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Orient the wood figure so the parts move in unison. Whenever possible, join the boards so the wood swells and shrinks in the same direction. When the wood grain must cross at nght angles, align the tangential planes. (See Figures 1-12 and 1-13.)

Cut large boards into smaller parts. When you must glue or otherwise fasten two boards with opposing wood grain, make sure they are as narrow as possible without compromising the strength of the structure. (See Figures 1-14 and 1-15.)

1-12 On the corner butt joint shown at the left, both the wood grain and the annual rings are opposed to one another. The joint will soon fail. On the middle joint, the wood grain is aligned, but the annual rings are not — the tangential planes are perpendicular to one another. This joint will fail too, though not as quickly as the first. On the joint at the right, both the wood grain and the annual rings are aligned. This joint will last ___ a long time.

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I-13 The wood grain on all three of these mortise-and-tenon joints is properly aligned. But on the joint at the left, the tangential planes are directly opposed on the broadest possible surface — where the cheeks of the tenon meet the sides of the mortise. This greatly diminishes the useful life of the joint. On the joint in the middle, the planes are in some what better alignment. The tenon moves radially at right angles to the tangential movement of the mortise. But the joint at the right shows the best possible arrangement — the tenon moves radially at right angles to the radial movement of the mortise, and the tangential planes are aligned.

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As a rule of thumb, most craftsmen limit the width of lap joints and mortise-and-tenon joints (where the wood grains of the members must be glued perpendicular to one another) to 3 inches when the tangential planes can be aligned, and less if they can't be.

Use "floating" joints to let the wood move. When you must join a large board to a structure and cannot cut it into smaller pieces, do not glue it in place. Instead, let it float in a groove or dado, free to expand and contract. (Sf.e Figure 1-16.) You can also make floating joints with screws and bolts. Cut a slot for the shank of the screw or bolt, allowing the wood to expand and contract around it. (See Figure 1-17.)

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1-14 This antique spice cabinet was built in the late nineteenth century, when boards up to 24 inches wide were commonly available. However, the craftsman who built it chose to make the back from narrow boards, since he had to attach them at right angles to the shelves. This has prevented the back from buckling as it expanded and contracted for almost a century.

1-15 This apron will be joined to a table leg with a mortise-and-tenon joint. Like all such joints, this presents a dilemma — the mortise grain is perpendicular to the tenon grain, so the two parts move in different planes, stressing the joint. The wider the mortise and tenon, the more the parts move and the more critical this problem becomes. To alleviate some of the stress that a single wide joint might generate, the tenon on the end of this apron has been "split'1 into two narrower ones, each less than 3 inches wide. Instead of one wide tenon expanding and contracting in a single large mortise, there are two smaller tenons, each moving only half as much in its own mortise — and only generating half the stress. And because the gluing surface has not been greatly diminished, this split mortise-and-tenon joint is still very strong.

1-16 Traditional frame-and-

panel construction, such as these cabinet doors, employs floating joints. The panels expand and contract in grooves cut in the inside edges of the rails and stiles.

1-16 Traditional frame-and-

panel construction, such as these cabinet doors, employs floating joints. The panels expand and contract in grooves cut in the inside edges of the rails and stiles.

1-17 The shank of this roundhead screw rests in a slot, allowing the wide board to expand and contract around it. When making floating joints for screws and bolts, cut the slot with the long direction parallel to the direction of the wood movement. Drive the screw snug in the slot, but not so tight that it restricts movement.

1-17 The shank of this roundhead screw rests in a slot, allowing the wide board to expand and contract around it. When making floating joints for screws and bolts, cut the slot with the long direction parallel to the direction of the wood movement. Drive the screw snug in the slot, but not so tight that it restricts movement.

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Use small nails for floating joints when applying a small molding, as many old-time woodworkers did. The grain direction of a molding is often perpendicular to that of the board to which it's applied. If you secure the molding with brads, these tiny nails will bend slightly as the wooden parts expand and contract.

Avoid wood that may deform and stress the joint. As mentioned previously, wood not only moves, but also may change shape. Study the wood figure to anticipate how a board might deform. If this deformation will create stress in the joinery, use another board. (See Figike 1-18.)

If possible, control the deformation. Wood will expand and contract no matter what you do. If you restrict the movement, you will make matters worse. Wood will deform, too, and though this can't be stopped, it can often be controlled. For example, a well-placed batten, brace, or screw can control cupping. (See Figure 1-19.) Sometimes, you don't need anything at all —just align the wood figure properly in the joint to restrict the deformation. (See Figure 1-20.)

After designing a joint system that allows the wood to expand and contract and carefully aligning the wood figure in each joint, there is one more thing you must do to relieve the stress due to wood movement — apply a finish. A good finish slows the release and absorption of moisture, and prevents the wood from shrinking or swelling too quickly. This, in turn, protects the wood from radical changes in relative humidity that often occur several times a week — sometimes several times a day! The wood movement is slower and gentler, and the joinery lasts longer.

1-18 Because the annual rings run diagonally through the leg on the left, the wood will expand or contract to a diamond shape. This will pull the aprons out of alignment so they are no longer square to one another. If the aprons were attached at the other end, all the joints in the leg-and-apron assembly would be stressed. Not so with the leg on the right. Because the rings run side to side, the wood will expand or contract to form a rectangle. Although the wood does deform, the aprons remain properly aligned.

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Woodworking Tools and Installation Tips

Woodworking Tools and Installation Tips

There are a lot of things that either needs to be repaired, or put together when youre a homeowner. If youre a new homeowner, and have just gotten out of apartment style living, you might want to take this list with you to the hardware store. From remolding jobs to putting together furniture you can use these 5 power tools to get your stuff together. Dont forget too that youll need a few extra tools for other jobs around the house.

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