The IRWIN® Blue Groove 4X Flat Bits have a patented groove point and cutting edge, designed to cut and not scrape the timber. They are 4 times faster than standard flat bits. The parabolic scoop optimises control and removal of wood chips.

Increased relief angle from 12° to 17°. The shank is 152mm in length and 10% larger in diameter for added durability.

The Irwin IRW10502811 Blue Groove 4x flat bit has the following specific dimension:
Diameter: 18mm