Timber Joints - Box
It is often required to build timber boxes in diy and there are a number of simple joints which can be used to make them. Do not just think of a box as a box, they are the basic form for drawers, cupboards and larger pieces of furniture both free-standing and built in.
The area of contact for this basic of all joints is limited to the end of the one piece of timber that butts against the surface of the second piece. It is the weakest type of joint, but is the easiest to make.
The butt joint can be strengthened by fitting a block of timber within the corner either just glued or secured into each side. Strengthening blocks are usually either triangular or square, the triangular blocks tend to have a larger surface area to each side for gluing purposes and look neater. These blocks can be used to strengthen any of the box joints shown on this page.
The shared area of contact is increased by joining one piece of wood to a rebate cut out of the end of one piece of timber at a corner. This type of joint construction also allows nails or screws to be used on both pieces at right angles to each other, creating an even stronger joint.
The edge of the rebate is marked on the appropriate piece of timber and the depth is also marked around the sides and end. The edge should be cut down to the required depth with a tenon saw and the surplus material removed using a chisel or a router set to the appropriate depth. The depth should be cut twice, the first time to remove the bulk of the material, the second time to carefully take it down to the correct level.
A channel is cut into one piece of wood so that a second piece of wood fits into it. The channel should be no deeper than one-third of the thickness of the piece of wood. The amount of timber to be left between the channel and the end, should be at least the width of the channel.
Many drawers are constructed with housing joints as they withstand stress from several directions.
The sides of the housing channel are marked on the appropriate piece of timber and the depth is also marked on both edges of the timber. The sides should be cut with a tenon saw and the surplus material removed using a chisel or a router set to the appropriate depth. The depth should be cut twice, the first time to remove the bulk of the material, the second time to carefully take it down to the correct level.
For a mitre joint, the ends of two pieces of wood are under cut at a 45 degree angle. The mitre, which is only marginally stronger than the butt, is used widely for appearance sake as the joint conceals the exposed end grain of both pieces of timber.
They require precision 45 degree cuts so that the right angle can be accurately made, it is recommended that the angles are cut using a power circular saw with a suitable guide of jig for accuracy. Using a Jig Saw or handsaw are liable to produce some inaccuracies which will ruin the visual appearance and give a weak joint as the adjacent pieces of timber will not fit very well.
- Decide upon the 'presentation face' of each piece of timber - it may not matter which face this is but you need to make all depth measurements from the same side of the finished box.
- Mark out all the joints before you start any sawing.
- Always cut on the waste side of the marked line.
- Measure twice (or thrice) and then cut accurately once.
- Use glasspaper to smooth each joint and remove any splinters.
- Assemble the joints using a good quality wood adhesive; apply it to all mating faces. Wipe away any surplus adhesive before it dries.
- Where the thickness of the timber allows, secure each joint with a nail or two, drive them in at an angle so they lock the timbers together.
- Clamp or apply pressure to each joint until the adhesive has dried, in humid conditions allow additional time.