Abstract: A drill rig assembly adapted to be mounted on a vehicle and having a pivotal link assembly mounted to the vehicle. Attached in slidable relationship to the link assembly is a mast assembly containing feed means and rotary means fully enclosed within the mast assembly. An electronic level within the mast assembly automatically maintains the mast assembly in a predetermined, angular position. The drill rig assembly is capable of drilling either vertically or at selected, incremental angles. The drill rig assembly is designed to be safe in operation and lightweight, while providing performance characteristics of larger drill rigs.