Special grade solid carbide Bits feature unique grinding and multi spiral flute design. Suitable for 'roughing' Cuts in hard and abrasive composite materials. Special grade carbide for maximum durability. Down-cut for better clamping when machining small work pieces and improved finish on the top of the board. For use on routers and CNC machines, #46133, diameter (D) 1/4, cutting Height (B) 1, shank (D) 1/4, overall length (L) 2-9/16, solid carbide end mill point roughing spiral 1/4 dia x 1 x 1/4 shank for composite materials