The Dormer Pramet A125 7.00 mm x 310 mm HSS ST STRAIGHT SHANK EXTRA LONG SERIES DRILL BS 328 is purpose-built for serious deep-hole drilling without compromise. Designed for professionals who demand reach, precision, and reliability, this drill bit pairs a robust high-speed steel core with a long, straight shank that fits a wide range of drill presses, milling machines, and CNC setups.

Key features that matter in real-world use

• 7.0 mm diameter with an 310 mm overall length for those deep-hole tasks where shorter bits would mean stops, resets, or tool changes.
• 118-degree conventional point creates a strong, self-centering starting edge that bites quickly and is easy to re-sharpen for long-term edge retention.
• Steam oxide finish reduces friction and prevents workpiece material from sticking to the cutting edge, aiding smoother starts and cleaner holes.
• Premium HSS material delivers resilience across a variety of metals, including steel, aluminium, and stainless steel, while maintaining cutting performance over time.
• Straight shank design ensures secure clamping and consistent runout on a broad range of tool holders, improving hole quality in precise applications.
• Extra long series enables reaching deep cavities, pockets, and through-holes where standard-length drills can’t reach, reducing the need for multiple tools on the job.
• BS 328 compliant build reflects a trusted, industry-standard specification for consistent geometry and performance.

Why this drill bit stands out for deep drilling

When you’re drilling deep holes, accuracy and control matter as much as speed. The A125’s extended length gives you the reach to penetrate through long workpieces or multiple material thicknesses in a single setup, minimizing tool changes and downtime. The 118-degree point minimizes wandering at start-up, which translates to straighter holes and less chatter, even when you’re working with tougher materials or less-than-ideal workholding.

Materials and use cases

Thanks to its premium HSS composition, this drill bit handles a broad spectrum of metals with dependable performance. It’s an excellent choice for:

• Drilling through thick steel plates or structural components where access is limited
• Creating deep pilot holes before tapping or reaming
• Working with aluminum sections in fabrication or hobbyist builds
• Through-holes in stainless steel assemblies that require a reliable, long-reach tool

Practical tips for best results

• Match the drill speed to the material and the bit diameter for optimal cutting efficiency; slower speeds for harder materials, higher speeds for softer metals.
• Use light, steady feeds to avoid deflection when starting a deep hole; consider a pilot hole to guide the bit if needed.
• Apply appropriate cutting fluid or lubricant to reduce heat buildup and extend edge life, especially on stainless steel.
• Securely clamp the workpiece and ensure proper workholding to maintain straightness throughout the drilling process.