Dormer Pramet A125 9/16" x 310 mm HSS ST Straight Shank Extra Long Series Drill BS 328 is engineered for precision when the hole goes deep and the material gets tough. Designed with an extra-long reach, this drill bit pairs a robust HSS core with a standardized straight shank, making it a reliable workhorse for challenging drilling tasks in metal shops, fabrication shops, and automotive environments.

• 118° conventional point — a sturdy, self-centering tip that bites cleanly on first contact and remains easy to re-sharpen, reducing downtime between jobs.
• Steam oxide finish — a friction-reducing coating that minimizes material sticking to the cutting edge, helping to extend tool life and deliver smoother holes.
• Extra long length — 310 mm overall length provides exceptional reach for drilling very deep holes, long through-holes, or work in recessed or crowded areas where standard bits can’t reach.
• Premium HSS material — versatile across a wide range of materials, including steel, aluminum, and stainless steel, while maintaining a dependable cutting action in tougher alloys.
• Straight shank design — optimized for secure seating in common drill chucks and fixtures, ensuring stable guidance and minimal runout during deep drilling.

This drill bit is ideal for machinists, fabricators, and technicians who regularly tackle long through-holes, dowel holes, or cavities where depth matters. Use in drill presses or high-speed hand drills with appropriate feeds and speeds to maintain cutter life and hole quality. For best results, pair with moderate cutting fluids to manage heat and chip evacuation, especially in steel and stainless steel applications.

Key specifications

• Diameter: 9/16" (0.5625")
• Overall length: 310 mm
• Shank: Straight
• Point angle: 118° conventional
• Finish: Steam oxide
• Material: High-speed steel (HSS)
• Applications: Drilling steel, aluminum, stainless steel, and other common metals