Zentrierbohrer

A Zentrierbohrer, or center drill bit, is a short drill used in metalworking to produce a small, accurately centered starting hole for subsequent drilling and to establish a true center for lathe operations. The bit combines a small pilot drill with a larger conical portion, typically forming a 60-degree center point that helps locate the workpiece and guides the following drill.

Design and materials vary, but Zentrierbohrer are usually made from high-speed steel (HSS) and come in two main form factors: stub (short) center drills for high rigidity in turning operations, and longer versions for deeper work or difficult setups. Some variants are carbide-tipped for increased wear resistance in production environments. They are available in a range of pilot diameters and overall lengths to suit different materials and machine capacities.

Usage and purpose: in a lathe, the Zentrierbohrer is mounted in the tailstock and advanced into the workpiece while it is held between centers or supported by a chuck. The initial pilot hole centers the bit and reduces drift, while the 60-degree cone creates a precise center point that can align with a live or dead center. This improves hole concentricity, reduces drill wandering, and provides a solid starting point for deeper drilling or turning operations. Coolant is often used to prolong tool life and improve finish.

Variations and considerations: center drills are designed specifically for starting holes and are not intended for through drilling. They are chosen based on the required starting hole size, material, and depth. In some workflows, a separate pilot drill followed by a standard drill may be used instead of a center drill.