US Patent 7210881 Sleeved stop for a drill bit

A stop for use with an electric drill bit, the stop having at least one threaded sleeve for positioning the stop relative to a surface into which the drill bit will extend. The stop may have both an inner and an outer sleeve. The sleeves are mounted coaxially, one inside the other about the drill bit. One of the sleeves, preferably the inner sleeve, provides coarse adjustment of the position of the shoulder relative to the tip of the bit, while the other, preferably the outer sleeve, provides fine adjustment of the position of the shoulder relative to the top of the bit.