This tool is useful for testing spindle run out of machine tools, lathe work etc. It is well adapted for inspection of the parallelism of surfaces. The indicator can be swiveled in all directions. The base is of steel and provided With T slots for convenience in clamping. The surfaces of the base are accurately ground. New clamping system ensures quicker rigid clamping even with moderate tightening. The holder for the dial indicator is equipped with fine adjustment device permitting vibration free adjustment to zero.