade with .05 mm of set on each side); a fret saw (their narrower blades work much better than the thick blades on coping saws); a few chisels (make sure they’re sharp!); a mallet (for thumping those chisels); a marking gauge (to lay out the dovetail baselines); and a thin blade knife (to transfer layout lines to the pin board). For information on how to cut dovetails read “Hand Cut Dovetails” (Feb/Mar 2009).