Inter-locking joints in wood
In this small guide, we will show how you can make wooden joints that are both stable and glue-free. There are different ways to do it and the best solution depends on how soft the material is and how much it varies in thickness. It is often easiest to knock the parts together with a rubber hammer. The examples below are made in 3mm birch plywood.
The first method is with a single short arc in the middle of the joint, as shown in the drawing below.
In the second method, we use a longer arc, still in the middle of the joint. A longer arc gives a tighter result than the short one.
An even tighter fit can be achieved with the third solution: 2 short arcs divided across the joint. If you have very long joints, it can be a good idea to make the arcs longer.
If you have to make many joints or mass produce a product, it is a good idea to test different joint solutions in the material before finalising your design. Test the joints in the sizes you need in your final design to get a realistic idea of what works best.