Abstract: Drill apparatus, especially for drilling glass, with hydraulic and/or mechanically advancing, driven drill spindle, wherein the drill spindle is secured in a spindle carrier and is equipped at the end which is facing towards the workpiece with a drill, as well as being equipped with a countersink or the like drill which generally surrounds the drill, whereby the drill and the countersink drill are axially adjustable with respect to one another, in accordance with the preceding wear. The drill is connected in a drill carrier by way of adjustment threads. An automatic adjustment device is provided for the drill in the drill spindle, which adjustment device includes a mechanical, forward and reverse step motion device with a screw-type guide, and a hydraulic cylinder/piston actuating assembly for the step motion device. The hydraulic cylinder/piston actuating assembly can be supplied with hydraulic pressure medium through the drill spindle carrier and additional passages.