Used Index Cnc Lathe for sale (136)

Year of construction: 1995, condition: ready for operation (used), Max. speed range: 5000 rpm, bar capacity: 65 mm, max. turning diameter: 200 mm, max. turning length: 400 mm. Number of spindles: 2, tool changer: 2x 14, Siemens control. Including outfeed conveyor, KNOLL 400S-1 chip conveyor (year of manufacture: 2016), switch cabinet with cooling unit, CO2 extinguishing system and INDEX bar loader. General overhaul in 2016. Bodpfxotdwwmo Abcjwh

Year of construction: 2003, condition: ready for operation (used), Max. turning diameter: 200mm, max. turning length: 400mm, spindle speed: 6000rpm, bar capacity: 42mm, weight: approx. 4300kg. Bwodpfx Ajtdwwqebcoh

Year of construction: 2002, condition: ready for operation (used), A CNC multi-spindle lathe Index overhauled in 2020 is available. Number of spindles: 6, max. bar capacity: 32mm, spindle speed: 6300rpm, weight: approx. 10800kg, control: Siemens Sinumerik. Bearing condition measurement 2024 HS1: 14.35, HS2: 15.45, HS3: 10.37, HS4: 11.16, HS5: 17.44, HS6: 7.54. The machine has undergone extensive repairs to the spindles, cooling system, bearings, hydraulic lines, etc. Documentation available. Documentation available. On-site inspection is possible. Bwodpfx Abjwr Dw Rjceh

Condition: new, Index MS32 DRIVE Z-NC SPK1 Item ID: GM2602.1551 Ball Screw Item ID: 10912112 Previous Item ID: GM2602.1551 From stock/wear - Offer as shown in pictures - Bwjdpfx Aswb Evmsbcoh

Condition: used, Year of construction: 2007, turning diameter 140 mm turning length 615 mm control C200-4D spindle passage 65 mm turning speeds 5.000 U/min max. torque at 40% / 100% load 145 / 105 kW turret-slide 1,2 und 3 x-travel 110 mm z-travel 360 mm y-travel 70 mm Bwsdpfxewzynqj Abceh rapid traverse X/Y/Z 25/12/45 m/min slide travel X-axis 150 mm Z- Travel 600 mm turning speeds 5.000 U/min B - axis B-Korrekturachse +/- 1 ° tool turret - number of stations 3 x 12 tool taper DIN 69880 VDI 25 x 48 C-axis 0,001 ° total power requirement 61 kW weight of the machine ca. 6,5 t dimensions of the machine ca. 9,75 x 3,10 x 2,85 m Loading: Breuning Profimat 65.8x270/8 multi-channel loading magazine, built in 2005 for bars with lengths of 500–3,000 mm, 8 guide channels with spindle insert tubes (Ø 16, 25, 30, 40, 45, 55, 60, 65 mm) Unloading: BREUNING ILS-REX-7208 automatic workpiece unloader, built in 2007

Condition: used, Year of construction: 1996, functionality: fully functional, turning length: 800 mm, turning diameter: 280 mm, spindle bore: 65 mm, travel distance X-axis: 310 mm, travel distance Z-axis: 870 mm, spindle motor power: 22,000 W, rotational speed (max.): 4,000 rpm, total height: 2,200 mm, total length: 4,100 mm, total width: 2,000 mm, overall weight: 4,600 kg, swing diameter over bed slide: 400 mm, chuck outer diameter: 315 mm, Equipment: documentation/manual, rotational speed infinitely variable, We are happy to assist you with your inquiries by phone. Bsdpfjw Nn Eljx Abcjwh

Condition: used, Cnc multispindle lathe INDEX MS32C Bjdpfx Ajxma Npsbcowh

Condition: used, TECHNICAL DETAILS - Number of spindles : 6 - Max. bar diameter : 32 [mm] Bwjdpfeuhatpsx Abcsh - Spindle speed : 6300 [rpm] - slide unity 1.1 : X and Z axes controlled by CNC - slide unity 1.2 : X and Z axes controlled by CNC - slide unity 2.1 : X and Z axes controlled by CNC - slide unity 2.2 : X and Z axes controlled by CNC - slide unity 3.1 : X and Z axes controlled by CNC - slide unity 3.2 : X and Z axes controlled by CNC - slide unity 4.1 : X and Z axes controlled by CNC - slide unity 4.2 : X and Z axes controlled by CNC - slide unity 5.1 : X and Z axes controlled by CNC - slide unity 5.2 : X and Z axes controlled by CNC - slide unity 6.1 : X and Z axes controlled by CNC - slide unity 6.2 : X and Z axes controlled by CNC - synchronous unit, spindle position 6.1 EQUIPMENT - CN SIEMENS 840D - Counter spindle - Polygonal milling device : 5.1 carriage unit - Bar loader : IEMCA SIR MS32/33 P - coolant tank KNOLL * with high-pressure pump - chip conveyor KNOLL - Cooling unit - Parts catcher - Ejection of workpiece - Fire extinguisher : KRAFT UND BAUER * NB : working order not guaranteed. To have it checked by a qualified organization of the buyer

Condition: used, TECHNICAL DETAILS - Number of spindles : 6 - Max. bar diameter : 32 [mm] - Spindle speed : 6300 [rpm] - slide unity 1.1 : X and Z axes controlled by CNC - slide unity 1.2 : X and Z axes controlled by CNC - slide unity 2.1 : X and Z axes controlled by CNC - slide unity 2.2 : X and Z axes controlled by CNC - slide unity 3.1 : X and Z axes controlled by CNC - slide unity 3.2 : X and Z axes controlled by CNC - slide unity 4.1 : X and Z axes controlled by CNC - slide unity 4.2 : X and Z axes controlled by CNC - slide unity 5.1 : X and Z axes controlled by CNC - slide unity 5.2 : X and Z axes controlled by CNC - slide unity 6.1 : X and Z axes controlled by CNC - slide unity 6.2 : X and Z axes controlled by CNC - synchronous unit, spindle position 6.1 EQUIPMENT - CNC Siemens 840D - Counter spindle - Double control panel - 2 NCU - Bar loader : IEMCA SIR MS32 F Bwjdpfxjuhavde Abcoh - Coolant tank : KNOLL * with high pressure pump - Chip conveyor : KNOLL - Cooling unit: Riedel WTS 030.02-NE - Unloading system with 2 CNC axes - Fire extinguisher : KRAFT UND BAUER *NB : working order not guaranteed. To have it checked by a qualified organization of the buyer.

Condition: used, TECHNICAL DETAILS - number of spindles : 6 independent - bar clearance : 32 [mm] - maxi spindle speed : 6 300 [rpm] - machine equipped with 32 numerical axes - slide unity 1.1 : X and Z axes controlled by CNC - slide unity 1.2 : fixed X axis, Z axis controlled by CNC - slide unity 2.1 : fixed X axis, Z axis controlled by CNC - slide unity 2.2 : X and Z axes controlled by CNC - slide unity 3.1 : X and Z axes controlled by CNC - slide unity 3.2 : fixed X axis, Z axis controlled by CNC - slide unity 4.1 : X and Z axes controlled by CNC - slide unity 4.2 : fixed X axis, Z axis controlled by CNC - slide unity 5.1 : fixed X axis, Z axis controlled by CNC - slide unity 5.2 : X and Z axes controlled by CNC - slide unity 6.1 : X and Z axes controlled by CNC - slide unity 6.2 : X and Z axes controlled by CNC - counter-spindle position 6.1 Bwedpfsuhaxlox Abcsh EQUIPMENT - INDEX C200-4 control (Siemens SINUMERIK 840D) - Simple NCU - IEMCA SIR MS32/33/P bar loader - Coolant tank with HP pump - KNOLL chips conveyor - Parts catcher with conveyor in position 6 - Cross drilling device in position 3.1 et 4.1

Condition: used, TECHNICAL DETAILS - Number of spindles : 6 - Max. bar diameter : 32 [mm] - Spindle speed : 6300 [rpm] - slide unity 1.1 : X and Z axes controlled by CNC - slide unity 1.2 : X and Z axes controlled by CNC - slide unity 2.1 : X and Z axes controlled by CNC - slide unity 2.2 : X and Z axes controlled by CNC - slide unity 3.1 : X and Z axes controlled by CNC - slide unity 3.2 : X and Z axes controlled by CNC - slide unity 4.1 : X and Z axes controlled by CNC - slide unity 4.2 : X and Z axes controlled by CNC - slide unity 5.1 : X and Z axes controlled by CNC - slide unity 5.2 : X and Z axes controlled by CNC - slide unity 6.1 : X and Z axes controlled by CNC - slide unity 6.2 : X and Z axes controlled by CNC - synchronous unit, spindle position 6.1 EQUIPMENT - CN SIEMENS 840D - Counter spindle - Polygonal milling device : 5.1 carriage unit Bwodouhatcspfx Abcjh - Bar loader : IEMCA SIR MS32/33 P - coolant tank KNOLL * with high-pressure pump - chip conveyor KNOLL - Cooling unit - Parts catcher - Ejection of workpiece - Fire extinguisher : KRAFT UND BAUER * NB : working order not guaranteed. To have it checked by a qualified organization of the buyer

Condition: used, TECHNICAL DETAILS - Spindle power : 10,5 [kW] - Spindle speed : 10 000 [Rpm] - Spindle type : A2-4 - X/Y/Z strokes : 280/280/145 [mm] - Rapid traverse : 50 [m/min] - Loading zone X/Z strokes : 110/90 [mm] - Number of tools : 8 - Live tools speed : 6000 [Rpm] - Live tools power : 9,5 [kW] - Tool type : Capto C4 - Dimensions : 1700 x 3000 x 2400 [mm] - Weight : 4000 [kg] - Total installed power : 2,5 [kW] EQUIPMENT Bedpjuhbgwefx Abcswh - CN Siemens 840D - Axis C

Condition: used, TECHNICAL DETAILS - Number of axes : 7 - Number of spindles : 2 - Number of turrets : 1 MAIN SPINDLE - Spindle nose : A2-5 - Spindle power : 22 [kW] - Spindle speeds : 6000 [rpm] - Max. bar diameter : 60 [mm] - Max. turning diameter : 200 [mm] - C axis indexing precision : 0.001 [°] COUNTER-SPINDLE - Spindle nose : A2-5 - Spindle power : 22 [kW] - Spindle speeds : 6000 [rpm] - Max. bar diameter : 60 [mm] - C axis indexing precision : 0.001 [°] - Z stroke : 445 [mm] TURRET 1 - Number of positions : 14 - Number of motorized positions : 14 - X/Z stroke : 105/400 [mm] - Y stroke : 120 [mm] - B Axis stroke : +90/-270 [°] - Tool type : VDI 25 - Live tools speed : 6000 [rpm] - Live tools power : 5.5 [kW] POWER SUPPLY - Supply voltage : 400 [V] WEIGHT & DIMENSIONS - Machine floor space : 4.975 X 2.890 [mm] Bwedpfou Hadhjx Abcjh - Machine height : 2.050 [mm] - Machine weight : 4800 [kg] EQUIPMENT - CNC : Siemens 840C - Coolant tank * with high-pressure pump - Chips conveyor - Parts catcher - Parts conveying strip - Bar loader : LNS

Condition: used, TECHNICAL DETAILS - Spindle power : 10,5 [kW] - Spindle speed : 10 000 [Rpm] - Spindle type : A2-4 - Strokes X/Y/Z : 280/280/145 [mm] - Quick movement : 50 [m/min] - Loading zone strokes X/Z : 110/90 [mm] Bodjuhbfmspfx Abcswh - Tools number : 8 - Motorized tools number : 2 - Rotary tools speed : 6000 [tr/min] - Rotary tools power : 9,5 [kW] - Tools type : Capto C4 - Dimensions : 1700 x 3000 x 2400 [mm] - Weight : 4000 [kg] - Installed power : 2,5 [kW] EQUIPMENT - CN Siemens 840D - Axis C - Measuring rules on linear axes - Counter spindle - 1 turning tool holder for counter operation - Coolant tank with pump - Chip conveyor

Condition: used, TECHNICAL DETAILS - Number of axes : 6 - Number of spindles : 1 MAIN SPINDLE - Spindle nose : A2-5 - Spindle power : 20/27 [kW] - Spindle speeds : 6300 [rpm] - Max. bar diameter : 42 [mm] - Max. diameter on bench : 200 [mm] - Max. chuck diameter : 160 [mm] - C axis indexing precision : 0.001 [°] UPPER TURRET * Number of positions : 12 * Number of motorized positions : 12 - Tool type : VDI 25 * Live tools speed : 6000 [rpm] * Live tools power : 8 [kW] LOWER TURRET - Number of positions : 12 - Number of motorized positions : 12 - X/Z stroke : 110/800 [mm] - Tool type : VDI 25 - Live tools speed : 6000 [rpm] - Live tools power : 5,5 [kW] TAILSTOCK - Tailstock type : Numérique POWER SUPPLY - Supply voltage : 400 [V] - Total installed power : 43 [kW] WEIGHT & DIMENSIONS - Machine floor space : 4435x1950 [mm] - Machine height : 1930 [mm] - Machine weight : 7500 [kg] EQUIPMENT - CNC : INDEX C200-4D - Linear scales Bsdsuhacdepfx Abcswh - Coolant tank * with high-pressure pump : 80 [bars] * with paper filtering unit - Chips conveyor - Oil mist extractor - Chuck 3 jaws

Condition: used, Cnc multispindle lathe INDEX MS 32 C Bwodeuhaqbepfx Abcjh

Condition: used, TECHNICAL DETAILS - Number of spindles : 6 - Max. bar diameter : 32 [mm] - Spindle speed : 6300 [rpm] - slide unity 1.1 : X and Z axes controlled by CNC - slide unity 1.2 : X and Z axes controlled by CNC - slide unity 2.1 : X and Z axes controlled by CNC - slide unity 2.2 : X and Z axes controlled by CNC - slide unity 3.1 : X and Z axes controlled by CNC - slide unity 3.2 : X and Z axes controlled by CNC - slide unity 4.1 : X and Z axes controlled by CNC - slide unity 4.2 : X and Z axes controlled by CNC - slide unity 5.1 : X and Z axes controlled by CNC - slide unity 5.2 : X and Z axes controlled by CNC - slide unity 6.1 : X and Z axes controlled by CNC - slide unity 6.2 : X and Z axes controlled by CNC - synchronous unit, spindle position 6.1 EQUIPMENT - CN SIEMENS 840D - Counter spindle - Polygonal milling device : 5.1 carriage unit - Bar loader : IEMCA SIR MS32/33 P - coolant tank KNOLL * with high-pressure pump - chip conveyor KNOLL - Cooling unit - Parts catcher - Ejection of workpiece Bjdpfsuhar Sex Abcjwh - Fire extinguisher : KRAFT UND BAUER * NB : working order not guaranteed. To have it checked by a qualified organization of the buyer

Condition: used, TECHNICAL DETAILS - Number of spindles : 6 - Max. bar diameter : 32 [mm] - Spindle speed : 6300 [rpm] - slide unity 1.1 : X and Z axes controlled by CNC - slide unity 1.2 : fixed X axis, Z axis controlled by CNC - slide unity 2.1 : X and Z axes controlled by CNC - slide unity 2.2 : X and Z axes controlled by CNC - slide unity 3.1 : X and Z axes controlled by CNC - slide unity 3.2 : X and Z axes controlled by CNC - slide unity 4.1 : X and Z axes controlled by CNC - slide unity 4.2 : fixed X axis, Z axis controlled by CNC - slide unity 5.1 : X and Z axes controlled by CNC - slide unity 5.2 : X and Z axes controlled by CNC - slide unity 6.1 : X and Z axes controlled by CNC - slide unity 6.2 : X and Z axes controlled by CNC - synchronous unit, spindle position 6.1 EQUIPMENT - CN SIEMENS 840D - Counter spindle Bwjdpfxsuhaumo Abceh - Bar loader : IEMCA SIR MS32/33 P - coolant tank KNOLL * with high-pressure pump - chip conveyor KNOLL - Parts catcher - Ejection of workpiece - Fire extinguisher : KRAFT UND BAUER * NB : working order not guaranteed. To have it checked by a qualified organization of the buyer

Condition: used, TECHNICAL DETAILS - number of spindles : 6 independent - bar clearance : 32 [mm] - maxi spindle speed : 6 300 [rpm] - machine equipped with 28 numerical axes - slide unity 1.1 : X and Z axes controlled by CNC - slide unity 2.2 : X and Z axes controlled by CNC - slide unity 3.1 : X and Z axes controlled by CNC - slide unity 3.2 : X and Z axes controlled by CNC - slide unity 4.1 : X and Z axes controlled by CNC - slide unity 4.2 : X and Z axes controlled by CNC - slide unity 5.1 : X and Z axes controlled by CNC - slide unity 5.2 : X and Z axes controlled by CNC - slide unity 6.1 : X and Z axes controlled by CNC - slide unity 6.2 : X and Z axes controlled by CNC - synchronous unit, spindle position 6.1 Bwsdouhauyepfx Abcjh EQUIPMENT - INDEX C200-4 control (Siemens SINUMERIK 840D) - Simple NCU - IEMCA SIR MS32/33/P bar feeder - Coolant tank: KNOLL AE 1076 * with high-pressure pump - KNOLL VRF 500 chips conveyor - Parts catcher with conveyor in position 6

Condition: used, TECHNICAL DETAILS - Spindle power : 10,5 [kW] - Spindle speed : 10 000 [Rpm] - Spindle type : A2-4 - X/Y/Z strokes : 280/280/145 [mm] - Rapid traverse : 50 [m/min] - Loading zone X/Z strokes : 110/90 [mm] - Number of tools : 8 - Live tools speed : 6000 [Rpm] - Live tools power : 9,5 [kW] - Tool type : Capto C4 - Dimensions : 1700 x 3000 x 2400 [mm] - Weight : 4000 [kg] - Total installed power : 2,5 [kW] EQUIPMENT - CN Siemens 840D - Axis C Bodjuhbf Tspfx Abcewh

Condition: used, TECHNICAL DETAILS - Number of spindles : 2 - Number of axes : 8 - Number of turrets : 2 MAIN SPINDLE - Spindle power : 53 / 68 [kW] - Spindle speeds : 3000 [rpm] - Max. bar diameter : 102 [mm] - 1 - Saisie libre : 2000 [mm] - Max. chuck diameter : 420 [mm] - Rapid traverse rate : 30 [m/min] - C axis indexing precision : 0,001 [°] Bsdpfx Absuhbpfjcowh COUNTER-SPINDLE - Spindle power : 50 / 70.5 [kW] - Spindle speeds : 3000 [rpm] - Max. bar diameter : 102 [mm] - Rapid traverse rate : 30 [m/min] - C axis indexing precision : 0,001 [°] UPPER LEFT TURRET - Number of positions : 12 - Number of motorized positions : 12 - Tool holder type : VDI 40 - X/Z stroke : 320 x 2.000 [mm] - Y stroke : 210 [mm] - Live tools speed : 6000 [rpm] - Live tools power : 17 [kW] LOWER RIGHT TURRET - Number of positions : 10 - Number of motorized positions : 10 - Tool holder type : VDI 40 - X/Z stroke : 210 x 2.000 [mm] - Live tools speed : 6000 [rpm] - Live tools power : 11.3 [kW] POWER SUPPLY - Supply voltage : 400 [V] - Total installed power : 137 [kW] WEIGHT & DIMENSIONS - Machine floor space : 9.000 x 3.500 [mm] - Machine height : 3.000 [mm] - Machine weight : 21.000 [kg] MACHINE HOURS - Number of working hours : 34274 [h] EQUIPMENT - CNC : INDEX C200-4D (Siemens 840D) - Coolant tank : KNOLL * with high-pressure pump : 80 [bars] * with paper filtering unit - Automatic doors - Chips conveyor : Droite

Condition: used, TECHNICAL DETAILS - Quantity of spindles : 6 - Bar clearance : 40 [mm] - Rotation speed : 7 000 [rpm] - Spindle power : 13 / 24 [kW] NUMERICAL AXES : 27 - Slides unit 1.1 : axes X and Z CNC-controlled - Slides unit 1.2 : axes X and Z CNC-controlled - Slides unit 2.1 : axes X and Z CNC-controlled - Slides unit 2.2 : axes X and Z CNC-controlled - Slides unit 3.1 : axes X and Z CNC-controlled - Slides unit 3.2 : axis Z CNC-controlled - Slides unit 4.1 : axes X and Z CNC-controlled - Slides unit 4.2 : axis Z CNC-controlled - Slides unit 5.1 : axes X and Z CNC-controlled - Slides unit 5.2 : axis Z CNC-controlled - Slides unit 6.1 : axis Z CNC-controlled + SCARA axis - Slides unit 6.2 : axes X and Z CNC-controlled - Slides unit 6.3 : axis X CNC-controlled ELECTRICAL INPUT - Voltage : 400 [V] - Frequency : 50 [Hz] - Installed power : 65 [kW] DIMENSIONS OF THE MACHINE - Floor space : 3329 x 2032 [mm] - Height : 2654 [mm] - Weight: 7100 [kg] HOURS - Hours under power : 45965 - Production hours : 19065 EQUIPMENT - CNC Siemens 840D (PL) double NCU - 2 control panels CN - 6 collet receivers TOPLUS with built-in stop - 1 counter-spindle in position 6.1 - Clamping device in counter-spindle : chuck Röhm KFD-HS 110/3 - Coolant through counter-spindle center - Cn options counter-spindle/ polygonal milling - Rear machining device on slide 6.2 : 3x fix - Preparation 2 additional controls with electronic shaft in position 1.2.3 - Preparation 2 additional controls with electronic shaft in position 4.5.6 - STAUBLI robot type TX60 (6 axes) - Robot collet double clamping external type PZN50 - Swiveling plate (4 positions) - Coolant tank KNOLL with hinged chip conveyor, 2 HP pumps 40 [bars] Bedpfx Ajuhantsbcewh - Oil mist aspiration device Büschel - Cooling unit RIEDEL - Preparation ARTIS

Condition: used, TECHNICAL DETAILS - number of spindles : 6 - max. bar diameter : 18 [mm] - slide unit 1.1 : X and Z axes controlled by CNC - slide unit 1.2 : Z axis controlled by CNC - slide unit 2.1 : Z axis controlled by CNC - slide unit 2.2 : X and Z axes controlled by CNC - slide unit 3.1 : X and Z axes controlled by CNC - slide unit 4.1 : X and Z axes controlled by CNC - slide unit 5.1 : X and Z axes controlled by CNC - slide unit 6.1 : X and Z axes controlled by CNC - slide unit 6.3 EQUIPMENT - CNC SIEMENS 840D - Counter spindle - Bar loader IEMCA SIR MS18/33 P - Coolant tank KNOLL * with high-pressure pump - Chip conveyor KNOLL - Parts catcher Bodpfx Abouhan Tjcswh - Ejection of workpiece

Condition: used, TECHNICAL DETAILS - Spindle power : 10,5 [kW] - Spindle speed : 10 000 [Rpm] - Spindle type : A2-4 - Strokes X/Y/Z : 280/280/145 [mm] - Quick movement : 50 [m/min] - Loading zone strokes X/Z : 110/90 [mm] - Tools number : 8 - Motorized tools number : 2 - Rotary tools speed : 6000 [tr/min] - Rotary tools power : 9,5 [kW] - Tools type : Capto C4 - Dimensions : 1700 x 3000 x 2400 [mm] - Weight : 4000 [kg] - Installed power : 2,5 [kW] EQUIPMENT - CN Siemens 840D Bwsdpeuhbftjfx Abcoh - Axis C - Measuring rules on linear axes - Counter spindle - 1 turning tool holder for counter operation - Coolant tank with pump - Chip conveyor

Condition: used, TECHNICAL DETAILS - Number of spindles : 2 - Number of axes : 6 - Number of turrets : 3 MAIN SPINDLE - Spindle power : 29 [kW] - Spindle speeds : 6000 [rpm] - Max. bar diameter : 65 [mm] - C axis indexing precision : 0.001 [°] COUNTER-SPINDLE - Spindle power : 4.2 [kW] - Spindle speeds : 4500 [rpm] - C axis indexing precision : 0.001 [°] - Travel : 280 [mm] UPPER LEFT TURRET - Number of positions : 5 - Tool type : VDI25 UPPER RIGHT TURRET - Number of positions : 8 - Number of motorized positions : 8 - X/Z stroke : 90/280 [mm] - Tool type : VDI25 - Live tools speed : 4500 [rpm] - Live tools power : 4.2 [kW] LOWER LEFT TURRET Bodpfx Asuhac Djbcswh - Number of positions : 6 - X/Z stroke : 81/80 [mm] POWER SUPPLY - Supply voltage : 400 [V] - Total installed power : 35 [kW] EQUIPMENT - CNC : INDEX C200-4 - Coolant tank * with high-pressure pump - Chips conveyor - Parts catcher - Parts conveying strip - Collet chuck