The most used traditional joint for furniture

The log and mortise, mortise and tenon as you will find it in English documentation, is perhaps the most common wood joint, used in the manufacture of furniture as well as doors, windows or in construction. It is one of a series of traditional classical joints, along with swallowtail joining, lamb and uluc or the one with dowels. In fact, often these joints have been (and still are) combined for greater strength and aesthetic effect.

It is considered one of the oldest wooden joints

The oldest such joint discovered is thought to be over 7000 years old. It was found at a wooden fountain near Leipzig, itself considered the oldest intact functional construction. Joints with a log and hollow have also been found in Egyptian pyramids, in ancient furniture in Greece, Rome and Persia, and in buildings in ancient China. It's how the folk craftsmen of ancient times jointed wood so that it would last for centuries, even millennia.

The joint with a socket and a socket is simple and very strong and is used especially for joining elements at 90º. It is a log made at the end of a piece of wood that fits perfectly with a notch in another piece of wood. There are several variations of the joint, each of which adds strength or aesthetics or solves some more complicated problems.

Ways of making the joint with the stock and the socket

Joining is used when it is necessary for the object to withstand high forces. It is frequently used to join table or chair frames to legs, to fix poles to cupboards or bookcases, to simple staircases, to join door and window frames, to join beams in traditional construction.

In the past, the joinery was done by hand, with ordinary carpentry tools, i.e. chisels and hammer and saw. It was made in such a way that it required no other fasteners - glue, nails - the only 'fuses' sometimes used were pins or dowels. The stock and the notch were very accurately made so that they fitted together perfectly, the two elements functioning as a whole when joined.

Even now, such traditional joinery is still done, especially by those carpenters who are passionate about working with solid wood and who try to carry on the tradition. This is the case of Dragos and Costi, which I have written about on various occasions and who made, for example, the merger at the end of the article.

Unlike joints made in the past, adhesive is now used for safety. No screws, nails or other metal elements are used. The use of feathers from other wood species, in colour contrast to the basic wood (oak with mahon, frasin with nuc) creates a very pleasing effect by increasing the value of the furniture.

In addition to the old tools, they now use the circular cutter to make the stump and the router with special cutters and template to make the exact notch. It takes a lot of precision to make a strong joint. Even a small mistake leads to a lower strength of the joint and can spoil the symmetry of the design.

Rules to keep in mind when making items for a stock and socket joint

The size of the stump and the hollow depends on the thickness of the wood. The rules of good practice say that the stock should be one third of the thickness of the wooden element and the notch one third of its width (the width being considered the part that is the continuation of the element containing the stock, joined at 90º) and one sixth of its thickness. It is important that the joint between the log and the groove is very strong. Therefore, when the table, seat or pulleys have to withstand high forces, strength calculations must be made to determine the thickness of the stock and the length of the socket.

Another basic rule of thumb is that the hollow is made first and then the stump. The cap is made slightly larger than the notch after which it is adjusted. It is much easier to fit a large stock than to fit a joint whose stock is small and has play in the socket.

Notch is made in such a way that the heel fits snugly and not higher so as not to loosen the bond. The exception is the joint with a log and open (broken) notch. In this case the notch is actually a groove or hole in the wooden element.

The log should not be made very thin because it reduces the strength of the joint. It should have straight and smooth sides to easily penetrate the socket and fit perfectly.

Assembly between the two elements should be done a little bit forced, without playing, but without forcing too much. A joint where the log enters very hard risks giving way at the slightest expansion of the wood. For a secure fit, use adhesive. The glue is applied to the log and is set to be in excess thus ensuring that it reaches the entire contact surface. The excess will come out when the fixing is final. It is recommended that it is left until fully cured so as not to damage the joint. Removal is done after curing with a sharp chisel.

Types of socket and socket and stock joints

There are many known variations of the combination. The most popular of these are:

• the closed or blind joint, as the old carpenters call it. The notch does not penetrate the wood, the stump is not visible on the outside;
• open (broken) joint. The splitting pierces the wood and the stump is visible from the outside;
• double joint. On the same element, two plugs are made which enter into 2 notches on the other element;
• angle joint. The stump or notch is not in a straight line. They can be both at an angle or only one of them;
• combined with lambswool and uluc. The increased strength of the joint results from the combination of the two types of joints;
• loose joint with wedge. The stock passes through to the other side and has a hole drilled in it. After the joint has been made, a wedge is knocked into the hole in the stock to prevent it from splitting. This joint may not be as rigid as the others.

The joint can also be combined with the dovetail joint (the stock and the socket are made in the shape of a dovetail) or with the dowel joint, these being fitted on the sides of the element with the socket fixing the stock inside.

I've already told you about the joint where wedges are used for stiffening. As well as stiffening, it also increases the aesthetic effect. In the pictures below is such a joint handmade by Dragoș Costache from Iplan, one of the modern carpenters I mentioned above.

I hope that this time too I have come up with news, at least for some of you. If you find the information useful to others, feel free to share. If you have additions, queries or would like further information, please leave your comments below.