A hole drilling device for forming an expanded-diameter hole portion at an inner bottom part of a mounting hole includes: a shaft including a contact surface and a tapered surface, and a cutter including a stopper provided on a side surface of the cutter, the stopper coming into contact with a surface of a drilling object. The cutter is movable between a first position and a second position. When the cutter is in the first position, the contact surface is in contact with the inner bottom part of the mounting hole, and the stopper is away from the surface of the drilling object. When the cutter is in the second position, the cutter has been pushed in forward from the first position, the cutting bit has protruded laterally from the tapered surface, and the stopper is in contact with the surface of the drilling object.

A hole drilling device for forming an expanded-diameter hole portion at an inner bottom part of a mounting hole includes: a shaft including a contact surface and a tapered surface, and a cutter including a stopper provided on a side surface of the cutter, the stopper coming into contact with a surface of a drilling object. The cutter is movable between a first position and a second position. When the cutter is in the first position, the contact surface is in contact with the inner bottom part of the mounting hole, and the stopper is away from the surface of the drilling object. When the cutter is in the second position, the cutter has been pushed in forward from the first position, the cutting bit has protruded laterally from the tapered surface, and the stopper is in contact with the surface of the drilling object.

A core drill bit can include a first region and a second region. The first region can include abrasive particles in a first bond matrix, and the second region can include abrasive particles in a second bond matrix. The first region is connected to the second region. A composition of the first bond matrix can be different from a composition of the second matrix. In a particular embodiment, the first bond matric can include a Co-containing material.

A method employing an apparatus in conjunction with a hammer-drill to penetrate composite metal and non-metal structure or structures including, for example, thick metal or rebar encountered during concrete, rock or masonry boring operations without requiring a change in drill equipment.

An automatic machine for drilling and milling substantially flat glass sheets shape, comprising includes a machine body; an input conveyor provided with a motorized roller conveyor or roller belt that conveys the glass sheet by its lower edge; an input conveyance surface provided with idle gliding wheels; an output conveyor provided with a motorized roller conveyor or motorized belt that conveys the glass sheet by means of its lower edge; and an output conveyance surface provided with idle gliding wheels. The machine further includes at least one carriage provided with synchronous horizontal motion along the longitudinal axis X2; and at least one pair of working heads provided independently with a synchronous vertical motion for adjustment and feeding along the axes Y1 and Y2, wherein, each head bears a tool provided with rotary motion (cutting) and feeding motion along the axes Z1 and Z2.

An automatic machine for drilling and milling substantially flat glass sheets shape, comprising includes a machine body; an input conveyor provided with a motorized roller conveyor or roller belt that conveys the glass sheet by its lower edge; an input conveyance surface provided with idle gliding wheels; an output conveyor provided with a motorized roller conveyor or motorized belt that conveys the glass sheet by means of its lower edge; and an output conveyance surface provided with idle gliding wheels. The machine further includes at least one carriage provided with synchronous horizontal motion along the longitudinal axis X2; and at least one pair of working heads provided independently with a synchronous vertical motion for adjustment and feeding along the axes Y1 and Y2, wherein, each head bears a tool provided with rotary motion (cutting) and feeding motion along the axes Z1 and Z2.

A drilling tool, in particular a rock drilling tool, for a portable machine tool, includes an axis of rotation, at least one spiral path, and at least one wear surface transition. The at least one spiral path is coiled about the axis of rotation along the axis of rotation and includes at least one wear surface having at least one bandwidth. There is a change in the at least one bandwidth of the at least one wear surface at a position of the at least one wear surface transition.

A quick-changing brazed drill includes a drill body and a quick-changing joint. The drill body is connected to the quick-changing joint detachably, and a vent hole is provided at a connection point between the drill body and the quick-changing joint. The drill body has a cylindrical structure, an interior of a front end of the drill body is hollow, and an outer side of the front end of the drill body is provided with 2-6 grooves. The quick-changing joint includes a transition block and a rear cover; a rear end of the transition block is connected to the rear cover by an external thread; a snap-fit area is provided between the transition block and the rear cover; a middle portion of the transition block is provided with a first threaded hole and is connected to a rear end of the drill body.

A quick-changing brazed drill includes a drill body and a quick-changing joint. The drill body is connected to the quick-changing joint detachably, and a vent hole is provided at a connection point between the drill body and the quick-changing joint. The drill body has a cylindrical structure, an interior of a front end of the drill body is hollow, and an outer side of the front end of the drill body is provided with 2-6 grooves. The quick-changing joint includes a transition block and a rear cover; a rear end of the transition block is connected to the rear cover by an external thread; a snap-fit area is provided between the transition block and the rear cover; a middle portion of the transition block is provided with a first threaded hole and is connected to a rear end of the drill body.

To provide a method for forming an anchor hole and a diameter expansion device by which a centrifugal force can be appropriately adjusted when a cutting-blade portion is moved in a radial direction by the centrifugal force to grind a diameter expansion portion. In a method for forming an anchor hole for a post-installed anchor in which a diameter expansion drill bit is inserted and rotated in a prepared-hole portion bored in a concrete fixing body and a cutting-blade portion of the diameter expansion drill bit is moved in a radial direction by a centrifugal force to grind a part of the prepared-hole portion to form a diameter expansion portion, the minimum value of the centrifugal force applied to grind the diameter expansion portion is 0.75 N and preferably 1.1 N.