Montalvo’s GRAA is a maintenance free, heavy duty mechanical core chuck capable of handling very high roll weights. It is engineered to use the side force pressure of machine arms to expand and grip the core. As the core presses against the core stop flange on the outer housing of the chuck, the outer housing moves back and the lugs or leaves expand with absolute concentricity. The chuck can only expand when the core hits the flange, as the outer nose is part of the inner body. Available with Adapters or in a Step Design for quick change to larger core sizes ranging from 3″ to 16″.