It is an object of the present invention to provide a rotary cutting tool that can divide chips at an appropriate size, suppress the incidence of edge chipping and damage attributed to chips to the cutting tool and a workpiece, extend the tool service life with regard to the machining of hard, brittle materials, and improve machining efficiency. The rotary cutting tool includes a hard coat film 3 coated onto a tip end section of a tool body 1 having a chip discharge groove 2. A rake face 6 is concavely provided in a cutting edge-side chip discharge groove formation surface 4 constituting the chip discharge groove 2 of the tool body 1, from a cutting edge 5 and along the cutting edge 5.

A magnetic base for an electric machine tool, in particular for a magnetic core drilling machine. A body that is accommodated in a receiving space. At least one first magnet coil constituting an electromagnet, a coil winding of the at least one first magnet coil being wound on a bobbin and a magnetic force of which is switchable between a maximum resultant holding force and a minimum resultant holding force. The coil winding of the magnet coil has two end sections that are each connected to a connecting cable that serves to make electrical contact between the magnetic coil and the electric machine tool. The body has a first side adapted to be coupled to the electric machine tool and has an opposite second side adapted to be placed on a workpiece that is to be processed. End sections of the coil winding are connected to the connecting cables.

A jig tool set for constructing a full thread bolt, and a method of constructing a full thread bolt using the jig tool set. The jig tool set includes a drill bit, a connecting rod, an anchor bolt set, a full thread bolt, and a drill gun. The drill bit includes a drilling part to secure a hole by drilling a ceiling slab made of concrete at one end. The anchor bolt set is fixed to the hole formed in the ceiling slab through the drill bit and configured to form the full thread bolt in the ceiling slab. The connecting rod has a certain length so that, as the drill bit and the anchor bolt set are sequentially seated at one end thereof. A drill gun is formed at the other end of the connecting rod and configured to provide a rotational force and a hitting force.

A glass article (100) includes a core layer (102) formed from a core glass composition with a core coefficient of thermal expansion (CTE) and first (104) and second (106) cladding layers fused to first and second major surfaces of the core layer (102) and formed from a clad glass composition comprising a clad CTE. An aperture (120) extends through each of the core layer (102), the first cladding layer (104), and the second cladding layer (106). The clad CTE is less than the core CTE such that each of the first (104) and second (106) cladding layers is under a compressive stress and the core layer (102) is under a tensile stress. A flexural strength of the glass article (100) can be at least about 75 MPa. A peak load sustainable by the glass article (100) in a modified ring-on-ring test can be at most 96.5% less than a peak load sustainable by a reference glass article in the modified ring-on-ring test.

A cutting tool with a plurality of cutting elements connected to a support structure wherein a portion of the support structure is configured to flex or bend based on the rotational frequency of the cutting tool. The rotational frequency of the cutting tool is a product of the design and composition of the tool.

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.

A drill bit for chiselling rock includes an impact face at an insertion end of the drill bit, a hollow shank, where a delivery passage is defined within the hollow shank, and a drill head, where the drill head has a cutting edge, an intake opening, and an intake passage and where the intake passage connects the intake opening to the delivery passage. A first portion of the intake passage which adjoins the intake opening has a first inclination with respect to a drill bit axis, a second portion of the intake passage which adjoins the hollow shank has a second inclination with respect to the drill bit axis, and the second inclination is greater than the first inclination.

[Problem] To protect a leading end part of a drill having a coolant hole which is adapted for drilling a thin diameter or very thin diameter hole in a workpiece.

[Solution] A coolant hole 33 is formed in a shank 3 and a shaft body 7 so as to extend through from a rear end surface 31 of the shank 3 to a leading end surface 15 of the shaft body 7 along an axis thereof. A leading end part of the coolant hole 33 is branched into a pair of discharge holes 35, at a position slightly toward a base end relative to the leading end surface 15 of the shaft body 13. The discharge holes 35 extend in the opposite directions, perpendicular to the coolant hole 33, respectively, and open at opposite side surfaces 37, 37 to define discharge ports 39, 39. A leading end opening 41 of the coolant hole 33 is closed by a bottom face 17 of the drill part 9.