Joining wood
There are in two different means of joining wood 鈥 permanent and non-permanent. Traditional construction features permanent fixing with glue and also a mechanical fastening such as screws, pins or nails. When a a more decorative finish is required, glue is used in combination with a more sophisticated joint.
More modern furniture with manufactured boards will use knock-down fittings so that parts can be easily replaced or flexibility in the modular construction and aesthetic of the items.
Glue is a chemical mixture that bonds wood surfaces together. The most common version of this is PVA (Poly Vinyl Acetate). It is very easy to apply and easy to clean off with water.
Pins are a metal fastening that is driven into two pieces of wood to connect them. The pins can be hammered or driven below the surface of the wood so that they can't be seen.
Nails are a thicker version of pins. They typically have a large striking surface so that it can be driven into the material.
Screws, like nuts and bolts, are a metal fastening that connects two bits of material together. Screws do this by carving a thread into the material that holds them secure. Unlike nails and pins, screws can be easily removed.
Knock-down fittings (KD fittings) are mechanical fixings generally associated with flat-pack furniture that allow for easy assembly and disassembly. They are mass produced and cheap and can come in many different forms. Knock-down fittings also make the construction simple as it reduces the need for specialist tools or experience for assembly.