Abstract: A multi-spindle machining machine with a tool changing mechanism contains a base; a carrier including a seat to move in Z axis, a rotary shaft fixed on the seat laterally to drive the seat to rotate in A axis, and a fixing holder coupled to an end portion of the rotary shaft to fix a work piece; a tool changing mechanism including a mount mounted to the rotary shaft to rotate with the rotary shaft and a monitor fixed on the seat to measure a length of the tool clamped on a driving spindle, and including a plurality of slots to receive the tools respectively; a working head moving above the carrier and the tool changing mechanism in X and Y axes and including the driving spindle mounted on a lower end thereof to rotate axially, and the lower end of the driving spindle allowing to engage and disengage the tool.

Abstract: It is an object of the invention to provide a tap holder in which even when an error is brought about in synchronizing spindle feeding and rotation of a tapper body and a tap collet of a tap holder in correspondence with a machine tool spindle, the spindle feeding and rotation can be synchronized by absorbing the error by a simple constitution. As means therefor, a tap holder including a tap collet for chucking a tap at one end thereof, a tapper body formed with an attaching hollow portion for inserting other end of the tap collet, and a fastening nut for pressing the tap collet to the attaching hollow portion to be fixed to the tapper body by being screwed with the tapper body and engaged with one end side end face of the tap collet, and attached to a machine tool having a tap synchronizingly feeding mechanism is characterized in that the tap collet is squeezed by a bottom face of the attaching recessed portion and the fastening nut by way of elastic members in an axial direction.