A dowel is a short, round wooden or plastic pin used as a fastener between two workpieces. A hole is drilled on each side, the dowel is inserted with glue into one hole and the other workpiece is pressed onto it. Dowels are a simple, invisible joining method.
How does it work?
1. Drill a hole in workpiece A to match the dowel diameter
2. Drill a hole in workpiece B at exactly the same position
3. Insert the dowel (with glue) into workpiece A
4. Press workpiece B onto the dowel
5. Clamp until the glue has cured
The dowel provides:
- Alignment — The workpieces cannot shift
- Strength — The dowel increases the glue surface area and resists shear forces
- Invisibility — Nothing is visible on the outside
Dimensions
| Dowel diameter | Suitable for wood thickness |
|---|---|
| 6 mm | Up to 15 mm (thin boards, mouldings) |
| 8 mm | 15-25 mm (furniture panels, boards) |
| 10 mm | 25-40 mm (solid wood, heavier joints) |
| 12 mm | 40+ mm (structural woodwork) |
Rule of thumb: the dowel diameter is roughly 1/3 of the wood thickness.
Standard dowel length: 30-40 mm (half sits in each workpiece).
Types of dowels
Wooden dowels (fluted)
- Standard dowel with flutes for better glue adhesion
- Made from beech or birch (hard, smooth)
- Cheap and widely available
Plastic dowels
- Not glued but click into place
- Used in flat-pack furniture (IKEA-style)
- Less strong than glued wooden dowels
Domino dowels (Festool)
- Flat, oval-shaped dowels
- Require a Festool Domino joiner
- Very strong and quick to assemble
Placing dowels — tips
Accuracy is everything
The biggest problem with dowels: the holes must line up exactly opposite each other. Aids:
- Dowel centres — Small metal pins you insert into one hole, press the other workpiece onto them and mark the hole position
- Dowel jig — A drilling template clamped to the workpiece
- Joiner machine — Festool Domino or similar
Basic rules
- Drill the hole 1-2 mm deeper than half the dowel length (room for glue)
- Use a depth stop on the drill
- Always drill perpendicular to the surface
- Apply glue in the hole, not on the dowel (prevents glue being pushed out of the hole)
Related terms
- Mortise-and-tenon joint
- Half-lap joint
- Tongue and groove