Butt joint

Additional reinforcement through ties and plates is often used to improve the characteristics of butt-jointed structures.

The joint is widely used in many applications due to its simplicity, notably in rough carpentry and construction.

For enclosed constructions, such as four-sided frames or boxes, the thickness of the two adjacent members must be taken into consideration.

The technique of skew-nailing is applied so that nails are not parallel to each other and so resist the pulling apart of the joint.

Holes are often drilled with the assistance of a dowelling jig which aids in accurate hole placement — accuracy is paramount in this technique to ensure members line up perfectly in the completed joint.

They take on an oval shape in section owing to the different rate at which wood moves with different orientations of the grain.

It is drilled from the outside face of the frame piece to be joined and therefore generally leaves an exposed dowel protruding after glue dries, and the excess dowel head is thus usually flush cut.

The butt joint can often be joined temporarily and sometimes more accurately with simply glue, allowing faster set up than the usual tedious alignment procedures mentioned above.

Dowel trimming and sanding of the surface, followed by normal finishing then proceed in the usual manner.

The biscuit is an oval shaped piece of specially dried and compressed wood, usually beech, which is installed in matching mortises in both members of the joint in a similar fashion to a loose or floating tenon.

Accuracy is not as important in the creation of these mortises as the biscuit joint is designed to allow a bit of flexibility during glue up.

When the mortises have been cut, the biscuit is inserted with some glue and the joint is brought together, aligned and clamped.

The biscuit absorbs some moisture from the glue and swells up in the mortise, creating a tightly fitting joint.

For this reason, long screws are required (usually 3 times the thickness of the member) to ensure good traction.

In solid timber work it is common to counterbore a hole in the frame or carcase member to conceal the head of the screw.

This also allows more of the body of the screw to penetrate the adjacent member for greater traction.

The cam is then rotated with a screwdriver, capturing the post head, and pulling and locking the pieces together.