1-5/8" (Dia.) Forstner Bit From the Manufacturer Precision Shear Forstner Bits feature a double-ground, razor-sharp serrated edge that slices throughout the rotation of the bit for less splintering and chipping, producingflawless flat-bottom holes. This unique geomtric design has multiple cutting edges that produce greater shearing action, allowing for faster rotational speeds and more efficient cutting. Competitive forstner bit designs produce small chips and dust that collect in the cutting area, increasing friction and heat, thus causing the bit to dull quickly. Those designs also create holes with rough edges that require sanding. In addition to serrated edges, Precision Shear Forstner Bits include a hardened steel body for longer life and sharper edge, an ultra sharp spur to ensure accurate holes and less "walking", and steep angled cutting edges to produce holes that are smooth and flat.