An employee was adjusting the chains on a piece of equipment, preparing it to be lifted by an overhead crane. The coworker operating the crane let go of the control button for lowering the chains. The injured employee thought the crane had already come to a complete stop, so he attempted to adjust the chains. His left hand was on one of the chains and while adjusting the other chain with his right hand, the chain tightened and slapped against his left hand, amputating his left middle fingertip.