Dormer DORA100030 A100 HSS Jobber Drill Bit 0.30mm OL:19mm WL:3mm Dormer A100 Metric HSS jobber drills are suitable for use in the majority of general purpose engineering applications. They have good self-centring capability on a wide range of materials and are suitable for both hand and machine use. DIN338RN BS328 ISO235 Tip diameter: 0.30 mm. Working length: 3mm. Overall length: 19mm.