A workpiece drilling machine includes to be moved to any of several drilling locations along the workpiece. A plurality of indexing detents is formed along the rail coinciding with each drilling location. A cam follower on the drill carriage is engageable with the detents to coarsely position the drill carriage. An index-cancelling device is associated with each detent and controllable by a preprogrammed input device to determine which of the detents is to be available for engagement by the cam follower. The programmed input device has a visual marking thereon corresponding to the information encoded therein and a visually perceptible status readout is controlled by the index-cancelling means to permit visual verification that the index-cancelling devices are arranged in accordance with the desired pattern. An accurately positioned bearing is located at each drilling location and is engaged by a fine-positioning pin mounted on the drill carriage prior to the start of drilling to provide fine positioning of the drill carriage. A workpiece locator device is included that allows the workpiece to be positioned in one of several discrete positions relative to the rail. A clamping system located in the drill carriage clamps the workpiece in position referenced to the drill carriage to eliminate the effects of warp and twist in the workpiece on hole location.