DIN340 HSS Long Series Drill Bits

Long drill bits are engineered for deep-hole drilling where standard lengths cannot reach. In industrial manufacturing, they are essential for creating oil channels in engine blocks, wire routing through thick timber beams, and deep fastening points in structural steel. These bits are designed with optimized flutes to ensure that metal chips (swarf) are effectively evacuated from the depths of the hole, preventing overheating and tool breakage.

Significantly longer than jobber bits, designed for deeper reach while maintaining a balance between length and rigidity. At Tenyu Tool, our long series bits are manufactured from premium HSS, ensuring they maintain a Rockwell hardness of 63 HRC or higher even at extended lengths.

Absolutely. For extreme depth requirements, Extra Long (XL) drill bits (also known as aircraft extension bits) are used. These can range from 150mm to over 500mm in length. Because of their extreme length-to-diameter ratio, our extra-long bits undergo specialized vacuum heat treatment to enhance flexibility without sacrificing the cutting edge's hardness, allowing them to withstand the high torque required for deep penetration.

In the professional B2B tool market, longer drill bits are referred to by specific technical names based on their design: Long Series Drill Bits: General-purpose extended length. Aircraft Extension Bits: Originally for the aerospace industry, these have a standard flute length but a very long, non-fluted shank. Parabolic Flute Drills: A high-performance version of long bits with wider flutes for superior chip removal in deep holes.

Insert the drill bit into the chuck or spindle, ensuring it is properly aligned and tightened securely. For longer bits, maintaining straight alignment and stable clamping is important to reduce vibration and ensure accurate drilling.

To drill straight with a long drill bit, start by marking the hole center and creating a pilot hole to guide the bit. Keep the drill aligned vertically(90 degrees), use low speed with steady pressure, and avoid forcing the bit. For better accuracy, a drill press or guide jig can be used to reduce bending and vibration during drilling.