Deadman (Sliding Deadman)

A deadman is a vertical support, often mounted to slide along a track under a workbench, used to brace the far end of a long board or panel that a bench's face vise alone can't fully support -- planing or working the middle of a long board with only one end held by the vise otherwise leaves the far end unsupported and free to flex or vibrate. Sliding along its track and often fitted with an adjustable peg or notch, a deadman can be repositioned to support stock of different lengths rather than being fixed at one spot.