What is a dowel joint?
A dowel joint is a butt joint reinforced with wooden pegs. A well-made dowel joint is as strong as a mortise and tenon joint. It is often used instead of the mortise and tenon joint if cost is a consideration in the assembly of the work. Dowel holes must be a perfect 90 degrees to the face of the work or the dowel will twist when it is assembled.
What are the advantages of this type of joint?
Neat strong joint, providing you use strong glue
Simple, quick and easy to make
What are the disadvantages of this type of joint?
Drilling accurate holes can be difficult
What are the applications for this type of joint?
Used to join frames, boxes, cabinets, carcases, and boards edge-to-edge or at right angles to each other. Most factory-made furniture has dowel joints, even for chair rails, which have to resist prolonged and considerable strain.
Types of dowels:
Readymade dowels are available to buy pre cut to sizes. They are made from tough, strong, crack/split resistance and short grained woods like beech, birch and maple. They are designed chamfered at either end to make them easier to insert. They also have shallow glue slots, also known as grooves or flutes, machined lengthways down their sides to increase the glue area, allow space for the glue and allow air and surplus glue to escape when the dowel is tapped in. If the air and surplus glue were not allowed to escape from the glue hole as the dowel was being tapped in, there would be a build up of hydraulic pressure, which would cause the wood to split.
If you only need a few dowels, cut them from a length of dowel rod, steady the dowel rod on the bench hook and cut off short sections with a fine-toothed saw (dovetail saw). To avoid breakout of the wood fibres, rotate the dowel rod as you cut. Chamfer the end of the dowel with a file and cut a single glue slot. Dowels are cut a little short of the drilled hole to give the glue space and to ensure a 'fit'.
Types of dowel joints:
Dowelled butt joint
This style of butt joint is the simplest of all methods of joining two pieces wood together. However the strength of the joint relies entirely on the glue and any additional fixings such as screws, pins, nails, tongues, biscuits, corner blocks or in this case the dowels used to strengthen, reinforce and hold the wood together.
Dowelled mitred butt joint
A mitre joint is a form of decorative butt joint which no end grain is visible. A mitre halves the angle between the parts being joined. It is normally cut at 45 degrees, but different angles can be used for non square frames. The joint is usually reinforced with pins, nails, or in this case dowels to improve its strength.