A machining tool assembly is provided for machining a blank to form a firearm lower receiver. The assembly includes a pair of side plates positionable on opposed sides of the blank to capture the blank therebetween. A template plate having a template aperture is adapted to be removeably attachable to the side plates. The template aperture is aligned with a top surface of the blank and is adapted for machining a cavity within the blank having a peripheral contour complimentary to a peripheral contour of the template aperture. A centering mechanism is adapted to be removeably attachable to the template plate, with the centering mechanism including an opening aligned with a corresponding void formed on the blank to align the blank with the template plate.

A drill head for deep-hole drilling includes cutting blade tips brazed to cutting chip discharge ports opened on a head distal end surface, guide pads mounted on a plurality of positions of the circumferential surface at the head distal end side, and a hollow inside portion made into a cutting chip discharge passage communicating with the cutting chip discharge ports. A guide pad portion having an arc surf ace that slide-contacts with the inner circumference of a cutting hole is formed on the outer end surface of the circumferential portion cutting blade tip.

A drill head for deep-hole drilling includes cutting blade tips brazed to cutting chip discharge ports opened on a head distal end surface, guide pads mounted on a plurality of positions of the circumferential surface at the head distal end side, and a hollow inside portion made into a cutting chip discharge passage communicating with the cutting chip discharge ports. A guide pad portion having an arc surface that slide-contacts with the inner circumference of a cutting hole is formed on the outer end surface of the circumferential portion cutting blade tip.

A device for assisting an operator of a boring instrument having a penetrating element for penetration a work surface that includes a retention member adapted to be connected to a rotating element of the boring instrument and adapted to receive a laser and a plurality of mirrors including a beam splitting alignment mirrors that directs a laser beam in a direction parallel with a penetrating element and perpendicular to a work surface, and a depth indication mirror that reflects a light beam at an angle of less than 90 degrees from said retaining member to a location on said work surface wherein the location of the beams from the alignment beams is maintained at a fixed radial position when the retention member perpendicularly moves towards a work surface and wherein the beam is rotated defines a circle.

The invention is directed to a drill system that better uses the power curve of modern machine tools. The drill system uses IC inserts to perform the major hole diameter cutting, and a central drilling system that cuts the remaining minor diameter portion of the hole, and is configured to see less cutting surface footage, due to its position from the rotating center of the tool. A connection between the drill head and a holder body secures the drill head in a manner to effectively absorb lateral drilling forces. The drill system allows for a large diameter deep hole that remains straight throughout to be drilled at higher speed and lighter feed rates thus offering a more productive tool that takes advantage of the power curves and lower thrust capabilities of modern machine tools.