Somta Extra Long Series Drill - 9mm x 250mm, HSS-E Parabolic Flute

Designed for serious deep-hole work, this 9mm diameter drill bit pushes the limits of reach with its generous 250mm length. The Extra Long Series is built to bore clean, accurate holes where standard bits simply can’t reach, making it an essential tool for long through-holes and deep blind holes in metal workpieces.

HSS-E construction delivers outstanding durability and heat resistance under demanding drilling conditions. The alloyed High-Speed Steel-E formulation extends tool life, maintains sharp cutting edges, and supports reliable performance across a range of metals and alloys encountered in professional machining and fabrication environments.

Parabolic flute geometry is the standout feature for deep-hole reliability. Its optimized chip evacuation path minimizes clogging and chip packing, which reduces dwell time and allows steadier feeds. That means smoother hole creation, less friction, and cooler operation—even when drilling deep into tougher materials.

The cutting edges are engineered to stay sharp longer, producing holes with clean entrances and precise diameters. The flute profile also helps manage heat build-up, preserving hole quality and extending the life of the drill in repetitive deep-hole drilling cycles.

Ideal use scenarios include long steel, aluminum, and other metal workpieces where hole depth exceeds standard tool lengths. Whether you’re machining engine blocks, fixtures, or long structural components, this drill bit delivers dependable penetration and consistent hole geometry across multiple passes and setups.

Practical tips for best results:

• Start with a steady, moderate feed to establish a clean cutting action before increasing depth.
• Maintain ample chip clearance—the parabolic flute design excels when chips are allowed to evacuate freely.
• Use appropriate lubrication or cutting fluid to reduce friction and prolong edge life during deep-hole operations.
• Secure your workpiece firmly to minimize deflection, especially when drilling through long sections or through-holes.