Spiral-flute bits combine a shearing action in cutting with an augering action in chip clearance. The shearing action yields an especially clean accurate cut while the augering action clears chips from the cut. The ‘Up-Cut’ shears from the bottom up pulling chips from the bottom up thus allowing deeper penetration with less stress on the tool. An excellent choice for mortising.

A downcut bit is the perfect choice for cuts where having a clean top surface. The down cut action of the bit cuts from the surface down ensuring that you have a perfectly clean top edge reducing any fraying or chipout that would be left if you were using an upcut bit for the same cut.