In woodworking, there are two distinctly different categories of scarf, based on whether the joint has interlocking faces or not. A "plain" scarf is simply two flat planes meeting on an angle relative to the axis of the stock being joined, and depends entirely on adhesive and/or mechanical fasteners (such as screws, nails, or bolts) for all strength. "Interlocking" scarf joints, such as a hooked, keyed, and nibbed scarves, offer varying degrees of tensile and compressive strength, though most still depend on mechanical fastening to keep the joint closed.