A power tool including a housing and a motor mounted in the housing having a drive shaft. A transmission is mounted in the housing having an input shaft operatively coupled to the drive shaft of the motor and an output shaft operatively coupled to a tool holder. The transmission includes at least a first gear and a second gear configured to transmit torque from the motor to the tool holder. A first part of the transmission is mounted within a first grease chamber and a second part of the transmission is mounted within a second grease chamber.

One example of the present disclosure relates to a coupon. The coupon includes a first surface with a first circular channel and a second surface opposite and parallel to the first surface. The second surface is spaced a distance D0 from the first surface and includes a second circular channel concentric with the first circular channel. The coupon also includes a toroidal portion between the first circular channel and the second circular channel. The toroidal portion includes a rectangular sectional portion.

A medical drill bit comprises an accommodating slot disposed concavely on a main body of the medical drill bit, a separate board disposed in the accommodating slot to separate the accommodating slot into a first slot and a second slot, and a lid engaging with the separate board and covering the accommodating slot. The lid and the separate board do not rotate with the main body when the main body in rotation. The accommodating uses to fill with cooling liquid which able to be pumped out from the accommodating slot, and fresh cooling liquid is able to inject into the accommodating slot for cooling the drill bit in rotation.

A cutting tool replacement member including: a lower surface which serves as a seating surface; an upper surface opposed to the lower surface; and a side surface connected to the upper surface and the lower surface. In a top view, the upper surface includes, in an intersection between the upper surface and the side surface, a reference side edge and an inclined side edge inclined relative to the reference side edge. The side surface includes a first side surface part connected to the reference side edge of the upper surface, and a second side surface part connected to the inclined side edge of the upper surface. At least one of the first side surface part and the second side surface part is provided with an overhanging part that, in a top view, protrudes outwardly with respect to the reference side edge or the inclined side edge.

A drive shaft for a machine tool is connectable to a drilling tool. The drive shaft contains a cavity extending substantially over the entire length of the drive shaft and along the axis of rotation where the cavity contains an inflow opening through which water can be fed along the drive shaft into the drilling tool. An insert device is provided in the cavity, through which, to cool the drive shaft, the water is guided first in a first direction and then in a second direction where the insert device contains a first curved guide element and a second curved guide element for separating the water which is guided in the first direction from the water which is guided in the second direction. The cross-sectional area of the first curved guide element is designed point-symmetrically about a center longitudinal axis to the cross-sectional area of the second curved guide element.

Provided is a method of drilling a hole in a drilling object by using a hole drilling device 1 including: a drill bit 3 including a cutting edge on a distal end thereof; and an electric drill 2, which rotates the drill bit 3, the method including a cutting step of rotating the drill bit 3 to drill a hole in the drilling object in a state where a water-soluble gel coolant is applied to the distal end of the drill bit 3.

One example of the present disclosure relates to a coupon. The coupon includes a first surface with a first circular channel and a second surface opposite and parallel to the first surface. The second surface is spaced a distance D0 from the first surface and includes a second circular channel concentric with the first circular channel. The coupon also includes a toroidal portion between the first circular channel and the second circular channel. The toroidal portion includes a rectangular sectional portion.

A suctioning cover for a core drill bit of a core drilling device is attachable to a rear side of the core drill bit in order that material for suctioning can be suctioned out of an interior of the core drill bit. The suctioning cover has a valve for setting a pressure in the interior of the core drill bit. The pressure regulating valve allows automatic setting of the pressure in the interior of the core drill bit, such that work can be performed using the core drill bit in an optimum pressure range. Material for suctioning can thus be suctioned out of the interior of the core drill bit particularly effectively. The suctioning cover can be used in particular when performing dry drilling using the core drill bit. A method of operating the suctioning cover, wherein the valve for setting the pressure can be used to set a pressure in the interior of the core drill bit or in a cavity of the suctioning cover.

A bolt on drive assembly for a core drill which utilizes an improved high strength spoked reinforcer mounted beneath a disc. The disc and high strength spoke reinforcer are removably mounted on the tube by bolt fasteners. A drive connection is removably mounted and centrally located on a outer disc of the pair of discs. The drive connection is adapted to connect with a drive shaft to cause rotation of the tube. The system can also include a split in the disc when the high strength spoked reinforcer is not welded thereto thereby providing a means of water control. The high strength spoked reinforcer can be a separate piece that is bolted to the disc or can be integrally formed as one piece therewith. An adapter is provided that allows for standard drilling that fits into a recess in the center hub and is removable to expose the recess for attachment to a specialized drill motor, such as an A-flange.

A body of a cutting tool may include a shank and a tip having spaced-apart, helical flutes. Each spaced-apart, helical flute may include a helical cutting edge extending from a tip bottom, adjacent a shank top, to a tip top. The tip may include chip gash paths. Each chip gash path may be recessed between two of the spaced-apart, helical flutes, and extend from the tip bottom to a tip top portion. The body may include helical coolant channels extending from entrances at a shank bottom, to within a shank interior, to within a tip interior, to tip coolant orifice exits. The coolant orifice exits may be disposed in the spaced-apart, helical flutes adjacent the chip gash paths or disposed in relief surfaces extending from the tip top downward to the chip gash paths. The coolant orifice exits may be spaced-apart from the tip top.