When, however, one piece is butted against the other, the piece that has its grain parallel to the plane of the joint is drawn away from the other as it contracts, leaving an opening at 0 (Fig. 146).
To hide this opening by its shadow a bead is often " stuck" on to the piece, as shown at b, Fig. 147.
Or in angles exposed to injury, such as those of chimney breasts, passages, etc., a bead is formed so as to avoid the sharp arris (Fig. 148).
This forms what is called a staff bead.
Interior angles, such as those of dados or skirtings, may be formed with a simple joint as in Fig. 148. In this case the opening caused by shrinkage is not visible (except on the top edge, which is generally mitred as far down as the depth of the moulding), as it is covered by the wall.
The above joints, slightly modified, are all applicable to acute and obtuse, as well as to right angles.
When the angles on both sides are seen, one piece may be housed into the other, as in Fig. 151.