A lance drive support apparatus is adapted to be fastened directly to a heat exchanger tube sheet adjacent a selected number of tubes to be cleaned. One embodiment includes an angled flat base plate having an inner center corner, an outer center corner, a first outer end corner and a second outer end corner, a support post adjacent each outer end corner, and the inner center corner fastened at one end to the base plate, and a top plate fastened to an opposite end of each support post. An extensible scissor arm assembly pivotally fastened to the inner center corner post can position a lance drive mechanism at a distal end of the scissor arm assembly at precise X and Y coordinates adjacent the tube sheet. The precise X and Y coordinates are determined by positions of X and Y cylinders connected to a common scissor arm assembly extension hinge.