Flat-Frame Jointing Techniques

This is the most basic wood joint which is only held together by putting glue between the two pieces of wood then allowing them to set while being held together using cramps. It is a very weak joint unless strengthened with pins or screws. The butt joint can be used either as a corner or a T-joint. It is mainly used for rough work and construction, for example, basic crates and the eaves of buildings.

This is also a weak joint unless it is strengthened by nailing into saw cuts across the joint. Mitre joints are neater than butt joints because the end grain is hidden. Mitre joints are typically used for the corners of picture frames and mirror frames.

Dowel joints tend to be used for lightweight frames. They have replaced many traditional joints in factory-made furniture. For example, when joining rails to legs for a table or chair, it is easier to use dowel joints rather than mortise and tenons. It requires two holes to be drilled into each piece of wood, the dowels are inserted into the drilled holes then the surfaces to be glued are cramped together. The dowels themselves are often made from a hardwood called ramin and come in a range of diameters. Just like a butt joint, dowel joints can be used as either a corner or a T-joint.

CORNER HALVING JOINT

A corner-halving joint is a quick and easy joint to cut. It is used for lightweight frames and is often found in door frames, mirror frames and picture frames. Wood of equal thickness is used for both parts of the joint.

HAUNCHED MORTISE & TENON JOINT

Haunched mortise and tenons are often used when joining corners of frames or rails to the end of legs. The tenon is offset to prevent it breaking through the end grain of the leg or stile. The haunch, which forms a small intergral part of the tongue on the tenon, supports the top edge of the rail. It is one of the strongest joints because of its large gluing surface area and crossing of grain. The tenon fits into the mortise and is glued and cramped together.

T-HALVING JOINT

The t-halving joint is similar to the corner-halving joint but in this case one of the pieces joins the other in the middle to form a T. They are often found in frame constructions, and due to the surface area where the grain cross, the glued -up joint is reasonably strong. Wood of equal thickness is used for both parts of the joint.

DOVETAIL JOINT

Another T-joint, the dovetail halving is one of the most complex joints to make accurately, and as a result it is ususally found in expensive furniture. Due to its large surface area and the grains crossing it is a strong joint. It has added strength because the dovetail is locked in along its length.

STUB MORTISE & TENON JOINT

The stub mortise and tenon, also knows as the stopped mortise and tenon, is one of the strongest frame joints and is therefore one of the most frequently used joints on chairs, stools and tables. The main advantage is that once glued up, there are no obvious signs of the joint on the outside of the leg. The depth of the mortise should be about 3/4 of the width of the leg or stile.

THROUGH MORTISE & TENON JOINT

The through mortise and tenon is very similar to the stub mortise and tenon, except this time the tenon goes all the way through the width of the leg or stile as shown. This type of T-joint is, again, very strong. This joint is often used to join the middle rail to the stiles when making a door frame.

CROSS HALVING JOINT

Cross-halving joints are often found in frame constructions where you have a rail and a centre stile crossing over each other. Wood of equal thickness is used for both parts of the joint and half the timber of the joint is removed from each piece of wood. It is quite a strong joint and can be used on door and window frames due to the joint being flat on both sides.

BRIDLE JOINT

Corner bridle joints can be used on frame constructions which will not be subjected to high sideways pressure as this can force the joint out of square. It is a stong joint due to its large gluing area and the fact it can be twisted apart. Similar to the butt and dowel joints, the corner bridle can be adapted to make it a T-joint when required.