Trend 6200/8TC 6200/8 TCT Countersink Set. Choose TCT for abrasive materials. NOT SUITABLE FOR FERROUS AND NON FERROUS METALS. T.C.T. No.8 Wooscrew. These well proven adjustable countersinks are all supplied complete with an HSS twist drill and a hexagon key. They are designed to drill and countersink simultaneously a wide variety of materials. Diameter: 5/8in. Drill Diameter: 3/16in. Overall Length: 1.1/4in. Supplied with a HSS slow spiral drill bit. Fully adjustable, a hex key is supplied. The TCT version is used for plywood, particle boards and plastics (abrasive). Use at drilling speeds only. Not suitable for ferrous or non ferrous metals. Please ensure drill flutes are aligned with flutes of countersink.