MACHINE TOOL AND WORK-PIECE SUPPORT METHOD

To enable a tool to machine a peripheral surface of an end part of a lengthy work-piece while enhancing support rigidity of the work-piece.SOLUTION: A first chuck device 50 provided in a first spindle 10 and a second chuck device 60 provided in a second spindle 20 respectively comprise: a plurality of claw parts 52 and 62 which grip a peripheral surface Wa of an end part of a work-piece W; centers 53 and 63 that can advance and retreat in a direction of a rotation axis AX with respect to the claw parts 52 and 62 and can support end faces Wb1 and Wb2 of the work-piece W; and center advancing/retreating driving parts 55 and 65 that advance the centers 53 and 63 with respect to the claw parts 52 and 62. A control part 40, when the center advancing/retreating driving parts 55 and 65 advance the centers 53 and 63, in either of the first chuck device 50 and the second chuck device 60, controls a moving device 67 so that the centers 53 and 63 retreat either or both of the first spindle 10 and the second spindle 20 in the direction of the rotation axis AX while pressing the work-piece W in the direction of the rotation axis AX by force in a predetermined range.SELECTED DRAWING: Figure 1 【課題】長尺のワークの支持剛性を高めつつ、ワークの端部周面を工具により加工する。【解決手段】第1主軸１０に備える第１チャック装置５０、及び第２主軸２０に備える第２チャック装置６０のそれぞれは、ワークＷの端部周面Ｗａを把持する複数の爪部５２、６２と、爪部５２、６２に対して回転軸ＡＸ方向に進退可能であり、ワークＷの端面Ｗｂ１、Ｗｂ２を支持可能なセンタ５３、６３と、爪部５２、６２に対してセンタ５３、６３を前進させるセンタ進退駆動部５５、６５と、を備え、制御部４０は、第１チャック装置５０及び第２チャック装置６０の一方において、センタ進退駆動部５５、６５によりセンタ５３、６３を前進させる際、そのセンタ５３、６３がワークＷを回転軸ＡＸ方向に所定範囲の力で押圧しつつ第１主軸１０及び第２主軸２０の１つ又は双方を回転軸ＡＸ方向に後退させるように移動装置６７を制御する。【選択図】図１