Snappy HSS Drill Bits are gripped by a spring steel collet into Hex Shaft. The Hex shanks snap into the quick chuck. The HSS Drill Bits in this 7 piece set are gripped by a spring steel collet into the hex shaft. The hex shanks snap into the Quick Chuck. Contents. 1.6 mm (1/16in) Drill. 2.4 mm (3/32in) Drill. 3.2 mm (1/8in) Drill. 4.0 mm (5/32in) Drill. 4.8 mm (3/16in) Drill. 5.6 mm (7/32in) Drill. 6.3 mm (1/4in) Drill. With collets.