2. Detailed Instructions – Getting to Know the Dovetail Notch

Feb 08, 2021

 

Getting to Know the Dovetail Notch

If you’re working offline (in the forest), you can download the instructions here: Lesson 2 Getting to Know the Dovetail Notch

The Big Picture

It is important to realize how the dovetail notch is created and how it functions as a building system. Dovetail style log building at its root is a straightforward means of creating an effective and aesthetically pleasing structure. All the angles and faces that are cut to create the shape of the tails are straight lines. This made it an attractive joint for cutting with hand saws and chisels in earlier times and is still favoured as one of the premier choices for log joinery in our times of modern power tools.

The general concept is to create a profile on the top of one log, known as the receiver. A matching or mating profile called the connector, can be cut on the underside of the next wall log allowing the two to fit closely and firmly together.

Each completed dovetail notch is a two-part system that requires wood to be removed from the mating surfaces of both logs. The receiver is cut first on the upper surface of the lower log. The receiver slopes away to the exterior of the building. The lower face or connector is then marked out and cut on the underside of the mating log. The goal is to create an exact matching profile of the receiver on the connector face, running at the same angle as the receiver but in the perpendicular direction. This results in a tight-fitting, locking joint in the corner.

Each log will have a complete dovetail at its ends; both a receiver face and a connector face. The receiver face is prepared to “receive” the next perpendicular wall log. The connector face sits on the receiver below and “connects” the two perpendicular logs at the corners of the building, this pattern then repeats up the walls.

 

Every Dovetail notch is made up of two parts: the receiver and the connector.

 

The Half Dovetail Notch

The half dovetail notch is a simple yet effective and aesthetically pleasing notch that has been used in log construction for centuries. As opposed to a compound or full dovetail notch, the half dovetail notch has only a single angle running across the width of the tail on the upper side and along the length of the underside of the tail. The full dovetail notch has angled cuts in the both the length and width planes on both the upper and lower sides of its tail.

Although it offers fewer locking qualities, the half dovetail notch is favoured because there are no angles on the notch that slope back into the building. Notches with angles that slope toward the building could be a potential moisture trap leading to rot. In other words, the half dovetail is a self draining notch. As well, more wood is left in the notch of a half dovetail because of the fewer angled cuts lending to a more robust appearance.

 

The Half Dovetail notch has no faces that angle in towards the building.

 

In order to be drawn to the idea of building a dovetail log house, one most likely has an appreciation for and an attraction to the clean crisp lines of a well-built dovetailed wall. Upon first inspection of a finely crafted structure, it can be confusing to imagine how the logs can be so well fitted together.  It is important to have a good grasp of the system as a whole but also the individual pieces that make up the completed log shell. We recommended that the necessary time be given to familiarize yourself with the shape and function of the dovetail from all faces and surfaces.  Let’s take a closer look at the half dovetail notch.

 

The Half Dovetail

Parts and Mechanics of the Half Dovetail Notch

Shoulders: The vertical cuts that define the finish of the dovetail at the interior most end of the tail.

Upper Face (or Receiver): The top side of the tail. This is cut with a slope always running to the exterior face of the log (and the building).

Lower Face (or Connector): The bottom side of the tail. The connector face is always scribed from the receiver face below to create an exact matching profile. The Lower face is always cut with a slope running towards the end of the log.

Chinking Set-Back: The shoulders on the exterior face are cut 3/8” to the inside of the shoulder scribe line to create a gap that can accept a foam backer rod and chinking. This is done to provide a means of better sealing up the logs where the shoulders meet the perpendicular wall logs.

Notch Drop: Describes the amount that the receiver (and therefore the connector as well) slopes or drops across the width of the log.  Notch drop is approximately 15 degrees.

This translates to a drop of: (For simple numbers)

  • 1 ¾” across a 6” thick log
  • 2 ¼” across an 8” thick log
  • 2 ¾” across a 10” thick log
  • 3 ¼” across a 12” thick log

 

The slope of the half dovetail faces should always run to the exterior of the building.

 

If you’re working offline (in the forest), you can download the instructions here:

Lesson 2 Getting to Know the Dovetail Notch