This carbon steel forstner bit gives you a clean, flat bottomed hole from any angle. It is excellent for drilling all thicknesses of wood including thin materials and veneers without breakthrough and splintering. It is guided from the outer rim and will not move off center. This 3/8" bit has a shank size of 3/8". The maximum recommended RPM's for this forstner bit is 1600 (hardwoods) and 2400 (softwoods).