A chop saw is used to cut hard materials, such as metals and sheeting. The cutting action is performed by an abrasive disc, similar to a thin grinding wheel. The saw generally has a built-in vise or other clamping setup, and has the cutting wheel and motor mounted on a pivoting arm attached to a fixed base plate. They typically use composite friction disk blades to abrasively cut through the steel. The disks are consumable items, and wear throughout the cut. Chop saws have replaced more expensive and hazardous acetylene torches in many applications, such as cutting rebar.