초록 ▼

A self-centering indexable drill having cutting inserts disposed such that cutting forces on the inboard and outboard flutes of the drill body are substantially equal while boring a hole, thereby keeping the drill body substantially centered. The drill includes a drill body and a plurality of cuttin

A self-centering indexable drill having cutting inserts disposed such that cutting forces on the inboard and outboard flutes of the drill body are substantially equal while boring a hole, thereby keeping the drill body substantially centered. The drill includes a drill body and a plurality of cutting inserts. The drill body includes a shank portion configured to be received by the spindle of a machine using the drill, a collar, and a fluted portion. The fluted portion of the drill body defines an inboard flute and an outboard flute. At least one cutting insert is releasably secured to each of the inboard and outboard flutes, with an equal number of cutting inserts carried by each. An insert pocket is defined by the drill for closely receiving each cutting insert such that the leading face of the cutting insert is substantially flush with the face of the flute. The cutting inserts are spaced on the inboard and outboard flutes such that as the drill bores a workpiece, the material removed by the cutting inserts on the inboard flute is equal to that removed by the cutting inserts on the outboard flute. The exposed cutting edge of the innermost inboard cutting insert is disposed at a first angle with respect to a line normal to the axis of rotation. Each remaining cutting insert carried by the inboard flute, and each cutting insert carried by the outboard flute is disposed at a second angle with respect to a line normal to the axis of rotation. A drill guide may be provided for assisting in preventing the drill from drifting off-center, especially when the exit surface of the workpiece is not parallel to the entrance surface of the workpiece.

대표청구항 ▼

[ We claim:] [1.] A self-centering indexable drill for drilling a hole in a workpiece, said self-centering indexable drill comprising:a drill body having a cylindrical configuration defining an axis of rotation and further defining at least a shank portion and a fluted portion, said fluted portion i

[ We claim:] [1.] A self-centering indexable drill for drilling a hole in a workpiece, said self-centering indexable drill comprising:a drill body having a cylindrical configuration defining an axis of rotation and further defining at least a shank portion and a fluted portion, said fluted portion including an inboard flute and an outboard flute;a first cutting insert carried by said drill body on said inboard flute, said first cutting insert defining a cutting edge having a first end and a second end, said first cutting insert being disposed on said inboard flute such that said cutting edge intersects said axis of rotation between said first and second ends of said cutting edge proximate said first end thereof, said first cutting insert being disposed at a first angle with respect to said axis of rotation and defining a first cutting area for removal of material from the workpiece, said first angle being within the range of four to seven degrees; anda second cutting insert carried by said drill body on said outboard flute, said second cutting insert defining a cutting edge having a first end and a second end, said second cutting insert being disposed on said outboard flute such that said cutting edge second end extends beyond an outside diameter of said drill body, said second cutting insert being disposed at a second angle with respect to said axis of rotation, said second cutting insert defining a second cutting area substantially equal to said first cutting area of said first cutting insert, said second angle being within the range of fourteen to nineteen degrees.