Dormer A125 Series HSS Twist Drill Bit, 4mm Diameter, 315 mm Overall

High Speed Steel extra length drill for general machining applications.

Ideal for long reach applications and for drilling deeper holes by interrupted drilling (pecking)
Steam tempered finish improves wear resistance
Capable of drilling holes up to 10x diameter in most materials

BS 328

HSS Long & Extra Long Series

These HSS straight shank, right hand cutting long series twist drills are capable of drilling up to 10x the drill diameter before the flute needs to be cleared, to avoid fouling. They are made to BS328/DIN340 RN and ISO standards, and are recommended for use with steel and cast iron.