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December 11, 2017

Dovetail Joints and When To Use Them

Dovetail joint componentsA Dovetail Joint consists of a series of tightly fitting, interlocking pins and tails used to join two boards together with the most common everyday example being in drawer construction.

Traditionally cut by hand, hand-cut dovetails require a high degree of precision to ensure a tight fit, and so require great skill as well as a good deal of practice. The pins and tails must fit together perfectly and there’s no room for error – too tight and the joint will not fit together; too loose and the joint will wobble or fall apart. As a result hand cut dovetails are regarded as a mark of the woodworker’s skill, and if you want to see how an expert cuts them by hand, have a look at this video Hand Cut Dovetail Joints

Dovetail Joint Benefits

So, if they’re so hard to produce, why go to the effort of using them? The main reasons are;

  • they are a very solid, long-lasting joint; in particular, their resistance to being pulled apart. They combine the mechanical properties of the interlocking pins and tails with a large gluing surface, so that even if the glue fails the joint will still hold together
  • they are extremely attractive, allowing a feature to be made of the joint itself with the ability to produce unique, custom joints
  • because they are so difficult to produce, they demonstrate the woodworker’s skill and are viewed as a mark of an expert

Historically, dovetails were used for mainly practical reasons, in particular the strength of the joint, although even the craftsmen of previous generations liked to show off their skills. Today they are used more for decorative and aesthetic reasons and have come to symbolize fine craftsmanship on the part of the maker, and quality of the product itself.

Due to the difficulty and time-consuming nature of cutting dovetails by hand, a lot of woodworkers use a Router and a Dovetail Jig and never learn to cut dovetails by hand. With high end dovetail jigs like the Leigh D4R it’s possible to produce unique, customized dovetails that are every bit as attractive as hand cut dovetails. There are 3 main types of dovetail joint:

Through Dovetail Joints

Through dovetail jointWith a through dovetail (also known as plain dovetail) joint, the tail sockets are cut all the way through the pin board and so the end grain of both boards is visible when the joint is assembled. Through dovetails are used in carcass and box construction where strength is important and it does not matter that the ends of the tails are visible, and are also used to attach the sides of a drawer to the back. They are sometimes used on the front of a drawer but only when the design of the piece requires it.

A through dovetail joint is particularly attractive when two different, contrasting woods are used. In addition, by varying the size and spacing of the pins and tails, the woodworker is able to create a completely customized joint. This is possible when cutting dovetails by hand or when using a high end dovetail jig like the Leigh D4R.

Use through dovetail joints for:

  • Carcass and box construction
  • Attaching the sides of a drawer to the back

Half-Blind Dovetail Joints

Half blind dovetail jointA half-blind dovetail is used when the end grain is not to be visible from the front of the item. The half-blind dovetail is exactly as the name suggests – half of the dovetail joint is visible, while the other half of the joint is hidden.

With a half-blind dovetail the tails sit in tail sockets that do not go all the way through the pin board (and as a result a half-blind dovetail joint is not quite as strong as a through dovetail) and so the ends of the tails can’t be seen from the front. The pins and tails can be seen from the side however, which still allows scope for producing an attractive joint. Quite often people will pull open a drawer and check to see if dovetail joints have been used in order to get a feel for the quality of the piece.

In quality furniture, half-blind dovetails are used to fasten drawer fronts to drawer sides because when you pull the drawer front to open the drawer, you are pulling the tails and pins tighter into the joint which makes it an extremely strong joint.

On a drawer front a half-blind dovetail can either be flush with the drawer front, as illustrated, or can be rabbeted so that the front of the drawer extends beyond the sides of the drawer.

Use half-blind dovetail joints for:

  • Attaching drawer fronts
  • Any time you do not want the joint to be visible from the front

Sliding Dovetail Joints

Sliding dovetail jointA sliding dovetail joint is used for connecting two pieces of stock at a right-angle and consist of a single tail cut along the edge of one board which slides into a corresponding pin slot in the other board. This joint has the interlocking strength of a dovetail so that the tail board cannot be pulled straight out of the pin slot, which makes tasks like joining shelves to cabinet sides much easier.

The joint can be further improved by tapering the pin slot towards the back of the joint which makes it grip the tail tighter the further it is pushed in. This makes it easier to assemble the joint and also stops the tail board sliding out of the pin slot, and in some situations, the taper can also be used to keep the joint tight with gravity.

The sliding dovetail is an ideal joint for joining shelves to a carcass, legs to a pedestal table, and a variety of other furniture components that require strong, mechanically locking joints.

Use sliding dovetail joints for:

  • Joining shelves to cabinet sides
  • Joining legs to a pedestal table
  • Any time the intersection occurs along the length of one of the boards, not at the end

Which Dovetail Jig Do I Need?

An important consideration to bear in mind when you choose a dovetail jig is that not all the dovetail jigs on the market are able to cut all of the dovetail joints.

To see at a glance which jigs can cut which joints see How to choose the best dovetail jig for your project