The Dormer Pramet A125 10.50 mm x 250 mm HSS ST STRAIGHT SHANK EXTRA LONG SERIES DRILL BS 328 is engineered for deep-hole reliability and versatile metalworking performance. With a precise 10.50 mm diameter and a substantial 250 mm overall length, this drill delivers extended reach without sacrificing rigidity or control in the cut.

Key features that matter in real-world drilling

• 118-degree conventional point provides a strong, self-centering bite and is straightforward to re-grind when the edge eventually dulls, helping you extend tool life between changes.
• Steam oxide finish minimizes material adhesion to the cutting edge, promoting cleaner holes and reducing built-up edge during high-pressure drilling tasks.
• Extra long length (250 mm) designed for drilling very deep holes, step-downs, or accessing recessed workpieces where shorter bits can’t reach.
• Premium HSS material delivers dependable wear resistance and toughness across a range of common engineering materials, including steel, aluminium, and stainless steel.
• Straight shank ensures stable guidance in standard chucks and collets, reducing runout and delivering consistent hole quality on every plunge.
• BS 328 compliant designation aligns with industry-standard sizing, making it a dependable choice for workshops that rely on interchangeable tooling.

Ideal use scenarios

Performance tips for best results

• Pair this drill with appropriate speeds and feeds for the material being machined; as a guideline, start at conservative speeds and increase gradually while monitoring chip formation.
• Use a compatible cutting fluid or coolant to dissipate heat during deep drilling, helping extend tool life and improve hole finish.
• Begin with a pilot hole if the workpiece is prone to wandering, then advance with the 10.50 mm bit to maintain concentricity and reduce deflection.
• Keep chips clear and avoid forcing the drill; a steady, consistent feed rate yields cleaner holes and helps preserve the tip geometry for longer.

Whether you’re outfitting a general machine shop or tackling a specific depth-limited project, the Dormer Pramet A125 10.50 mm x 250 mm HSS Straight Shank Extra Long Drill is built to deliver consistent hole quality, extended reach, and dependable performance across common metals. Add it to your toolkit for a true deep-hole solution that doesn’t compromise on rigidity or versatility.