Simpler country furniture often had larger dovetails, or even a single tail and pin. This country pine cupboard from the 1890’s has big country dovetails:

Dovetail meaning

After the holding stage, the metal is slowly cooled down to room temperature, typically through air cooling. The gradual cooling helps prevent structural distortions that might occur due to rapid changes in temperature. The final result is a tempered metal with balanced hardness and enhanced toughness.

The hardening process consists of three key steps: heating, cooling, and tempering. The initial step involves heating the metal to a specific temperature, known as the austenitizing temperature. This temperature varies based on the type of metal and its desired properties. The heating is typically performed in a controlled environment to ensure uniformity in temperature distribution throughout the metal.

Dovetail joints often hold two boards together in a box or drawer, almost like interlocking the fingertips of your hands. As the dovetail joint evolved through the last one hundred thirty years, it becomes a clue for the age and authenticity of antique furniture. The type of dovetailed joint, especially in drawers, reveals much about furniture construction and dating. With just a little study of these examples, it is easy to spot true hand made construction vs. machine made furniture.

Dovetails Pants

The use of hand tools and hand-cut dovetails is now the province of hobbyists and a few small shops creating authentic replicas of antique furniture. This over-view of the dovetailing techniques should easily help identification and dating of most furniture from the last 200 years.

Dovetail Jig

Other drawer joints include sliding keyhole or French dovetails that were have been used since the 1890’s. Here is an oak cylinder roll desk from about 1895 with keyhole dovetailed drawers.

The next technological development in joinery was again American. In the 1890’s, American furniture began to be mass produced, with interchangeable parts and speedy production for the growing and affluent middle class. The slow and laborious crafting and carving, one piece at a time, by a master woodworker was not suited to the new mass market. Steam power, transferred by pulleys and leather belts, operated saws, carving machines and routers that could copy an original pattern exactly.

The holding stage follows the heating, where the metal is kept at the tempering temperature for a predetermined duration. During this stage, the microstructure of the metal undergoes changes, and the excess hardness or brittleness is relieved. The time spent at the tempering temperature varies based on the metal’s thickness and desired properties.

Single dovetail joint

Hand cut dovetails were used to hold the sides of drawers together, but also to join the structural members of case furniture. Hand made screws and nails were relatively expensive and could rust and expand, sometimes cracking the wood they secured. Glues of the period sometimes weakened. Dovetails have great strength, holding pieces of wood in perfect alignment over long periods of time. This lavishly hand-carved cabinet from about 1890 shows structural dovetail joints on the back side.

Dovetail joint uses

The tempering process generally involves three stages: heating, holding, and cooling. The first step is to heat the hardened metal to a specific temperature, known as the tempering temperature. The exact temperature depends on the metal type and the desired mechanical properties.

Tempering is a heat treatment process conducted after hardening to achieve optimal metal properties by reducing the brittleness caused by the rapid cooling. It involves reheating the metal to a specific temperature and cooling it down gradually. Unlike hardening, tempering aims to balance hardness with improved toughness and ductility.

Hardening is a heat treatment process employed to increase the hardness and strength of metals. It involves heating the metal to a specific temperature range, followed by rapid cooling, usually through quenching in water or oil. This rapid cooling prevents the formation of large crystalline structures, which would lead to a softer and more ductile metal.

Hardening and tempering are two distinct heat treatment processes that significantly impact the properties of metals. While hardening focuses on increasing hardness and strength, tempering aims to maintain a balance between hardness and toughness. Hardening involves rapid cooling through quenching, while tempering requires reheating and gradual cooling. The choice between the two processes depends on the specific requirements of the metal and the intended application. Understanding the differences between hardening and tempering is crucial for engineers and metallurgists to select the most suitable treatment for achieving optimal performance in their metal components.

Dovetails clothing

Here is an example of an Eastlake chest of drawers with characteristic “spoon” carving and “pin and cove” dovetails from the 1880’s:

Genuine hand made dovetails like these were the standard of good furniture craftsmanship until about 1870, when American ingenuity developed the “pin and cove” or round style dovetail, often seen on late Victorian and Eastlake furniture. These were cut with a jig or pattern, and an apprentice could create a very well fitting and attractive joint. Popular here into the 1890’s, these joints never gained acceptance outside of the U.S. and Canada. European cabinetmakers continued their hand-cut dovetails well into the 1900’s.

Types of dovetail joints

This secretary desk from about 1780 was built by a good country carpenter, notice the dovetails on the side of the drawer, and holding the top and side planks together as well.

Tempering ensures that the metal retains some of its original properties while gaining additional desirable characteristics. It reduces the hardness slightly but increases the metal’s toughness, elasticity, and resistance to sudden impacts or shocks. Moreover, tempering enhances the metal’s machinability and reduces the risk of cracks and fractures.

For thousands of years, a dovetail joint was created by a skilled cabinetmaker using small, precision saws and wood chisels. Tiny angled saw cuts were followed by careful cutting by a sharpened chisel on both sides to avoid splintering. One board had tiny “tails,” and the other had the larger “pins,” carefully measured to match and fit together exactly. When the joint is expertly executed, it is a thing of beauty, and a secure joining of two boards that can last for centuries. A little glue cements the connection, and a good dovetail joint has great strength and durability.

These routers were ancestors of the electric precision tools of today, and could be used to rapidly cut a machined dovetail joint. Each cut is exactly like the others, each “tail” and “pin” are exactly matched. A close inspection shows no irregular saw cuts or variation from a skilled craftsman, but rather a precise and identical manufactured machined joint. These machine-cut dovetails are as strong and long lasting as the hand-made joints, and became the standard of better American furniture ever since the late 1890’s. Here is an early example of machine-cut dovetails on a 1920’s sideboard from a dining set:

Once the metal reaches the austenitizing temperature, it is rapidly cooled to room temperature to attain the desired hardness. This cooling process, known as quenching, can be achieved using different mediums, such as water, oil, or air. The choice of the quenching medium depends on the metal’s composition and the desired hardness level. Water provides a higher rate of cooling, resulting in a harder metal, while oil offers a slower cooling rate, leading to a lower hardness.

Dovetail joint

European cabinetmakers continued to produce hand-cut dovetails through the 1930’s. Electric power tools, like routers and various types of saws were put into widespread use after World War II in the 1940’s. There was resistance – in England, carpenters unions went on strike over the use of electric saws, fearing the end of their livelihoods. Nevertheless, by the 1950’s, power tools were used in almost all furniture construction across Great Britain.

The name “dovetail” comes from the appearance of the joint, resembling the triangle shape of a bird’s tail. The earliest examples are from furniture placed with mummies in Egypt thousands of years ago, and also in the burials of ancient Chinese emperors.

Metals play a crucial role in various industries and applications due to their exceptional properties, such as strength and durability. However, these properties can be enhanced further through two common heat treatment processes: hardening and tempering. Though both processes involve heating and cooling the metal, they serve distinct purposes and have unique effects on the material. In this article, we will explore the differences between hardening and tempering of metals, shedding light on their processes and outcomes.

The primary purpose of hardening is to create a material that is resistant to wear, abrasion, and indentation. The hardened metal demonstrates a higher level of toughness, tensile strength, and resistance to deformation. Consequently, it finds extensive use in applications that require a sturdy and enduring material, such as tools, drill bits, gears, and various machine components.