A coated tool of the present disclosure is provided with a base member and a coating layer located on a surface of the base member. The coating layer includes a TiCNO layer and an Al.sub.2O.sub.3 layer. The Al.sub.2O.sub.3 layer is located in contact with the TiCNO layer at a position farther from the base member than the TiCNO layer is. The TiCNO layer includes a composite protrusion including a first protrusion that projects toward the Al.sub.2O.sub.3 layer, a second protrusion that projects from the first protrusion in a direction intersecting a direction in which the first protrusion projects, and a third protrusion that projects from the second protrusion in a direction intersecting the direction in which the second protrusion projects.

A coated tool of the present disclosure is provided with a base member and a coating layer located on a surface of the base member. The coating layer includes a TiCNO layer and an Al.sub.2O.sub.3 layer. The Al.sub.2O.sub.3 layer is located in contact with the TiCNO layer at a position farther from the base member than the TiCNO layer is. The TiCNO layer includes a composite protrusion including a first protrusion that projects toward the Al.sub.2O.sub.3 layer, a second protrusion that projects from the first protrusion in a direction intersecting a direction in which the first protrusion projects, and a third protrusion that projects from the second protrusion in a direction intersecting the direction in which the second protrusion projects.

A cutting insert in a non-limiting aspect of the present disclosure may include an upper surface, a lower surface, a lateral surface and a cutting edge. The upper surface may include a first corner and a first side. The upper surface may further include a rake surface, a bottom surface and a raised surface. The bottom surface may include a first bottom surface and a second bottom surface. The first bottom surface may be located on a bisector of the first corner. The second bottom surface may be located inwardly of the first side. The first bottom surface may be an inclined surface located closer to the lower surface as going away from the first corner. The second bottom surface may be an inclined surface located further away from the lower surface as going away from the first side.

A cutting insert in a non-limiting aspect of the present disclosure may include an upper surface, a lower surface, a lateral surface and a cutting edge. The upper surface may include a first corner and a first side. The upper surface may further include a rake surface, a bottom surface and a raised surface. The bottom surface may include a first bottom surface and a second bottom surface. The first bottom surface may be located on a bisector of the first corner. The second bottom surface may be located inwardly of the first side. The first bottom surface may be an inclined surface located closer to the lower surface as going away from the first corner. The second bottom surface may be an inclined surface located further away from the lower surface as going away from the first side.

A cutting tool includes: a substrate; a hard layer provided on the substrate; and a titanium carbonitride layer provided on the hard layer, wherein a thickness of the titanium carbonitride layer is more than or equal to 2 μm, a hardness of the titanium carbonitride layer at a room temperature is more than or equal to 35 GPa, and a Young's modulus of the titanium carbonitride layer at the room temperature is less than or equal to 650 GPa.

Provided is a coated cutting tool having a base material side single layer portion and a laminated portion provided as a hard coating in order from a base material side. The base material side single layer portion is formed of a nitride-based hard coating in which a proportion of Al is highest among metal (including metalloid) elements, a sum of Al and Cr in a content ratio (atomic ratio) is 0.9 or more, and at least B is contained. In the laminated portion, a nitride-based a layer in which a proportion of Ti is highest among metal (including metalloid) elements and at least B is contained, and a nitride-based b layer in which a proportion of Al is highest among metal (including metalloid) elements and at least Cr and B are contained are alternately laminated.

A method for deburring an internally toothed workpiece includes providing a workpiece and a deburring tool. The workpiece has an inner toothing produced by hob peeling, with first and second tooth flanks. The deburring tool has a first cutting plate and a second cutting plate, diametrically opposed to the first cutting plate. The method includes rotating the workpiece in a first rotating direction and deburring the first tooth flanks with the first cutting plate while the deburring tool is not rotating. The method also includes shifting the deburring tool relative to the workpiece such that the first cutting plate and the second cutting plate do not contact the workpiece, rotating the workpiece in a second rotating direction, opposite the first rotating direction, further shifting the deburring tool relative to the workpiece, and deburring the second tooth flanks with the second cutting plate while the deburring tool is not rotating.

A method for deburring an internally toothed workpiece includes providing a workpiece and a deburring tool. The workpiece has an inner toothing produced by hob peeling, with first and second tooth flanks. The deburring tool has a first cutting plate and a second cutting plate, diametrically opposed to the first cutting plate. The method includes rotating the workpiece in a first rotating direction and deburring the first tooth flanks with the first cutting plate while the deburring tool is not rotating. The method also includes shifting the deburring tool relative to the workpiece such that the first cutting plate and the second cutting plate do not contact the workpiece, rotating the workpiece in a second rotating direction, opposite the first rotating direction, further shifting the deburring tool relative to the workpiece, and deburring the second tooth flanks with the second cutting plate while the deburring tool is not rotating.

A polycrystalline cubic boron nitride includes a cubic boron nitride particle group. The ratio of a second length to a first length is 0.99 or less. Here, each of the first length and the second length is a value measured on a surface of the polycrystalline cubic boron nitride with an indentation formed by a Knoop hardness test under conditions specified in ISO4545-1 and ISO4545-4. The second length represents the length of the longer diagonal of the indentation. The first length represents the sum of the second length and the length of the streaky indentation.

A board drilling apparatus, drill bit, and method for board drilling apparatus to drill a board. The board drilling apparatus (4) is configured to drill a board comprising at least a target conductive layer (13), an insulation layer, and a hole (3) covered with conductive material through at least part of the board in thickness, to remove at least part of the conductive material, the board drilling apparatus (4) comprising a drill bit (41) and a controller (43): the drill bit (41) comprising an insulation part (412) at least in center of end of the drill bit (41) and a conductive part (411) at least on edge of the end of the drill bit (41), arranged to enable only the insulation part (412) to be in touch with the conductive material of the hole (3) when the board drilling apparatus (4) is drilling the board, and arranged to enable the conductive part to get in touch with the target conductive layer (13) once the conductive material on the way to the target conductive layer (13) has just been removed; and the controller (43) configured to stop drilling when receiving an electrical signal occurred in response to the drill bit touching the target conductive layer of the board.