Abstract: A thread forming tap having a complete thread portion, formed with a predetermined back taper with that decreases rotational torque during tapping work, which reduces load acting on first complete protruding portions, formed at an extreme leading end of the complete thread portion, and thereby suppressing degradation in service life of the tool due to wear.

Abstract: Disclosed herein is an electrolytic erosion preventing insulated rolling bearing and a manufacturing method thereof. In one embodiment, the electrolytic erosion preventing insulated rolling bearing includes an insulating coating being a ceramic coating layer including alumina as the main component and 0.01 to 0.2 percent by weight titanium oxide with the alumina having a particle size ranging from 10 to 50 ?m and average particle size ranging from 15 to 25 ?m.

Abstract: A shrink-fit tool unit increases the transmission force of rotary power and also improves workability when inserting the rotary tool into the tool holder. A tool holder and a rotary tool to be used for the shrink-fit tool unit are also disclosed. Since a first engaging part and a second engaging part are configured to engage with each other simply by inserting a cylindrical terminal area of a rotary tool, typically, a thread forming tap, into a chuck of the tool holder, even when the machining load receiving from a work piece act both in forward and reverse directions relative to the circumferential direction, it is possible to increase the transmission of rotary power.

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: A polishing composition that allows polishing speed to be increased and surface roughness to be reduced is provided. The polishing composition according to the present invention includes a compound including at least an oxyethylene group or an oxypropylene group in a block polyether represented by the following general formula (1), a basic compound, and abrasives: >N—R—N< (1) where R represents an alkylene group expressed as CnH2n and “n” is an integer not less than 1.

Abstract: A thread forming tap having a complete thread portion, formed with a predetermined back taper with that decreases rotational torque during tapping work, which reduces load acting on first complete protruding portions, formed at an extreme leading end of the complete thread portion, and thereby suppressing degradation in service life of the tool due to wear or the like

Abstract: A polishing composition that can improve polishing property without foaming is provided. A polishing composition includes a pH regulator, a water-soluble polymer compound, and a compound containing an alkylene diamine structure having two nitrogens represented by the following general formula (1), and having at least one block type polyether bonded to the two nitrogens of the alkylene structure, the block type polyether having a bond of an oxyethylene group and an oxypropylene group: where R represents an alkylene group represented by CnH2n, in which n is an integer of 1 or more.

Abstract: As shown in FIG. 1, rake surfaces of cutting edges 26 of a shank-side thread portion 24b formed in a full thread portion 24 are formed with chamfers 30 having the chamfer height Hmen fallen within the range of 15% to 100% of the thread height Hneji. This allows chips to be further easily pushed out toward an outer circumferential area along the chamfers 30. In addition, the cutting edges 26 can have the increased strength thanks to formation of the chamfers 30. This effectively prevents occurrence of chipping and breakage resulted from the biting of the chips. Further, the chamfer-side thread portion 24a formed on the full thread portion 24 at the distal end is contiguous to the chamfer portion 22, which has an original complete thread configuration with more than one thread and not more than five threads. In addition, the shank-side thread portion 24b formed with the chamfers 30 has an original thread configuration except areas around the cutting edges 26.

Abstract: In order to ensure high levels of insulation performance, and low cost, and have an excellent external appearance, as a ceramic constituting an insulating coating 6 being a ceramic coating layer, one with alumina as its main component, and in which the content of titanium oxide is limited to 0.01 to 0.2 percent by weight is used. Moreover, a particle size of ceramic forming the coating layer is 10 to 50 ?m, and average particle size is 15 to 25 ?m. By limiting the content of titanium oxide, the insulating coating 6 can be made thin, and by limiting the particle size the film thickness accuracy can be improved, thus simplifying finishing. Moreover, by mixing of titanium oxide, deterioration of the external appearance after sealing can be prevented. As a result, the above problem is solved.

Abstract: A shrink-fit tool unit increases the transmission force of rotary power and also improves workability when inserting the rotary tool into the tool holder. A tool holder and a rotary tool to be used for the shrink-fit tool unit are also disclosed. Since a first engaging part and a second engaging part are configured to engage with each other simply by inserting a cylindrical terminal area of a thread forming tap into a chuck 22 of the tool holder, even when the machining load receiving from a work piece act both in forward and reverse directions relative to the circumferential direction, it is possible to increase the transmission of rotary power.

Abstract: A drilling and thread-milling tool for generating an internal thread in a workpiece, including a proximal shank portion attachable to a driving device for rotating the tool about a rotation axis thereof, and a distal cutting portion rotated with the shank portion about the rotation axis for generating the internal thread while the distal cutting portion is moved relative to the workpiece. The cutting portion has at least one thread-milling tooth on an outer circumferential surface thereof, each tooth having a configuration similar to that of the internal thread, and a height substantially equal to a depth of the internal thread. The cutting portion further has at least one end-cutting edge on a distal end face thereof so as to extend in a radial direction thereof, each end-cutting edge having a maximum diameter which is larger and smaller than a minor diameter and a major diameter of the thread-milling tooth.