Simple joints in woodwork and joinery
It’s often thought that only elaborate joints give good results in woodwork. It isn’t true. There are simple ways to join timber, and one of the simplest is the butt joint. It’s easy to make, can be used on natural timber or man-made boards, and it’s neat. What’s more, given the right adhesive and the right reinforcement, a butt joint can also be strong enough for most purposes.
The great thing about butt joints is their simplicity. You can use them on any kind of timber or man-made board, provided it isn’t too thin – not under 6mm. The only problem you will run into is where you are joining chipboard. A special technique is needed here to get the screws to grip. Although it is possible to simply glue two pieces of wood together, unless you add some kind of reinforcement the result won’t be very strong. So in most cases, the joint should be strengthened with either screws or nails.
The question is which? As a rule of thumb, screws will give you a stronger joint than nails. The exception is where you are screwing into the endgrain of natural timber. The screwthread chews up the timber to such an extent that it has almost no fixing value at all. Nails in this case are a much better bet.
Choosing the right adhesive for carpentry
Even if you are screwing or nailing the joint together, it ought to be glued as well. London Carpenters Robuild use PVA woodworking adhesive, as it will do the trick in most jobs, providing a strong and easily achieved fixing. This type of adhesive will not, however, stand up well to either extreme heat or to moisture; the sort of conditions you’ll meet outdoors, or in a kitchen, for example. A urea formaldehyde is the glue to use in this sort of situation.
Choosing the right joint
There are no hard and fast rules about choosing the best joint for a particular job. It’s really just a case of finding a joint that is neat enough for what you’re making, and strong enough not to fall apart the first time it is used. And as far as strength is concerned, the various kinds of butt joint work equally well.
Marking timber
Butt joints are the simplest of all joints – there’s no complicated chiselling or marking out to worry about – but if the joint is to be both strong and neat you do need to be able to saw wood to length leaving the end perfectly square.
The first important thing here is the accuracy of your marking out. Examine the piece of wood you want to cut and choose a side and an edge that are particularly flat and smooth. They’re called the face edge and face side. Next, measure up and press the point of a sharp knife into the face side where you intend to make the cut.
Slide a try-square up to the knife, making sure that its stock – the handle – is pressed firmly against the face edge. Then use the knife to score a line across the surface of the timber. Carry this line round all four sides of the wood, always making sure that the try-square’s stock is held against either the face edge or the face side.
If you wish, you can run over the knife line with a pencil to make it easier to see – it’s best to sharpen the lead into a chisel shape. Why not use a pencil for marking out in the first place? There are two reasons. The first is that a knife gives a thinner and therefore more accurate line than even the sharpest pencil. The second is that the knife will cut through the surface layer of the wood, helping the saw to leave a clean, sharp edge.