Add unbalanced mass to the surface of any rotating machine element and you present a challenge to the element's bearing system. That was the situation facing Agfa Corp. designers working on external drum plate-setters for a web-type printing press. They needed a clamp to hold down the flexible aluminum printing plate that wraps around the 4-ft wide, 1-ft diameter roll. Their problem: with the roll spinningat 300+ rpm, any excess mass in the clamp would create centrifugal forces that would strain the roll's journal bearings, eventually causing it to wobble — and the platesetter to improperly image.