Abstract: A clamping device (2) adapted to be used to grasp an article or to clamp a tool to a workpiece, comprising: (a) a substantially flat or curved vacuum chamber (21) having a lower surface contained or comprised in a vacuum body (14, 15); (b) a compressible seal (18) located at or adjacent the perimeter of the vacuum body, the compressible seal being located in a groove (19) in the vacuum body, the groove being so dimensioned that the compressible seal, when pressed against an article or workpiece, expands and/or moves into a space in the groove thus stabilizing the position of the compressible seal and improving its airtight qualities; and (c) a source of vacuum (23) for connection to the vacuum chamber.