All About Dovetail Joints – The Complete Guide

We recently took a look at using dovetail jigs along with your wood router to create dovetail joints.

Machine dovetailing is commonplace today but many cabinetmakers still prefer dovetailing by hand.

Today, we’ll look at both machine dovetailing and the traditional hand-cut method but first thing’s first, what is this type of joint?

 

What Is a Dovetail Joint?

A dovetail joint is often simply referred to as a dovetail.

Dovetails are incredibly strong and durable because of the way the pins and the tails are shaped but what do these terms even mean?

These pins are cut to extend from one end of the board and they mesh with a series of tails at the other end. 

As soon as a dovetail is glued, it needs no further mechanical fastening at all and should last a lifetime. An incredibly strong joint anyway, once glue is added to a dovetail, it’s almost impossible to pull apart.

There are numerous types of dovetail joints but they fall into 5 broad categories:

1. Through Dovetails: These show on both sides
2. Half-Blind Dovetails: This type of dovetail shows on one side only
3. Secret Mitered Dovetails: As might be obvious, this kind of joint is totally hidden from view
4. Sliding Dovetails:  These joints are used to join 2 boards at right angles

 

What Are Dovetail Used For?

Used in many types of woodworking, dovetails are most commonly seen in these areas:

• Carpentry
• Cabinet making
• Furniture making
• Timber framing
• Log buildings

Dovetail Joints: Pros

• The strongest of all types of joint
• Present a large gluing area and, once glued, become almost indestructible
• Holds even without the use of glue
• Highly resistant to being pulled apart
• An attractive aesthetic indicating the sign of a true craftsman

Dovetail Joints: Cons

• Dovetail joints are difficult both to mark out and cut
• Poorly-made dovetails don’t exhibit any of the benefits listed above so it’s essential to get them right

And, with regard, to this final drawback, that gets a whole lot easier if you machine cut dovetails…

 

Machine Dovetails

Not only does machining dovetails ensure accuracy and uniformity, you’ll also be able to complete a hugely time-intensive element of joining rapidly and repeatably.

Check out our dovetail jig reviews for 5 of the best options at your disposal to help you get this done. You’ll also need a router.

Arguably the key benefit of a machined dovetail is the fact they’re more structurally sound than hand-cut joints since it’s almost impossible to get the fit wrong.

On the flipside, the tails and pins are equally spaced which gives you much less flexibility than taking the job on by hand.

Using a wood router rather than a commercial, semi-automatic machine again limits you to some extent. Many of the better examples give you plenty of scope, though.

Properly setting up the template provided is crucial to the finished result. As with any woodworking equipment, follow the instructions closely as templates differ substantially from manufacturer to manufacturer.

Regardless of the type of template, you’ll screw it to a backing board. You can either clamp this to the workbench or hold it in a vise. 

Hand Cutting Through Dovetails

We’ll round out by walking you through cutting through dovetails by hand.

We’ll focus on this type of joint since it’s the strongest and also the easiest to cut by hand.

Setting Out

• Cut the sides off square to the final length. Allow 1/16-inch in total (1/32-inch at either end) to allow tolerance for cleaning up after assembly
• Gauge the thickness to a tolerance of +/- 1/32-inch. Make sure you use a cutting gauge since a marking gauge will scratch your workpiece
• If the 2 pieces are of equal thickness, you’ll only need to set the gauge once. If not, you’ll need to fine-tune the gauge for each piece
• Gauge around all 4 sides making sure there’s a thin and crisp cut. This will form part of your finished joint
• Mark and cut your tails and pins as required. Cutting the tails first allows you to work on the face of the board although there’s no fixed rule as to which you cut first
• Make sure you have a pin at each end. Make sure these end pins are not so fine that final sanding goes through them
• Mark this width on each side. Next, mark half this width parallel to either side using a pencil
• Divide the distance between your lines into equal spaces according to the size of your intended dovetails
• Transfer the marks by squaring the lines to the end
• Mark half the width of the narrow part of the pins next to each line. Using either a bevel or a template, draw in the rakes…
• The slope can vary from 1:5 inches when strength is crucial to 1:8 inches for fine work
• Once you’ve marked the tails, square the line across the end. Sharp and hard pencils work well for this purpose

With the setting out in place, it’s time to get cutting…

Cutting

• Use a sharp and fine saw and cut down the raked lines. Make sure the workpiece is held in a vise. Cut square across the top and down to the gauged lines. Try tilting the workpiece to ensure all cuts are vertical
• Use a sharp chisel with a bevel edge to chisel away the waste. Cut vertically then diagonally until roughly half the waste is removed. Turn over and repeat until it’s all cleared out. Clean up the corners at this stage, too

Next, it’s time to mark the pins.

Marking Pins

• Put your other workpiece in the vise and lay the cut workpiece over the top. Hold it with one hand and mark the tails with the other
• Square the lines to the gauge marks then mark the waste
• Saw along the waste side of these marks to cut the pins out
• Use the chisel to cut away the waste
• Clean up all your joints

With everything in place, you can assemble your joints.

Assembly

• Try each dovetail for fit but only part way. Give it a few gentle taps with a soft hammer
• Pop some resin glue in the gaps and allow it sufficient time to set
• When assembling, tap with your sift hammer then clamp into place
• Wipe off any excess glue and plane or sand the corners to finish

 

Final Word

Whether you choose to cut dovetail joints with a jig and router or by hand, mastering this element of woodworking is a sure sign of craftsmanship.

We’ve got plenty more in store for over the coming weeks here at Miter Saw Judge with a combination of more informational guides and some exciting new products we’ve just finished testing and will report back on early next week. Check out our buying guides right here and come back soon!