Made exactly to our specifications, these bits took over a year to develop and refine. The great advantage of high-speed steel (HSS) bits is that heat build-up will not soften them, as will happen with carbon steel.
The rim on these forstners is proud of the chippers by only 0.005" to 0.010", reducing rim heat. They have slightly sloped chipping bevels so that bits ride a shallow cone of wood to keep them boring straight. Center brads can then be shorter, increasing bit versatility in thin material. As a last touch, bits have been finished with extra-fine grinding wheels to reduce friction.
Shank diameter is 3/8".