Provided is a lathe capable of shortening the spindle. The lathe comprises a spindle, a spindle support which supports the spindle through a bearing on an outer side of the spindle, a collet disposed on a front end of the spindle, an inner ring holder provided on the spindle to hold a front of an inner ring of the bearing, an outer ring holder provided on the spindle support to hold a front of an outer ring of the bearing, a cap screwed into the spindle in front of the inner ring holder, and a cover detachably provided on the spindle support side. The cover has an inner circumferential surface facing an outer circumferential surface of the cap. A first air purging unit is provided between the inner circumferential surface of the cover and the outer circumferential surface of the cap.

Hollow shank tool holders including stress reduction features that result in a more reliable stronger tool holder are disclosed. The tool holders include an elliptical undercut contoured relief surface adjacent to the clamping surface to substantially reduce or eliminate a stress point. The elliptical undercut allows for no changes to be made to the clamping surfaces of the tool holder.

Hollow shank tool holders including stress reduction features that result in a more reliable stronger tool holder are disclosed. The tool holders include an elliptical undercut contoured relief surface adjacent to the clamping surface to substantially reduce or eliminate a stress point. The elliptical undercut allows for no changes to be made to the clamping surfaces of the tool holder.

A device for simultaneously measuring and adjusting the tool holding portion of a spindle. The device has a body defining a datum surface providing a magnetic portion and an indicator portion. A socket extends from the magnetic portion, the socket dimensioned and adapted to receive and seat a first component of the tool holding portion on the magnetic portion. A compressible indicator tip extends in an outward-biased manner from the indicator portion, wherein a distance from the distal end of the indicator tip and the indicator portion of the datum surface is displayed along the body.

Provided is a lathe capable of elongating the life of a shifter mechanism. A lathe comprises a spindle, a chucking unit, a power transmitting unit, a shifter, a claw, and a driving unit. The shape of an outer circumference of the shifter in a contact range and a first end of the claw in longitudinal section along the spindle axis is such shape as the acceleration a of the first end in the diameter direction with respect to the moving distance of the shifter moving in the direction of the spindle axis (Z-axis direction) at a constant speed is continuous both in a positive range and in a negative range where the contact range is a range of the outer circumference of the shifter in contact with the first end of the claw.

A facing head as well as a method for inserting a tool into and/or removing a tool from a tool holder device of the facing head. The facing head has a spindle coupling device for exchangeably coupling with a spindle chuck of a working spindle of a machine tool. The facing head has a housing body at which or in which a facing slide is moveably supported in a guided manner. The facing slide supports the tool holder device. The tool holder device is hydraulically controllable. A hydraulic coupling that is mechanically and hydraulically coupled with an associated hydraulic control coupling of the housing body in a tool change position of the facing slide. Remote from the tool change position, the mechanical and hydraulic connection between the hydraulic coupling and the associated hydraulic control coupling is interrupted. In the tool change position a switching of the tool holder device between a hold condition holding the tool and a release condition releasing the tool can be carried out by a respective pressurization with hydraulic pressure.

A cutter holder has a body and a retention knob connected to the body by threading. The body has a connecting hole having an internal threaded segment and a straight segment. The retention knob has a head, an abutting portion, and an external threaded portion. The abutting portion has a flange and an extending portion. The extending portion and the straight segment are in a clearance fit, and a sealing member seals the clearance between the extending portion and the straight segment. The external threaded portion is engaged with the internal threaded segment by threading, and has a first threaded segment and a second threaded segment. The first threaded segment is away from the head of the retention knob, and a tolerance class of the second threaded segment is higher than a tolerance class of the first threaded segment.

A flexible coupling for attaching a collet to a draw bar includes a draw bar having a first longitudinal axis and a first coupling portion. The first coupling portion includes two or more legs spaced apart from one another with each of the legs having first coupling surface formed thereon. The flexible coupling includes a collet having a second longitudinal axis and a clamping portion proximate one end of the collet. The collet includes a second coupling portion proximate a second end of the collet. The second coupling portion has a second coupling surface formed thereon and configured in a shape complementary to the first coupling surface so that the first coupling surfaces moveably engage the second coupling surface such that the first longitudinal axis and the second longitudinal axis are coaxial when an axial force is applied to the draw bar and the collet.

A rotating-tool main shaft includes a hollow ram, a hollow main shaft, a collet, a draw bar that moves the collet in the axial direction, a hydraulic cylinder that moves forwardly the draw bar, and a disc spring that moves backwardly the draw bar. The draw bar includes a spring catch which is retained in the hollow main shaft so as to be movable, and which catches the disc spring. The disc spring is placed in the hollow main shaft, and is placed within a distance that is at least a half of a distance from a tip of the draw bar to the spring catch in the axial direction.

A rotating tool is held in a tool holder. The tool holder includes a male tapered portion. The tool holder is rotated by a rotating-tool main shaft. The rotating-tool main shaft includes a hollow main shaft. The hollow main shaft includes a circular conical hole formed in a tip and corresponding to the male tapered portion. The hollow main shaft includes a fluid passage to detect that the male tapered portion is properly attached to the circular conical hole, and an opening to blow out a fluid. The opening is provided in a portion offset from the circular conical hole.