A fishtail clamp is a type of woodworking clamp used to hold pieces of wood together during construction or woodworking. The clamp consists of two wooden jaws, typically made of hardwood, that are attached to a steel or brass screw. The jaws of the clamp are shaped like the tail of a fish, with a wide base that tapers down to a narrower point. This allows the clamp to be used on a range of different sized workpieces, as the narrow point can fit into tight spaces while the wider base provides a secure grip on larger pieces. To use a fishtail clamp, the jaws are first positioned on either side of the workpiece to be clamped, with the narrow point of each jaw aligned. The screw is then turned using a handle, which draws the jaws together and applies pressure to the workpiece. The jaws can be adjusted as needed to apply pressure evenly along the length of the workpiece. Fishtail clamps are commonly used in furniture making and other woodworking applications, particularly for securing joints while glue sets. They can also be used to hold pieces of wood together during drilling, sanding, or other finishing processes.