Drill Bit Irwin Spiral tree gr. 14 x 335/400 x 9.2 mm – for wood, spiral auger

Irwin spiral tree auger drill bit 14 x 335/400 x 9.2 mm is designed for drilling deep, clean holes in wood. With a 14 mm cutting diameter and options for overall length of 335 mm or 400 mm, this auger bit combines a sharp lead screw and spiral flute geometry to pull the bit into the workpiece and eject chips efficiently. The 9.2 mm shank/profile fits hand braces and many power drills with compatible chucks, making the bit suitable for both manual and powered woodworking tasks. Intended for carpentry, joinery and general timber work, the bit produces precise through- and blind-holes in soft and hardwoods when used at appropriate speeds.

Advantages

The spiral auger design ensures rapid chip removal and reduced clogging during deep drilling, while the lead screw tip provides self-feeding and accurate centring. Available in two overall lengths, the bit allows access to deeper drilling points without sacrificing rigidity. The 9.2 mm shank gives good compatibility with a wide range of drill chucks and hand braces, and the hardened cutting edges retain sharpness for consistent performance in repeated woodworking operations.

Suitable for

• Drilling deep holes in construction timber and beams
• Carpentry and joinery—creating holes for dowels, bolts and pegs
• Furniture making and repair where long-reach holes are needed
• General woodworking tasks in softwoods and many hardwoods

Key specifications

• Cutting diameter: 14 mm
• Overall length options: 335 mm or 400 mm
• Shank/profile diameter: 9.2 mm
• Spiral (auger) flute geometry for efficient chip evacuation
• Lead screw tip for self-feeding and accurate centring

How to use

Secure the drill bit in a compatible chuck or hand brace, ensuring the 9.2 mm shank is held firmly. Position the lead screw tip on the intended drilling point and start drilling at a moderate speed suitable for the wood species; allow the lead screw to draw the bit into the workpiece without applying excessive forward force. Withdraw the bit periodically for long holes to clear chips if necessary, or rely on the spiral flute to eject chips continuously. For blind holes, monitor depth and back out the bit occasionally to prevent jamming and overheating.

Usage recommendations

Use cutting oil or a light lubricant only when drilling through resinous woods to reduce heat and improve chip flow. Match drilling speed to the wood type—lower speeds for hardwoods and higher speeds for softwoods—and always wear appropriate eye and hand protection when operating power tools or hand braces.