AIRCORE DRILL HEADS Hydraulic Contracting & Supply design and manufacture Air Core Drill Heads to suit customers requirements. Maximum Speed 230 RPM Torque 1800 @ 210 bar Larger Heads Available See below for Air Core Drilling Description. AIR CORE DRILLING Air core drilling and related methods use hardened steel or tungsten blades to bore a hole into unconsolidated ground. The drill bit has three blades arranged around the bit head, which cut the unconsolidated ground. The rods are hollow and contain an inner tube which sits inside the drill rod. The drill cuttings are removed by injection of compressed air into the hole via the annular area between the inner tube and the drill rod. The cuttings are then blown back to surface up the inner tube where they pass through the sample separating system and are collected.