Screwsinks are used for drilling, countersinking and counter-boring in one operation. The countersinking part can be slid up and down the drill part of the tool by means of a hexagon key to suit the depth of hole being drilled. To ensure an accurate fit we suggest you use the corresponding plug cutter from the Faithfull range. Each screwsink is supplied with a hexagon key. The set of 4 Contains sizes 6 (7mm), 8 (8mm), 10 (10mm), and 12 (11.5mm). Description: Pilot Drill Set (4) for Screwsinks No: Size mm: