Abstract: Disclosed is an apparatus, system, and method for precisely placing holes or attaching sub-components to vertical mullions or other workpieces of various shapes and material compositions. The apparatus, in its basic mode of operation, can accurately locate the positions of holes or groupings of holes to be drilled in the workpiece by means of the calibrated positioning, along the workpiece, of a plurality of fixtures affixed to specially-designed drill guide plates. When used in its advanced mode of operation, the fixtures of the apparatus are re-configured and loaded with a plurality of shear blocks or other connectors, and thereupon an operator, by calibrated placement of the fixtures, may simultaneously pinpoint the required fastening location of the shear blocks and sequentially attach specified fasteners through each shear block, directly onto the workpiece.