A drill having a shank formed with helical or straight flutes for discharging chips therethrough and a pair of cutting edges formed at one end of the shank and extending continuously from the center of rotation of the drill to the periphery thereof. Each of the flutes is defined by a wall which is positioned rearward with respect to the direction of rotation of the drill and against which a flat plate portion of the chip formed by the portion of the cutting edge on the peripheral side is to be p...

A drill capable of drilling a deep hole while keeping high chip discharging ability and having a helical flute whose width and helix angle will not change even after the cutting edges have been regenerated by regrinding. The drill has a tip portion formed with a helical flute having a constant width and helix angle, a rear portion formed with a helical flute which are greater in width and smaller in helix angle than the helical flute formed in the tip portion, and a middle portion provided betwe...

A drill for forming bores in constructional components, and including a sleeve-shaped stem (2; 12; 22; 32; 42; 52) having an axially-extending through-bore (3; 13; 23; 33; 43; 53) which opens into mouth openings (7; 10; 14; 24; 34; 44; 54) formed in opposite end sections of the stem (2; 12; 2; 32; 42; 52); a shank (5) provided at a rear end of the stem, and a drilling head (8; 15; 25; 35; 45; 55) formed of a hard material and secured in at least one slot (19; 29; 49; 59) formed in a free front e...

A chip discharge flute 22 is formed on the side surface of a drill main body 21 to be rotated about an axial line from the tip to the base end of the drill main body 21 and a cutting edge 25 is formed along the intersecting ridge where the wall surface 23 of the chip discharge flute 22 facing to the drill rotational direction thereof intersects with the tip flank 24 of the main body 21. A first cutting edge 26 is formed to a core thick portion at the tip of the drill main body 21 and linearly ex...

A drill comprising a holding section, a prismal section receivable by the holding section, and a top-truncated, pyramidal section which is integral with the prismal section, with the prismal section having side faces and side ridges defined by the adjoining two side faces, the top-truncated, pyramidal section having end faces which taper and coverage on the axis of rotation of the drill, end ridges which are defined by meeting of the adjoining two end faces, and a truncated surface extending acr...

A drill including a bit having an extension received in and axially extending groove formed in the end face of the drill base body, a side cutting edge projecting beyond the base body circumference, and two active end cutting edges projecting beyond the end face of the base body, with the drill further including clamping elements for securing the bit extension in the base body groove with a possibility of radial adjustment.

A drill having a drill head with a drill shank extending between the drill head and a plug-in end lying opposite the drill head, said drill shank having a conveying helix formed by at least two helical flutes and webs located between the flutes. The flutes comprise the same clear cross section at least in the region of the end of the drill shank adjacent the drill head and are arranged at an angle a in a range of 130.degree. through 170.degree. relative to one another.

The present invention relates to a drill comprising a shaft with chip-conveying flutes and a drill head with two or more cutting elements. Each of the cutting elements comprises a cutting edge which is delimited between a chip-breaking surface and a relief surface and which, at least in the proximity of the geometrical center or rotational axis of the drill, comprises a curved portion. The cutting edge of the individual cutting elements is located with its curved portion in such a way that a tan...

An improved drill for creating oval openings in the jawbone for a tooth to be implanted therein. The drill includes movable cutters that cut an oval shape that matches the cross section of the oval implant by being rotatably driven and performing very fine cuts with movable cutters on an initial pilot hole in the bone.

A drill for stack drilling comprises a drill body, a central cutting insert, and a peripheral cutting insert. The inserts have active cutting edges arranged such that the drill successively cuts radially outwardly from the center of the drill in order to avoid the formation of break-out slugs. The active cutting edge of the central insert has three cutting edge portions forming obtuse angles with one another. The radially innermost one of those cutting edge portions is shorter than each of the o...