Abstract: A step drill and a manufacturing method for a step drill in which cutting performance of a cutting edge of a step portion can be enhanced are provided. A groove includes a first ground portion forming an area embracing a second cutting edge of the step portion and a second ground portion forming an area on the heel side of the step portion relative to the first ground portion. Therefore, a convex blade part can be formed on a first cutting edge by performing grinding with the first ground portion and the second ground portion intersecting with each other. That is, it is possible to form the second cutting edge into a desired shape during grinding of the first ground portion. Therefore, cutting performance of the second cutting edge can be enhanced.

Abstract: A thread forming tap includes a screw thread formed into a male thread shape with margin portions disposed to project in radial direction and relief portions having a diameter smaller than the margin portions, the margin portions and relief portions alternatively arranged and, thread forming tap causes the margin portions of the screw thread to cut into a surface layer portion of a prepared hole formed in a work to plastically deform the surface layer portion to form a female thread, margin portions are formed into a ridge line shape with a width dimension of zero at least at a thread bottom of the screw thread, and margin portions are formed into a ridge line shape with a width dimension of zero in a range from a thread bottom of the screw thread to a position between the thread bottom and an effective diameter position of the screw thread.

Abstract: A formed rotary cutting tool includes a cutting edge defining a cutting edge diameter that is increased and reduced in a direction of an axis of the tool, so as to have at least one neck portion in which the cutting edge diameter is minimized. The cutting tool includes a roughing portion which is provided on a periphery thereof and which is constituted by a succession of protrusions and recesses arranged in the direction of the axis. The roughing portion includes (i) a fine roughing portion that is provided in at least one of the at least one neck portion, and (ii) another portion that is provided in a portion that is other than the at least one of the at least one neck portion. The fine roughing portion of the roughing portion is different in characteristics from the above-described another portion of the roughing portion.

Abstract: A variable lead end mill has a plurality of peripheral cutting edges with different helix angles, the variable lead end mill having a flute bottom diameter of a plurality of helix flutes making up rake faces of the plurality of the peripheral cutting edges, the flute bottom diameter increasing in an axial direction from a tool tip toward a shank.

Abstract: A thread forming tap has a full thread portion and a leading portion contiguous with the full thread portion and reducing in diameter toward its tip. The full thread and leading portions are provided with external thread on which lobes and recesses are alternately formed. When ? represents an angle around a tool center line toward a thread forming side, the shape of the lobe varies along a quadratic curve relative to angle ? so that relief amount increases toward inflection point angle ?. However, in a rough plastic deformation section where angle ? is greater than inflection point angle ? and exceeds the working region, the shape varies along an Archimedean curve with clearance angle ?1 so that the relief amount increases linearly relative to angle ?, and a margin section is substantially zero or within a range where angle ? is less than or equal to 1°.

Abstract: To provide a tool that can reduce the maximum value of cutting resistance when adjacent peripheral edges cut a workpiece simultaneously. A lead L of a spiral flute 21, a waveform pitch P, the number of edges N of peripheral edges 22, and a natural number m are set to satisfy L/N=m×P?P/N±P/2 or L/N=m×P+P/N±P/2, the waveforms of adjacent ones of the peripheral edges 22 at the positions where they contact a workpiece simultaneously are in an anti-phase relationship when the adjacent peripheral edges 22 cut the workpiece simultaneously. Therefore, there is an effect that the length of the cutting edges that contact the workpiece simultaneously is shortened to reduce the maximum value of cutting resistance.

Abstract: A machining head replaceable rotating tool having a fastening male screw and a fastening female screw disposed on respective shaft centers of one and the other of a machining head and a holder, the fastening male and female screws being threadably engaged with each other to concentrically and removably attach the machining head to a tip portion of the holder, the machining head and the holder being disposed with abutting surfaces abutted against each other in a fastened state when the fastening male and female screws are threadably engaged, the machining head replaceable rotating tool being integrally and rotationally driven via the holder in a tool rotation direction causing the fastening male and female screws to be fastened by a machining load to perform predetermined machining with the machining head, the abutment of the abutting surfaces preventing the fastening male and female screws from being further fastened by a machining load, the fastening male and female screws being saw-tooth buttress screws hav

Abstract: A throw-away rotating tool includes plural protrusions formed in a part of an outer peripheral wall of a projecting coupling portion. Since the twist angle and a twist direction of the protrusions are set in such a way that with relative rotation when coupling the projecting coupling portion and erected portions together, due to the reaction force received by the protrusions from inner peripheral walls, the projecting coupling portion is pulled to the rear and side of the erected portions and the projecting coupling portion is stably held between the erected portions. Since the number of portions that require stringent dimension control and high machining accuracy can be reduced, productivity can be improved.

Abstract: A hard film excellent in abrasion resistance and heat resistance includes: a first film consisting of AlaCrb(SiC)c?dN, where ? denotes one or more elements of groups IVa, Va, VIa (except Cr) of the periodic table, B, C, Si, and Y; a b, c, and d are atom ratios within ranges of 0.35?a?0.76, 0.12?b?0.43, 0.05?c?0.20, and 0?d?0.20, respectively; an atom ratio b/a of Cr to Al is within a range of 0.25?b/a?0.67; and a+b+c+d=1 is satisfied. The first film disposed on a top surface, the hard film having a total thickness Ttotal within a range of 0.5 ?m to 15 ?m with a thickness T1 of the first film or, if another film portion having the same film components as the first film is included, a thickness including the film thickness T1 and the another film portion accounting for 20% or more of the total thickness Ttotal.

Abstract: A bevel head replaceable rotary tool is provided. The rotary tool includes a coupling protrusion and a coupling recess, plural sets of serrations provided on an outer circumferential surface of the coupling protrusion and an inner wall surface of the coupling recess, circumferential abutting portions provided on the tool body and the bevel head, and axial tight-contact portions, provided on the tool body and the bevel head. The serrations of the coupling protrusion and the serrations of the coupling recess arranged such that curvatures of circumferential circular arcs of the serrations of the coupling protrusion are greater than those of the serrations of the coupling recess or the serrations of the coupling protrusion and the serrations of the coupling recess have circumferential circular arcs with centers deviated from each other.

Abstract: In a semi-finishing cutter, rectangular tips and square tips are disposed in a staggered pattern in an axial direction in second to fourth step portions, so a single cutting edge is formed by a pair of one of the rectangular tips and one of the square tips. It is therefore possible to effectively reduce a frequency of contact with a blade root. A cutting speed of the semi-finishing cutter may be increased and a cutting feed may be made faster, so work in a semi-finishing process may be performed efficiently. The rectangular tips and the square tips have simple shapes, so known commercially available throwaway tips may be used. Accordingly, it is possible to provide the semi-finishing cutter in an easy-to-use form without increasing the cost.

Abstract: A cutting tool is designed to prevent chip packing. The cutting tool includes a body that rotates about an axis center, a hole portion that is open in a tip end surface of the body, a wall portion that is formed of the hole portion and an outer circumferential surface of the body, a notch portion that is communicated with the hole portion, and a blade portion that is formed or held at a portion where the notch portion intersects with the tip end surface of the wall portion. The blade portion includes an inner side surface that passes through an inner end portion of a bottom blade and intersects with a rake surface through a ridge line. The inner side surface is inclined so that a distance between the inner side surface and the axis center is increased towards a direction opposite to the rotational direction of the body.

Abstract: In a rough cutting cutter, square tips and rectangular tips are disposed in a staggered pattern in an axial direction in second to fourth step portions, so a cutting edge is formed by a pair of one of the square tips and one of the rectangular tips. It is therefore possible to effectively reduce a frequency of contact with a blade root. Furthermore, in the second to a fifth step portions, ARs (rake angles in the axial direction) and RRs (rake angles in a radial direction) of the square tips and the rectangular tips gradually increase in order from a tip end to a back end of a tool body. It is therefore possible to suppress chatter vibration during machining and is possible to reduce roughness of a cut surface of a work material.

Abstract: A spiral fluted tap is provided which includes a threaded portion having an external thread corresponding to an internal thread to be cut and a cutting edge formed along a spiral flute formed to divide the external thread, and being screwed into a prepared hole that is provided on a workpiece to cut an internal thread by the cutting edge on an inner circumferential surface of the prepared hole with discharging chips toward a shank via the spiral flute, the spiral flute having a stepped portion at a rear end of a chamfer portion or in a portion on a shank side from the rear end of the chamfer portion in the threaded portion, and a flute bottom diameter on a distal end side of the spiral fluted tap from the stepped portion being smaller than a flute bottom diameter on a shank side from the stepped portion.

Abstract: A hard coating film formed on a surface of a predetermined member and having excellent wear resistance and adhesion resistance, the hard coating film includes: a three-layer structure composed of a third layer formed in contact with the surface of the predetermined member, a second layer formed on the third layer, and a first layer formed on the second layer to constitute the surface; the first layer being made of (Cr1-a-bBa(SiC)b)(CcOdN1-c-d) [provided that SiC is silicon carbide, and a, b, c and d are atomic ratios in ranges of 0?a?0.2, 0.01?b?0.2, 0?c?0.5 and 0?d?0.3, respectively; the second layer being made of AlCrN or AlCrDN [provided that D includes either one kind of elements of a Group IVa, a Group Va and a Group VIa (except Cr) of a Periodic Table of Elements and Y, or SiC (silicon carbide)]; and the third layer being made of nitride, carbon nitride or carbide of metals including elements of one kind or more kinds of Al, Ti, Zr, Hf, V, Nb, Ta, Cr and W.

Abstract: A throw-away rotating tool improves workability of detaching a throw-away tip and prevents from damaging a body. In the throw-away tool, a convex connection for the throw-away tip has protrusions, each of the protrusion includes a sliding contact portion detachably fitted into the inner peripheral groove recessed in the inner peripheral wall of a body. The protrusion has a first tilt portion continuous to the sliding contact portion. In detaching the throw-away tip from the body, the first tilt portion rotates ahead of the sliding contact portion, and a standing portion is elastically deformed due to a wedge effect of the first tilt portion. As a result, the protrusion can be gently removed from the inner peripheral groove.

Abstract: A DLC-coated fishing lure includes a fishing lure base material made of metal and having a predetermined shape; an intermediate layer made of one selected from a first group, a second group and a third group, the first group consisting of at least one kind of metal selected from the IIIb group, the IVa group, the Va group and the VIa group in the periodic table of elements, the second group consisting of at least one of a carbide, a nitride and a carbonitride of the at least one kind of metal, and the third group consisting of a mutual solid solution made of at least one selected from the first group and the second group, the intermediate layer being formed on a surface of the fishing lure base material; and a DLC layer having a thickness ranging from about 0.05 ?m to about 0.55 ?m and formed on the intermediate layer, the DLC layer presenting an appearance of a interference color.

Abstract: In cutting processes of a tree-shaped groove, in a rough cutting process, by using a rough cutting tool (20), as well as cutting a tapered groove (2), cutting is performed in a first narrow portion (11), a second narrow portion (12), and a third narrow portion (13) of a planned groove shape 10 such that a specified cutting allowance is left. In the following semi-finishing process, by using a semi-finishing tool, cutting is performed for portions other than the three narrow portions (11 to 13) that have already been cut. Because a work material 1 does not come in contact with three reduced diameter portions, of the semi-finishing tool formed in an upside-down Christmas tree shape, corresponding to the three narrow portions (11 to 13), a load is not imposed on the three reduced diameter portions, which are weak against shock among all portions of the semi-finishing tool, and the cutting feed can therefore be faster. Further, by performing a finishing process, the tree-shaped groove can be efficiently cut.

Abstract: In FIG. 2, a diameter Dd of drilling edges of a drill is selected smaller than a valley diameter d1 of a male thread of a tap portion, and an inner diameter D1 of a female thread is defined by the valley diameter d1 of the male thread. Therefore, a predetermined radial gap is formed between the male thread 30 formed by the tap portion and the drill. When a tap with the drill is reversely rotated to be pulled out from the female thread after cutting the female thread, the tap released from the restriction may deflectively displace in the diameter direction upon pulling out the male thread of the tap portion from the female thread. However, the drill hardly contacts with the female thread, so that the occurrence of the defective product due to the contact is suppressed.

Abstract: An apparatus for drilling a workpiece has a shaft portion including a holder to hold a drilling tool rotating around a first axis. A reduction gear is connected to the shaft portion. A cylindrical member, including an outer cylinder and an inner cylinder, rotatably contains the shaft portion at an eccentric position. The cylindrical member is connected to the output shaft of the reduction gear and rotated around a second axis parallel to the first axis. A slide containing cylinder contains the shaft portion, the reduction gear and the cylindrical member. The slide containing cylinder has a sliding structure for axially moving the shaft portion, the reduction gear and the cylindrical member. A drilling tool is simultaneously rotated around the first axis, revolved around the second axis and is axially moved.