Dormer A100 series general purpose 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: 1/4in. Working length: 63mm. Overall length: 101mm. Dormer A100 Hss Jobber Drill Bit 1/4In Ol:101Mm Wl:63Mm in Black