Biscuit Dowels (Lamello): Wood Joining System, Sizes (0, 10, 20) & Application
A biscuit dowel (frequently referred to as a Lamello after its inventor) is an oval-shaped timber joining element made from compressed beech wood. It is inserted into a precisely routed groove and is used for the butt-joint gluing of sheet materials or solid timber. Upon contact with water-based wood glue, the material swells to create an extremely resilient, positive-locking joint.
What Exactly Is a Biscuit Dowel?
In professional furniture construction and joinery, the biscuit dowel is a standard fitting for concealed timber joints. It consists of beech wood compressed diagonally to its longitudinal grain. This specific grain orientation ensures high breaking strength under load. Installation requires a dedicated biscuit jointer, which cuts an exact 4 mm wide groove into the workpieces to be connected.
The mechanical principle functions like an invisible anchor within the wooden panel: as soon as wood glue (typically PVA glue) is applied, the compressed timber absorbs the moisture, expands in thickness by fractions of a millimetre, and wedges itself permanently into the routed slot.
Biscuit Dowel Sizes and Dimensions in Detail
The standard thickness of all classic wooden biscuits is exactly 4 mm. Selecting the right size depends on the material thickness of the chipboard or solid wood used. The three most common industrial sizes for furniture construction are 0, 10, and 20:
- Size 0:
- Dimensions: 47 x 15 x 4 mm
- Required routing depth: 8 mm
- Application: For narrow frame joints or thin material thicknesses (from 10 mm board thickness).
- Size 10:
- Dimensions: 53 x 19 x 4 mm
- Required routing depth: 10 mm
- Application: The standard for medium material thicknesses (from 13 mm to 15 mm). Ideal for delicate carcasses or when fitting accurately aligned drawer systems.
- Size 20:
- Dimensions: 56 x 23 x 4 mm
- Required routing depth: 12 mm
- Application: Maximum stability for standard cabinet panels (from 16 mm board thickness, typically 19 mm). Used in large wardrobes and heavy carcasses.
Practical Use and Installation
The decisive technical advantage over a classic dowel pin is the lateral tolerance during assembly. The routed groove is always slightly longer than the biscuit dowel itself. As a result, the workpieces can still be shifted lengthwise by a few millimetres while gluing to align them completely flush. This lateral play forgives minor marking inaccuracies.
To achieve optimal strength, glue is applied both inside the routed slot and onto the mating surfaces. After assembling and aligning, the components must be clamped securely until the glue has set and the biscuit dowel has fully expanded inside the joint. This not only secures the outer carcass, but also permanently stabilises internal load-bearing elements such as integrated drawer systems against shear forces.
Related Terms
- Dowel pin: A cylindrical wooden pin which, unlike the flat biscuit variant, permits no lateral adjustment during assembly.
- Cam lock connector: A demountable metal connecting fitting, frequently used instead of glued biscuits for flat-pack furniture.
- Biscuit jointer: The power tool that creates the precise slot for the connector using a circular blade (usually 100 mm diameter).
Matching Category
For the professional construction of stable furniture projects, you will find standard biscuit dowels in industry-standard sizes 0, 10, and 20 within our fittings range.