a reconfigurable fixture for workpieces is disclosed . it utilizes a flat surface magnetic chuck with modular workpiece supporting , locating and clamping elements that are carefully located on it and held by magnetic attraction to it . these elements are precisely located to hold the workpiece in spaced relation to the chuck surface . some locating elements are mechanically fixed to the chuck for securing the workpiece from transverse movement on the chuck surface . preferably , each of the supporting , locating and clamping members are fixed to separate steel bases for magnetic attraction to the chuck . each base may also carry its own hydraulic actuator for height adjustment of a support element or for height adjustment and closure of a clamping element . these modular elements can be selected from a storage magazine and located on a chuck by numerically controlled mechanisms .