Abstract: A drill bit includes a shank defining a longitudinal axis and a cutting edge extending radially outward relative to the longitudinal axis. The cutting edge is configured to remove material from a workpiece along a cutting path during a cutting operation. The drill bit further includes a plurality of scoring elements positioned within the cutting path and configured to contact the workpiece before the cutting edge during the cutting operation.

Abstract: A device for measuring the field of vision for a person wearing a mask indes a mask support to which the mask can be clamped and which is horizontally movable for aligning one of the subject's eyes with a horizontal axis. A scale support carries a scale member that is rotatably mounted around the horizontal axis and which carries a slidable indicator which can be slid to angles from 0.degree. to 90.degree. with respect to the axis. A mirror is attached to the scale support and lies on the axis for aiding and aligning on the subject's eye with the axis. A pointer is connected to a far end of the scale member and is used to locate the vertical perpendicular position of the subject's eye on the horizontal axis. The scale member is rotatably mounted on the scale support about the horizontal axis and the scale support is movable vertically to bring the horizontal axis into alignment with the subject's eye.