Dormer Pramet A125 17/64 Inch x 250 mm HSS ST STRAIGHT SHANK EXTRA LONG SERIES DRILL BS 328

The Dormer Pramet A125 17/64 Inch x 250 mm HSS ST Straight Shank Extra Long Series Drill (BS 328) is built for serious metalworking where depth, precision, and reliability matter. This is a purpose-designed drill bit meant to tackle deep holes in a variety of materials without compromising accuracy or speed.

• 17/64" (approximately 6.75 mm) with a 250 mm overall length, featuring a straight shank for quick, secure clamping in standard chucks.
• 118° conventional point: A robust tip geometry that stays sharp, aids in starting holes cleanly, and is easy to re-grind when needed to extend tool life.
• Steam oxide finish: A low-friction coating that minimizes built-up edge and workpiece material adhesion at the cutting edge, helping to maintain a true hole and prolong edge life.
• Extra long length series: Specifically designed for drilling very deep holes and situations where reach is critical, without sacrificing rigidity or control at the point.
• Premium HSS material: High-speed steel is versatile enough for drilling a broad range of metals including steel, aluminium, and stainless steel, delivering dependable performance across projects.
• Versatile, reliable performance: The A125 is suitable for a variety of machines and setups, making it a go-to choice when depth, consistency, and compatibility are essential.
• BS 328 compliance: Engineered to meet standard specifications, ensuring interchangeability and predictable results in professional shop environments.

Why choose the A125 Extra Long Drill for deep-hole work

When your work requires drilling deep, straight holes with minimal wandering, the A125’s combination of a strong 118° point and a long reach delivers steady accuracy from the first pilot hole to the deepest cut. The steam oxide finish helps maintain clean cuts by reducing heat buildup and sticking, so you can push through tougher materials with less chatter. The straight shank ensures dependable seating in standard drill chucks, which translates to consistent hole alignment and less runout over long drilling cycles.

Ideal use cases

• Deep hole drilling in steel, stainless steel, and aluminum components found in fabrications, enclosures, and machinery frames.
• Workbench and machine-taught operations where extended reach is necessary to access recessed pockets, through-holes, or frames with obstructed entry points.
• Maintenance and repair tasks involving thick metal plates or assemblies where standard-length bits would require repositioning or relaying.
• Prototype and production environments where consistent hole quality and tool life are critical for workflow efficiency.

Practical tips for best results

• Use appropriate cutting fluid or lightweight lubrication when drilling steel to reduce heat and extend edge life.
• Start with a center punch to minimize wandering, then feed steadily to maintain a clean entry and exit.
• Maintain a steady drill speed and moderate feed pressure; for stainless steel or harder alloys, reduce RPM to control heat buildup.
• For very deep holes, consider stepping with a pilot hole first, then switching to the A125 for the final depth to improve stability and hole quality.
• Inspect the flute clearance and re-sharpen or replace when the edge dulls to preserve hole accuracy and surface finish.

What you’ll achieve with the Dormer Pramet A125 drill is predictable, repeatable hole quality in demanding deep-hole applications. Its 17/64" diameter suits many mechanical assemblies, while the 250 mm reach expands your capabilities in constrained work envelopes. The combination of 118° point geometry, steam oxide finish, and premium HSS delivers a reliable tool that resists buildup, maintains edge life, and reduces downtime caused by tool failure.

The included brand imagery reflects the trusted Dormer Pramet lineage that backs this drill bit with decades of machining expertise and a focus on precision and durability in metalworking environments.