Abstract: A boring bar system sized and configured for removable in-situ placement within a cylindrically-shaped worksite, such as a hydro turbine-powered dam. The system configured for use in inspecting or maintaining a fixedly and non-removably located work surface at the work site comprises a boring bar. The boring bar includes a vertically oriented rotating main shaft, a pair of stationary spiders, a pair of supports, and a tool arm. The tool arm contains a tool and a variety of mounting locations, or machine slides, to selectively vertically and radially position the tool. The system further comprises a drive control unit (DCU) configured to rotate the main shaft using a drive unit and a variable control drive logic that continuously alters a frequency of the DCU to produce a non-uniform pulsation of the drive unit. As the DCU rotates the main shaft, the tool contacts the work surface.