A milling tool body is rotatable around a central rotation axis and includes a front end surface and a rear end surface. An envelope surface surrounds the axis and extends between the rear end surface and the front end surface. A plurality of insert pockets are formed in a transition between the envelope surface and the front end surface. A first central through-hole of constant diameter extends between the rear end surface and the front surface. The locking disc has a second central through-hole and a fastening device is arranged to extend through the second central through-hole. The locking disc is arranged to press against the front end surface of the milling tool body when mounting the milling tool body to an adaptor by the fastening device. The fastening device is mountable to an end of the adaptor insertable into the first central through-hole.

Improvements in a self-balancing tool holder or material removal machine that allows for greater accuracy of material removal. The balancer is able to self-adjust, any changes in the assembly are automatically adjusted. The adjustment can account for tool wear, accumulation of debris on the tool and balancing at different speeds of rotation. The tool holder balancer can be a mechanical fastener, shrink fit or bonding to the tool holder or material removal machine. The balancer uses a plurality of balls or any form of movable weight in the ring to provide the balance. The plurality of balls or media can freely move around the inside of the ring to offset any imbalance. The balls roll or spin to unique positions to provide a dynamic balance. The number and size of balls or weighted media is selected based upon the maximum amount of dynamic balancing that is required.

An electrodynamic acoustic transducer (1) is disclosed, which comprises a frame and/or a housing (2), a membrane (3), a magnet system (6) with a plurality of center magnets (7a . . . 7d, 7, 7′) having different magnetic orientations (M.sub.1 . . . M.sub.4) and a coil arrangement (10) with a plurality of voice coils (11a . . . 11d), which are movably arranged relative to the magnet system (6) in an excursion direction (z). The ratio

[00001]$\frac{A_g.Math.h_m}{A_m.Math.w_g}=\frac{l_g.Math.h_{\mathrm{tp}}.Math.h_m}{A_m.Math.w_g}$

is below 1, wherein w.sub.g denotes the mean width of all airgaps (E) within the magnet system (6), A.sub.g denotes the sum of all airgap areas within the magnet system (6), h.sub.m denotes the mean height of the center magnets (7a . . . 7d, 7, 7′) and A.sub.m denotes the total area of the center magnets (7a . . . 7d, 7, 7′). Moreover, the invention relates to an electroacoustic system (19), which comprises an electrodynamic acoustic transducer (1) of the above kind and a control circuit (CC) connected to the coil arrangement (10).

In a T-shaped tool (10) in which a head (30) having cutting edges (36, 38) and a cylindrical shank (20) are fastened together: the shank comprises a super-hard alloy, and an engaging portion which engages with a tool main body is formed in a distal end portion thereof; the tool main body comprises a steel material, and an engaged portion which engages with the engaging portion of the shank is formed therein; and the engaging portion and the engaged portion are fastened in such a way as to be retained and prevented from rotating.

A cutter holding assembly has a holder, a cutter, and a tightening positioning assembly. The holder has a first positioning recess. The cutter is connected to the holder and has a second positioning recess. The tightening positioning assembly has a positioning block, two tightening elements, and an adjusting element. The positioning block is mounted in the first positioning recess of the holder and the second positioning recess of the cutter. The tightening elements are mounted in two opposite sides of the positioning block. The adjusting element is mounted in the positioning block at a position between the two tightening elements. The adjusting element has a conical abutting surface for pushing the tightening elements to move opposite to each other to abut the opposite side surfaces of one of the first and the second positioning recesses while axially moving. The cutter can be firmly connected to the holder.

A cutter holding assembly has a holder, a cutter, and a tightening positioning assembly. The holder has a first positioning recess. The cutter is connected to the holder and has a second positioning recess. The tightening positioning assembly has a positioning block, two tightening elements, and an adjusting element. The positioning block is mounted in the first positioning recess of the holder and the second positioning recess of the cutter. The tightening elements are mounted in two opposite sides of the positioning block. The adjusting element is mounted in the positioning block at a position between the two tightening elements. The adjusting element has a conical abutting surface for pushing the tightening elements to move opposite to each other to abut the opposite side surfaces of one of the first and the second positioning recesses while axially moving. The cutter can be firmly connected to the holder.

An assembly of a tool and a tool holder may include the tool, which may have an elongated body with a socket, and the tool holder, which may have a body with a first bore configured to receive at least a portion of the elongated body, and a second bore substantially transverse to the first bore. The assembly may also have an impinging member including a body having an end with a radial surface. In an assembled state, a portion of the elongated body of the tool may be positioned within the first bore of the body of the tool such that the socket and the second bore may be substantially aligned, and the body of the impinging member may be positioned within the second bore with the radial surface pressed against the elongated body in the socket at a predetermined torque.

A rotating tool includes a tool body having an axis of rotation and a first recess for receiving an ID chip having a first mass and a first exterior geometry. The tool includes a dummy chip receivable in the first recess and the tool is rotationally balanced with the dummy chip in the first recess, wherein after balancing the dummy chip is removed and the ID chip is insertable in the first recess.

A milling tool has a shank and a milling portion arranged along a longitudinal axis of the milling tool. The milling portion has at least one peripheral blade and a flute that adjoins a cutting edge of the peripheral blade. A radial spacing between the cutting edge and the longitudinal axis is selected on the basis of a specified compensation rotational speed such that a shell surface formed by the rotating cutting edge is circular cylindrical in the case of a rotation of the milling tool at the compensation rotational speed. The radial spacing of the cutting edge increases continuously or decreases continuously as the distance from the shank increases.

An attrition liner machining tool, configured to machine the surface of an attrition liner provided radially outward of a set of a plurality of fan blades in a gas turbine engine. The tool includes at least one rotating machine tool having a connector at a first end and a cutter at a second end. The connector is configured to rigidly connect to a rotating fan blade mount of the gas turbine engine that, in use of the gas turbine engine, supports the fan blades. The cutter is configured to machine the attrition liner. The at least one rotating machine tool is configured such that, when it is connected to said rotating fan blade mount of a gas turbine engine, the cutter is passed across the surface of the attrition liner when said rotating fan blade mount is rotated.