Scarf joints utilise long, angled glue surfaces to maximise holding power when gluing wood together end-to-end. Scarf joints can be found on beams or any woodworking project where wood is joined lengthwise. The strength of a scarf joint comes from long diagonal cuts that run down the sides of the wood. The cuts are made freehand with a band saw and mated together with glue and clamps. Scarf joints must be done individually and are custom cut each time.
Lay two pieces of wood flat. Measure down 6 inches from one corner on one piece with a tape measure and make a mark with a pencil. Lay a ruler on the opposite corner on the same end and angle it down to the mark. You should be looking at a sharp point drawn on the wood approximately 6 inches long.
Cut the angle out on a band saw. Lay the angled board down on top of the other board and trace the angle onto it. Cut the other board at the same angle.
Spread glue on both angles. Place the angles together.
Place clamps 2 inches apart the length of the angles and tighten until glue oozes out and the angles are tight together. Let the glue dry for a minimum of one hour.
Remove the clamps and scrape off the residual dry glue with a glue scraper.
The measurements here are for examples. You can make any length of scarf joint on any size of wood.
Use a damp cloth to wipe up wet glue before it dries. Always wear safety glasses when working with wood.