A clamp comprising a bar supporting a movable jaw having a first support surface. The bar is slidably received in a jaw body and the jaw body supports a fixed jaw. A support is slidably disposed on the bar and has a second support surface that is coplanar with the first support surface such that the clamp can be supported on the first support surface and the second support surface on a surface. In one method of operating the clamp a work piece is positioned directly on the bar. In another method of operating the clamp the movable jaw is moved relative to the fixed jaw and is stopped by the engagement of the support with the body.