Abstract: A clamping device for use in clamping dial indicators and like instruments used in surveying comprises a bifurcated clamping element having a pair of elongate arms defining a central slot. The arms define a pair of circular openings at the base of the slot, a large circular opening midway up the slot, and rebates defining a seat for a dovetail key at the end of the slot. An adjustment screw is provided between the arms for tightening of same. A variety of split sleeve inserts having different internal diameters may be used in the large circular opening for receipt of different size instruments.