There are a few ways to attach metal to wood without screws, the most common of which is glue. You can use any glue that works with the materials you’re using, but some glues work better than others.  For example, epoxy is a strong glue that can be used almost anywhere, making it a good choice for attaching metal to wood. Gorilla Glue is another option that works well on a variety of surfaces, and it’s especially good for bonding uneven or porous surfaces.