The wedge, made of nickel chrome steel, is case hardened and ground on all the working surfaces. The base jaws also made of nickel chrome steel, are case hardened and ground to match both the wedge and the body guideways. The base jaws are guided in the deep, wide, hardened slots in the body, which provide the ample bearing area necessary to withstand the forces resulting from high gripping action. Provision has been made for manual lubrication of sliding Serrations are ground on the top face of the base. The serrations on the bottom to match the base jaws. The various radii on the hard jaws in conjunction with the serrations are designed to grip a wide range of diameters. hardened chrome case hardened and ground base jaws and the wedge ensure high load carrying capacity over a very long period.