How do you frag a green hammer?

cutting a branch off form the main colony with bone cutter usually works well.

Using bone cutter will crush the skeleton if it is weak. I would use a dremmel with cutting wheel. Wear safety glasses. Remove the coral from the tank in the upside down position shaking it to close the polyps before you remove it from the water. Then place on a towel and slice on branch off. Then return to tank.

See this thread...http://www.aquariacentral.com/forums/showthread.php?t=93238