Meet a purpose-built deep-hole drilling ally: the Dormer Pramet A125 5.50 mm x 310 mm HSS ST Straight Shank Extra Long Series Drill BS 328. This precision tool is engineered to tackle long reach projects with confidence, delivering reliable performance from first cut to final depth.

Key features that matter on the shop floor

• 118 degree conventional point for a strong, self-centering start that’s easy to re-sharpen, reducing downtime and preserving cutting edges between uses.
• Steam oxide finish minimizes workpiece material adhesion to the cutting edge, helping chips flow freely and reducing built-up edge during demanding drilling sessions.
• Extra-long length (310 mm) designed for drilling very deep holes or situations where reach matters—perfect for fabrication, automotive assemblies, and challenging workpiece geometries.
• Premium HSS material capable of handling a wide range of materials, including steel, aluminum, and stainless steel, without compromising toughness or edge retention.
• Straight shank provides broad compatibility with common drilling machines and tool holders, ensuring stable performance across various setups.

Designed for real-world use

Whether you’re drilling through metal plates, frames, or components with limited access, this drill delivers consistent hole quality and straightness. The A125 geometry is tuned for dependable starts and clean perforations, reducing the need for rework. Because it’s an HSS twist drill with a long, straight shank, it pairs seamlessly with drill presses, mill/turn centers, and handheld drilling rigs alike.

Ideal use cases

• Deep-hole drilling in steel, stainless steel, and aluminum components where conventional-length tools fall short.
• Fabrication and assembly work in automotive, aerospace, and general metalworking shops requiring extended reach.
• Maintenance and repair tasks that demand a reliable, long-reach drill without changing tooling mid-project.
• Situations where a durable, re-sharpenable point reduces downtime and extends tool life between dressings.

Practical tips for best results

• Match cutting speed and feed with the material being drilled; start with a light, controlled engagement to seat the point and prevent wandering.
• Use a light cutting fluid or coolant to manage heat buildup, especially when drilling stainless steel or other hard materials.
• Peck drilling and occasional chip clearing are recommended for deeper holes to maintain cutting efficiency and prevent clogging.
• Secure the workpiece firmly and ensure proper alignment to maximize hole accuracy over the 310 mm reach.