Irwin 4X Blue Groove Flat Wood Drill Bit

The 40mm IRWIN® Blue Groove 4X Flat Bit is the largest size in the range, designed for the most demanding heavy-duty drilling tasks in timber. This substantial diameter is ideal for major waste pipe installations, large cable entry points, and significant structural construction work where maximum clearance is required. Featuring the patented groove point and cutting edge technology, this 40mm bit cuts through timber cleanly and efficiently without scraping, ensuring professional results even at this maximum diameter. The advanced design delivers speeds up to 4 times faster than standard flat bits, dramatically improving productivity on these substantial drilling operations. The parabolic scoop provides superior chip removal and maintains excellent control, particularly important when working with this largest size. With an increased relief angle of 17° for enhanced cutting performance and a robust 152mm shank manufactured 10% larger in diameter, this bit is built for the most demanding professional applications. The strengthened construction resists bending and maintains accuracy even under sustained intensive use, making it the ultimate choice for major trade projects.