Dormer A170 HS 1/2in Parallel Shank Drill 20mm DOR2000 Standard helix, right hand spiral, ½in parallel shank drill, often referred to as a blacksmiths drill. General purpose drill, ideal for a wide range of materials where chuck holding capacity is limited. Suitable for both hand and machine use.WARNING:- For general purpose light-duty work only. Fracturing of the drill shank may occur if it is used for any other purpose or if extreme pressure is exerted on the drill.Size. 20mm DOR2000