These well proven adjustable countersinks are all supplied complete with an HSS twist drill & a hexagon key. They are designed to drill & countersink simultaneously a wide variety of materials. Choose TCT for abrasive materials. NOT SUITABLE FOR FERROUS & NON FERROUS METALS.T.C.T. No. 6 Woodscrew Diameter 1/2 in. Drill Diameter. 5/32 in. O/L 1.1/4 in.