Abstract: A guide mechanism and a portable drill are coupled together to define a portable, hand-operated drilling device. The drilling device includes a replaceable back-up fixture for engaging a first side of a workpiece and a drill support which adjustably and releasably engages a drill. The back-up fixture and drill support are mountable on opposing jaws of a manually operated tool of the type where the jaws may be closed by application of compressive force to a pair of handles.