Abstract: A cutter wheel is mounted at the lower end of the machine for rotation about a horizontal tubular support. Cuttings are picked up by buckets on the cutter wheel and are directed into the tubular support to be received by an endless bucket conveyor which carries them upwardly to a discharge station. As the machine is advanced the cutter wheel is rotated to make a first cut in the shape of the leading portion of the cutter wheel. The cutter wheel is then retracted out from the cut and is rotated about the axis of the hole. This repositions the cutter wheel so that when it is advanced again it will make a second cut which crosses the first. This procedure is repeated until the desired cross-sectional configuration (e.g. circular) of the hole is obtained.