Irwin Schlangenbohrer spiral drill 20 mm x 400 mm, 6‑mm hex shank 7.9 mm

Irwin Schlangenbohrer spiral drill 20 mm x 400 mm with a 6-mm hex shank and 7.9 mm shank thickness is a long-reach twist auger-style drill designed for deep-hole drilling in wood and comparable soft materials. The 20 mm cutting diameter and 400 mm overall length provide extended reach for drilling through panels, beams or creating blind holes where standard-length bits cannot reach. The 6-sided hex shank allows secure clamping in many hand-held drills and drill drivers equipped to accept hex shanks.

Advantages

The spiral flute design removes chips efficiently from deep holes, reducing jamming and heat build-up during extended drilling operations. The long 400 mm length enables access to recessed or hard-to-reach areas without requiring extensions or special tooling. A 6-mm hex drive minimizes slippage in the chuck, improving torque transfer for consistent cutting performance. The 20 mm cutting diameter offers a balance between hole size and structural integrity of the workpiece for common woodworking tasks.

Suitable for

• Drilling deep through-holes in timber, plywood and chipboard
• Creating blind holes in beams, joists and door frames
• Working in recessed or hard-to-reach areas where extended reach is needed
• Use with hand-held drills and drill presses that accept hex shanks

Key specifications

• Cutting diameter: 20 mm
• Overall length: 400 mm
• Shank type: 6-sided (hex) shank
• Shank thickness: 7.9 mm
• Flute style: spiral for chip removal
• Intended material: wood and similar soft materials

How to use

Secure the spiral drill in a compatible chuck or quick-change hex holder, ensuring the 6-mm hex shank is fully engaged and clamped. Align the bit with the marked drilling point, start at low speed to center the drill, then increase speed as the flute engages the material. Apply steady, moderate pressure—avoid excessive force that could cause bending of the long shaft. Periodically withdraw the bit during deep drilling to clear chips and reduce friction. For precise positioning, use a pilot mark or punch before drilling.

Usage recommendations

Use appropriate drill speeds for wood, keep the bit straight to prevent wobble, and clear chips regularly to extend bit life. Wear eye protection and follow general workshop safety practices when using long-reach drill bits.