Provided is a replaceable machining head wherein:

fractures on the tool attaching portion do not occur; the production cost is minimized; the tool life of the working tool will be lengthened; and

the head body is free from a risk of falling off during replacement.

In the replaceable machining head 1, a cutting edge section 3 is formed on the front side of a head body;

a tool attaching portion 4 to which a working tool is to be attached, is formed on the rear end side of the cutting edge section 3;

tool attaching faces 4A are formed in the tool attaching potion 4;

the surface of the head body 1 is coated with a coating film; and

the number of droplets or macro particles having convex shapes with a size of 0.3µm to 5.0µm, is 200 or less, per area of 40µm×60µm on the surface of the coating film over the tool attaching faces 4A.

Provided are: an exchangeable tip cutting tool in which breakage of the threaded section and breakage of the thread ridges during installation of the machining head and under increased cutting load during cutting are limited and which is capable of performing machining with high efficiency; and a machining head and a holder to be used in the exchangeable tip cutting tool. The flank angle (α) of the pressure flank (11) is set to be larger than the flank angle (6) of the clearance flank (12); and a holder (2, 2a) having a female threaded fastening section (8) wherein the angle of the screwing surface of the pressure flank is set to be larger than the angle of the screwing surface of the clearance flank.

The holder for a head replacement-type cutting tool (1) is provided with a holder main body (2) and a tubular coupling member 3 which is housed in an attachment hole (4) formed on the holder main body (2) and made of a metal material lower in hardness than the holder main body (2). A recessed part is formed on an inner circumferential face of the attachment hole (4), the coupling member (3) is engaged with the recessed part by firmly attaching the outer circumferential face thereof on the inner circumferential face of the attachment hole (4), and the coupling member (3) is provided with an attachment screw part (3E) which is screwed into a head-side screw part (13) formed at the replacement-type cutting head (10).

The holder (1) is provided at the attachment hole (4) with the fitting part (4B) formed in a tapered shape, and the leading end face (2B) is perpendicular to the central axis (O). The attachment part (12) formed in a tapered shape protrudes on the cutting head (10) from the rear end face (11C) perpendicular to the central axis (O) of the cutting part (11). The cutting head (10) is attached to the holder (1) in such a manner that the attachment part (12) is fitted into the fitting part (4B) by screwing the female thread part (3E) with the male thread part (13) and the leading end face (2B) is in contact with the rear end face (11C). The inner diameter to outer diameter ratio d/D1 which is a ratio of the inner diameter d of the fitting part (4B) before being fitted in relation to the outer diameter D1 of the leading end part of the holder (1) is from 0.5 to 0.8. The outer diameter expansion percentage (D2 - D1)/D1 x 100 (%) formed by D2 - D1 which is a difference between the outer diameter D2 of the leading end part of the holder (1) after being fitted and the outer diameter D1 with respect to the outer diameter D1 is in a range of 0.022 x d/D1 - 0.003(%) to 0.33 x d/D1 - 0.06 (%).

Bei einem Kombifräswerkzeug zur Rückenbearbeitung von Buchblocks mit einem kreisförmigen, rotierbar antreibbaren Grundkörper ist es vorgesehen, dass der Grundkörper und koaxial auf dem Grundkörper gelagerte Ringe Werkzeuge tragen, wobei die Ringe mittels Gewindegängen ineinander gelagert sind. Zur Arretierung weist jeder Ring eine Anzahl Druckschrauben auf, mit welchen der Ring am Grundkörper arretierbar ist.

A cutting tool, and a loose top therefore, includes two parts detachably connected to each other via a threaded joint in which co-operating male and female threads are included in the form of helicoidal ridges. The profile shape of each helicoidal ridge is defined by a top and two flanks, which delimit a helicoidal groove having a bottom. The first flank is inclined in relation to a center axis of the tool at a first angle that is smaller than a second angle of the second flank in relation to the center axis. Accordingly, the thread ridge is reinforced in comparison with thread ridges having a symmetrical profile shape, whereby larger tensile forces than compressive forces can be applied to the threaded joint while avoiding damage to the thread ridges.

A cutting tool (1), and a loose top (2) therefore, includes two parts (1,2) detachably connected to each other via a threaded joint in which co-operating male and female threads (10;11) are included in the form of helicoidal ridges (10;11). The profile shape of each helicoidal ridge (10;11) is defined by a top (21;21a) and two flanks (22,23;22a,23a), which delimit a helicoidal groove (24;24a) having a bottom (25;25a). The first flank (22;22a) is inclined in relation to a center axis (C) of the tool at a first angle (α) that is smaller than a second angle (β) of the second flank (23;23a) in relation to the center axis (C). Accordingly, the thread ridge (10;11) is reinforced in comparison with thread ridges having a symmetrical profile shape, whereby larger tensile forces than compressive forces can be applied to the threaded joint while avoiding damage to the thread ridges (10;11).