Abstract: A masonry drill bit having an improved insert geometry, insert orientation, and interface clearance for providing improved drill speed and penetration rate. The drill bit is adapted for use in drilling masonry or other hard, brittle material. The drill bit has an axially elongated body with a leading front end portion and a rear end portion. The rear end portion is adapted to be held by a tool holder. The body has at least one spiral groove cast in its exterior surface substantially along its length. The insert is embedded in the leading end of the body, extending generally diametrically across the leading end of the body, and centered about a latitudinal plane of the insert. The geometric design of the insert, the orientation of the insert relative to the drill bit, and the interface clearance between the insert and the grooves, reduces friction and heat; resists wear, fractures, and abrasive actions of the chips; increases design life of the elements; and enhances debris elimination.

Abstract: A double-ended drill bit having opposed cutting ends of different structural configurations is provided in combination with a sleeve or holder to be received within a drill chuck. The sleeve is provided with a cylindrical body having a top end with a pair of helically-shaped longitudinally extending members in spaced mating relation attached thereto. One cutting end of a drill bit is received within the cylindrical body and the spaced helically-shaped members.

Abstract: A circular saw blade with improved stability, the blade having a plurality of radial expansion slots, preferably having a "J"-shape. The blades may also have a plurality of arced body slots and may be coated with a "TEFLON" paint mixture.