Schaublin 53 N pirkti naudotą (50)

Sąlyga: naudotas, Working Area Centre Height: 102 mm Centre Distance: - with standard headstock: 450 mm - with reduction gear headstock: 375 mm - over bed: 200 mm - over cross-slide: 120 mm Headstocks Spindle nose for collets type Schaublin W25 Spindle bore: 25 mm Collet through-hole: 20 mm Reduction gear ratio: 1:5 Bed Height x width x length: 168 x 130 x 1000 mm Cpedpfx Asbxkl Tof Tou Bed made of cast iron, trapezoidal profile as on lathe 102 N, hardened and ground dovetail guideways. Slides Maximum travel on bed: 400 mm Tool slide width – length: 80 – 194 mm Manual adjustment travel: 90 mm Centre height over tool slide: 20 mm Tool holder shank: 12 x 12 mm Cross-slide width – length: 94 – 300 mm Manual adjustment travel: 100 mm Saddle guide length on the bed: 250 mm Leadscrew Leadscrew for longitudinal turning and thread cutting, Ø 40 mm Leadscrew hardened, thread ground, pitch 4 mm Speed Range Spindle speed: 270 – 3000 rpm Longitudinal feed: 0.02 – 0.3 mm/rev Thread Cutting Maximum pitch with standard change gear set: 4 mm Machine plate for 20 metric pitches: 0.25 – 4 mm Machine plate for 25 imperial pitches: 80 – 6 TPI Tailstock Quill diameter: 30 mm Quill taper: 2 Morse Quill travel: 80 mm Coolant Equipment Coolant tank capacity: 23 litres Net Weights Lathe on workbench, approx. 225 kg Lathe on cabinet base, approx. 550 kg

Sąlyga: naudotas, Techniniai duomenys: X eiga: 700 mm Cpsdpsxtnn Tjfx Af Tsu Sūkiai: iki 1500 aps./min Pavaros greitis: 12 - 1000 mm/min Stalo matmenys: 1100 x 250 mm Galva pasukama: taip Matmenys, apytiksliai: 1750 x 1600 x 1850 mm Svoris, apytiksliai: 1900 kg

Sąlyga: naudotas, bendras aukštis: 1 700 mm, bendras plotis: 1 600 mm, bendras ilgis: 1 800 mm, Savaiminis svoris: 1.650 kg Cpodpfxjwni Ako Af Tou - Dokumentacija prieinama: Taip - CE sertifikatas: Ne - Valdymas: Konvencinis - Galia [kW]: 4,0 - Ašių skaičius [vnt.]: 3 - X ašies eiga [mm]: 700 - Y ašies eiga [mm]: 550 - Z ašies eiga [mm]: 430 - Stalo ilgis [mm]: 1100 - Stalo plotis [mm]: 255 - Įrankio tvirtinimas: ISO30 - Min. veleno sūkių skaičius [aps./min.]: 38 - Maks. veleno sūkių skaičius [aps./min.]: 1500 - Papildomos parinktys: Skaitmeninis indikatorius - Skaitmeninio indikatoriaus tipas: Sony - Transportavimo matmenys: 1800mm x 1600mm x 1700mm (i x p x a) - Transportavimo svoris [kg]: 1650kg - Transporto pakuotės [vnt.]: 1 Finansinė informacija PVM: Nurodyta kaina be PVM PVM / skirtumo apmokestinimas: PVM atskaitomas įmonėms Pristatymas ir priėmimas į keitimą galimi bet kuriuo metu viskam iš pramonės sektoriaus Lukas van Rossum

Sąlyga: paruoštas naudoti (naudotas), Table clamping surface: 1100 x 255 mm Table travel x-axis: 700 mm Table travel y-axis: 250 mm Table travel z-axis: 430 mm Spindle speeds: 38 - 1500 rpm Codpfjv Dh Irsx Af Topu Feeds longitudinal and cross: 12 - 1000 mm/min Vertical feed: 1.75 m/min Electrical connection: 380 V, approx. 4 kW Required space: 1700 x 1600 x 1650 mm Weight: 1650 kg

Sąlyga: naudotas, TECHNINIAI DUOMENYS - Viršūnės aukštis: 102 [mm] - Didž. skersmuo virš lovos: 200 [mm] - Atstumas tarp viršūnių: 470 [mm] - Ašies laikiklio tipas: W20 Csdpfx Asw Ihttsf Tjpu - Skylė: 20 [mm] - Perėjimas nuo strypo prie įvorės: 14,5 [mm] SVORIS IR IŠMATAVIMAI - Užimamas plotas: 1500 x 800 [mm] - Staklių aukštis: 1300 [mm] - Staklių svoris: 500 [kg]

Sąlyga: naudotas, Didžiausias tekinimo skersmuo virš staklių lovos: 310 mm Didžiausias tekinimo skersmuo virš skersinio: 160 mm Valdymas: BOSCH CNC ALPHA 2 Centru atstumas: 340 mm Centro aukštis: 148 mm Špindelio apsisukimai: 3.000 aps./min X ašis: 220 mm Cedpfx Aew Sx Ucof Tjpu Z ašis: 400 mm Mūsų vertinimu, staklės yra geros naudotos būklės, jas galima apžiūrėti įjungtas pagal susitarimą. Priedai, paveikslėliuose matomi įrankiai ir tvirtinimo elementai į pristatymo komplektą įtraukiami tik tuo atveju, jei tai nurodyta papildomoje informacijoje. Techniniai duomenys ir pateikta informacija gali keistis arba būti netikslūs, taip pat galimas tarpinis pardavimas!

Sąlyga: naudotas, Schaublin 102-N80 Šveicariškas precizinis tekinimo staklės Techninės specifikacijos: Centro aukštis: 102 mm Atstumas tarp centrų: 450 mm Veleno kiaurymė: 32 mm reduktorius kairės / dešinės eigos 2 pakopų pavara Vario greitis: 270-3000 aps./min knee circuit Tekėjimo skersmuo virš staklių: 200 mm Veleno antgalis: W20 Galinė atrama: MK 2 Matmenys (IxPxA): apie 140x56x123 cm Svoris: apie 550 kg Priedai / pasirinkimai: - 3 žandikaulių griebtuvas su žandikauliais - 4 žandikaulių griebtuvas su žandikauliais - Įrankių laikikliai - Schaublin įvorės nuo 0,5 mm Cpedpexxavgefx Af Tsu Po įtampa mūsų sandėlyje.

Sąlyga: paruoštas naudoti (naudotas), Gamybos metai: 2008, veleno greitis (maks.): 5 000 aps./min, bendras aukštis: 1 840 mm, bendras svoris: 3 040 kg, valdiklių gamintojas: FANUC, valdiklio modelis: 18i-TB, ašių skaičius: 4, Šios 4 ašių "Schaublin 140R" CNC horizontalios tekinimo staklės pagamintos 2008 m. Staklės turi CNC "Fanuc 18i-TB" valdymą, maksimalų 300 mm tekinimo skersmenį ir 50-5 000 apsukų per minutę suklio sukimosi dažnį. Joje įrengta Y ašis ir papildomas suklys, revolveris su 12 varomųjų įrankių stočių. Jei ieškote aukštos kokybės tekinimo galimybių, apsvarstykite mūsų parduodamas "Schaublin 140R CNC" stakles. Susisiekite su mumis ir gaukite daugiau informacijos. Papildoma įranga • Įrenginys tiekiamas su instrukcijomis ir CE atitikties deklaracija Mašinos privalumai Techninės mašinos privalumai Cedpfx Aeyalqgjf Tspu • Varomų įrankių stotys: 12 • Maksimalus įrankio dydis: 20 x 20 mm • Varomojo įrankio greitis: 30–6000 aps. /min. • Uodegos atrama a2-3 • Galimybė montuoti 3 žandikaulių griebtuvą: taip • Rekomenduojamas maksimalus tekinimo skersmuo: 200 mm • Aušinimo skysčio sistema: bako talpa 180 l, siurblio našumas 20 l/min, siurblio slėgis 6 bar • Maks. Tekinimo skersmuo: 300 mm • Rekomenduojamas maksimalus tekinimo skersmuo: 250 mm • Įrengta y ašimi ir subvelenu Papildoma informacija Mašina vis dar įjungta Dimensions Machine Depth 2650 mm

Sąlyga: labai geros būklės (naudotas), Funkcionalumas: visiškai funkcionalus, High-Precision Lead Screw Lathe Schaublin 102N-VM Technical Data: >> Machine No.: 283152 >> Centre Height: 102 mm >> Distance Between Centres: 450 mm Cpodswvq Tmspfx Af Tsu >> Spindle Bore: 25 mm >> Longitudinal Feeds: 8 settings from 0.02–0.3 mm/rev >> Metric Threads: 20 pitches from 0.25 to 4 mm >> Imperial Threads: 25 pitches from 80 to 6 TPI >> Tailstock: Morse Taper 2 (MT2) >> Infinitely Variable Speed Range: 270–3000 rpm >> Weight: approx. 700 kg Accessories: >> 3-jaw chuck with 2 sets of jaws >> Tool holder with 6 tool pockets >> Quick collet closer, draw tube, and 34 collets >> Coolant system >> Cutting tools, drill chuck (see photos) >> Operating manual with spare parts list About the Machine: For sale is a Schaublin 102VM lead screw lathe in very good condition. The machine is, of course, fully functional. All slides run smoothly and evenly. Even at high speeds, the 102VM runs quietly. The gear set for thread cutting is included, although it may not be complete. Take advantage of the opportunity to inspect this machine under power on site and see its excellent condition for yourself.

Sąlyga: labai geros būklės (naudotas), Gamybos metai: 2005, Schaublin 102N-VM-CF hochpräzisions-Drehmaschine aus Schweizer Fertigung Baujahr: 2005 Max. zulässiger Umlaufdurchmesser über Bett: 200 mm Max. zulässiger Umlaufdurchmesser über Support: 120 mm Spitzenhöhe: 102 mm Cpedpfow N Rh Aex Af Teu Spitzenweite: 450 mm Bettlänge: 1000 mm Betthöhe: 168 mm Motorleistung: 4,2 kW Spindeldrehzahl: 100 - 3000 U/min Spindelaufnahme: W25 Querweg X-Achse: 100 mm Auflösung X-Achse (Radius): 0,01 mm Längsweg Z-Achse: 90 mm Auflösung Z-Achse (Radius): 0,01 mm Leitspindel: - 8 Längsvorschübe - Größere Vorschübe möglich bei Nutzung der Gewindesteuerung zum Drehen Maximaler Werkzeugquerschnitt (Multifix-System): 10x10 mm Stangenspanner (Multifix-System), Durchmesser: 20 mm Höhen- und seiteneinstellbarer Reitstock: Innenkonus Hülse: MK2 Reitstockdorn-Ø: 30 mm Reitstockweg: 80 mm Kühlmitteltank: 23 Liter Elektr. Anschlusswert: 400 V Abmessungen (L x B x H): 1500 x 510 x 1550 mm Zubehör / Optionen: - ACU-RITE Digitalanzeige, 3-Achsen (X-Z-Z1): X-Auflösung 0,001 mm Z-Auflösung 0,005 mm Z1-Auflösung 0,005 mm - Kühlmittelanlage - Rückseitige Blechverkleidung - Doppeltes Start/Stopp-Pedal mit Spindelumkehr - Schaublin W25 Spannzangensatz - Gussfutter W25 Ø110 mm mit Backen - Multifix-A Schnellwechselrevolver mit Haltern - Antriebssystem für Zusatzaggregate mit Riemen, verstell- und schwenkbare Riemenspannvorrichtung, kompletter Antrieb mit Motor, Riemen Ø6x2.500 mm - Reitstock - usw. Unter Strom in unserem Lager verfügbar.

Sąlyga: visiškai atnaujintas (naudotas), Gamybos metai: 2002, veikimo valandos: 2 500 h, Funkcionalumas: visiškai funkcionalus, mašinos/transporto priemonės numeris: 350523, Įranga: CE žymėjimas, Voltage: 380V Net weight: 1,400 kg Customs tariff number: 8458.1120 Dimensions: 180 x 128 x 172 cm TECHNICAL SPECIFICATIONS CAPACITIES Maximum turning diameter: 270 mm Maximum diameter over cross slide: 115 mm Center height over cross slide: 60 mm Turning length B32: 265 mm Center height above floor: 1,162 mm HEADSTOCK A2-4 / Camlock D1-3’’ Spindle for collets Schaublin Hainbuch / F38 / B32 Spindle speed: 50 – 5,000 rpm AC motor drive – continuous/intermittent power: 5.5 / 7.5 kW AC motor drive – continuous/intermittent torque: 42 / 58 Nm Spindle bore (without clamping key): 39 mm Maximum bar capacity with collet: 32 mm Maximum bar capacity with automatic chuck: 32 mm PNEUMATIC CLAMPING Adjustable axial clamping force, force at 5 bar: 1,150 daN CROSS SLIDE Transverse travel, X-axis: 190 mm Resolution, X-axis (radial): 0.0005 mm AC motor drive – continuous/intermittent torque: 4 / 14 Nm Ball screw, Ø x pitch: Ø 20 x 5 mm Longitudinal travel, Z-axis: 390 mm Resolution, Z-axis: 0.001 mm AC motor drive – continuous/intermittent torque: 4 / 14 Nm Ball screw, Ø x pitch: Ø 32 x 5 mm FEEDS Working feed, X and Z axes, stepless: 0 – 5 m/min Rapid traverse, X and Z axes: 8 m/min REVOLVER TOOL SYSTEM Standard tool holder interface: VDI 20 Number of fixed/rotating tool stations: 8 / - Max. tool size: 16 x 16 mm Integrated coolant supply and bi-directional indexing: Yes COOLANT Tank capacity: 55 L Pump capacity: 10 L/min Pump pressure: 1.7 bar PNEUMATIC TAILSTOCK Quill taper: MT3 Quill outer diameter: 45 mm Quill stroke: 70 mm Adjustable thrust force: 25 – 260 daN All technical data is provided without obligation and subject to errors or omissions. Codpfx Aox Upugof Tepu Fully overhauled: Mechanics, geometry, hydraulics, and electrical parts (checked and/or replaced) Headstock: Disassembled, cleaned, worn and defective parts replaced, bearings replaced, belts replaced, spindle disassembled, seals and O-rings replaced and adjusted. New paint. Turret: Disassembled, cleaned, worn and defective parts replaced, newly painted, and mating surfaces skimmed. Tailstock: Disassembled, inspected, and overhauled. Newly painted. Hydraulics and pneumatics: Disassembled, motor checked, hoses and worn/defective parts replaced. X-axis: Disassembled, worn parts such as O-rings, seals, gaskets replaced. New ball screw and carriage installed. Z-axis: Disassembled, worn parts such as O-rings, seals, gaskets replaced. New ball screw and carriage installed. Electrical cabinet: Completely checked, various relays replaced. Paint: Colors: White RAL 9003 and Grey RAL 7011 Geometry in accordance with manufacturer's protocol. Various accessories checked and cleaned. Year: 2002

Sąlyga: visiškai atnaujintas (naudotas), Gamybos metai: 2026, Funkcionalumas: visiškai funkcionalus, mašinos/transporto priemonės numeris: 310435, Completely overhauled – new paintwork, New workbench Country of manufacture: Switzerland Voltage: 380V, 50Hz, 3Ph Customs code: 8458.1930 TECHNICAL DATA - Centre height: 102 mm - Centre distance, headstock type W, standard: 470 mm - Centre distance, headstock W with reduction gearbox: 375 mm - Swing over bed: 200 mm - Swing over cross-slide: 120 mm Bed: - Height-width-length: 168-100-1000 mm Cast iron bed with ground trapezoidal profile Headstocks: - Spindle nose for collets: W-25 - Collet through-hole: 19.0 mm - Reduction ratio of gear drives: 1:5 Cross slide: - Longitudinal travel: 90 mm - Cross travel: 100 mm - Tool shank cross-section: 12x12 mm Tailstocks: - Quill taper: Morse 2 - Quill travel (tailstock with leadscrew and handwheel): 80 mm Errors or omissions excepted Technical data are provided without obligation Inventory no. 2250006, machine consisting of: 1 NEW workbench 2000x800 mm with blue Urphen slab 2000x800x50 mm Cedpfx Afedr R Tcj Tspu 1 base, 1 cabinet B750 with 7 drawers 1xD50/2xD75/2xD100/1xD150/1xD200 1 bed drive from above 1 workpiece headstock W-20 without gear drive and overhauled clamping key 1 overhauled cross-slide 1 overhauled, aligned tailstock 1 motor 380V/50Hz/3ph, 2 speeds 1 set of W-20 collets 1 3-jaw chuck Ø 100 mm on W-20 flange 1 new set of Multifix toolholders consisting of: - 1 turret A with bolt AG20 - 3 toolholders AD1675 - 1 bar toolholder AH2085 1 self-tightening drill chuck capacity 1-13 mm on Morse taper 2 1 live centre MK2 OPTIONAL 1 used clamping device with new belt CHF 500.-- + VAT 1 GRINDING MACHINE TYPE B-8 with 360° swiveling spindle, max. speed 28,000 rpm, height adjustable, with fine adjustment, Ref. 800053 CHF 1,325.-- + VAT.

Sąlyga: naudotas, Gamybos metai: 1999, veikimo valandos: 17 282 h, Funkcionalumas: visiškai funkcionalus, mašinos/transporto priemonės numeris: 341671, Parduodamas Schaublin 180-CCN Codjyb Rwnopfx Af Tepu

Sąlyga: geras (naudotas), Gamybos metai: 1997, sukimosi skersmuo virš skersinio stumduko: 60 mm, veleno skylė: 24 mm, ašies variklio galia: 7 500 W, sukimosi greitis (min.): 30 aps./min, sukimosi greitis (maks.): 5 000 aps./min, bendras aukštis: 1 660 mm, bendras ilgis: 1 700 mm, bendras plotis: 1 240 mm, bendras svoris: 1 420 kg, CNC tekinimo staklės su spaustuvo patronu F38 Cpsdpfx Aovu Tvpjf Tou Didžiausias tekinimo skersmuo Ø 200 mm, eigų ilgiai X/Z 180/255 mm, įrankių bokštelis SAUTER 8 pozicijų VDI20 (16x16 mm), velenas 7,5 kW, veleno galas A2-4, sūkių diapazonas 30-5000 aps./min., strypo pravedimas Ø 32 mm, tuščiaviduris veleno atmušas, valdymas FANUC Series T-20, vadovai

Sąlyga: labai geros būklės (naudotas), Gamybos metai: 1997, Fanuc Series 20-T control Turning diameter: 330 mm Bar diameter: 42 mm Codowh U Dtjpfx Af Topu Turning length: 650 mm Spindle speed: 5,000 rpm 8-position turret Minimum quantity lubrication

Sąlyga: visiškai atnaujintas (naudotas), Gamybos metai: 2000, Funkcionalumas: visiškai funkcionalus, mašinos/transporto priemonės numeris: 341966, Country of manufacture: Switzerland Voltage: 400/50/3 Net weight: 2640 kg Customs tariff position: 8458.1120 Dimensions: 2301 x 1438 x 1676 mm TECHNICAL SPECIFICATIONS Capacities: Max. turning diameter: 330 mm Max. diameter over cross slide: 160 mm Center height over cross slide: 83 mm Max. diameter over bed: 430 mm Turning length (depending on equipment): 650 mm Headstock: Standardized spindle nose, allowing use of various collets and chucks via adaptation accessories. Accessories for SCHAUBLIN collets: B45/F48 Max. bar capacity dia.: 36 mm/42 mm Automatic chuck, standard dia.: 170 mm Direct drive with AC motor, power at 100%/50% ED: 15/18.5 kW Max. torque at 100%/50% ED: 135/165 Nm Max. spindle speed: 5000 rpm C-Axis: Pneumatic clamping cylinder: 2700 daN Cross Slide: Transverse travel, X-axis: 240 mm Radial resolution: 0.0005 mm Driven by AC motor, nominal torque: 3 Nm Ball screw, X dia. x pitch: 32 x 5 mm Longitudinal travel, Z-axis: 720 mm Resolution: 0.001 mm Driven by AC motor, nominal torque: 6 Nm Ball screw, dia. x pitch: 32 x 10 mm Cpsdpfew T Smhex Af Teu Feeds: Working feed, X/Z axes, stepless: 0-5000 mm/min Rapid traverses, X/Z axes: 8/10 m/min Feed force, X/Z axes: 420/670 daN Turret tooling system: Number of tool stations: 8 Standardized tool holder interface: VDI 30 Max. tool shank section: 20 x 20 mm Integrated coolant supply Bidirectional indexing Coolant system: Tank capacity: 120 liters Pump flow rate: 10 l/min Pressure: 5 bar Except for errors or omissions, the technical specifications are provided without commitment.

Sąlyga: geras (naudotas), Swing diameter over bed: 270 mm Cedpfx Aotwpyasf Tspu Center height: 125 mm Distance between centers: 600 mm Spindle speeds: 30-5000 rpm Control: FANUC 18i Manual Guide Various accessories MARCELS MASCHINEN CH

Gamybos metai: 1998, Sąlyga: paruoštas naudoti (naudotas), Connected load: 24 kW. Cpedpfx Afong E Tyj Tju

Sąlyga: naudotas, Centre height 102 mm Cpedpfx Afjwbi Hpe Teu Centre distance 450 mm Spindle bore 25 mm Spindle speed: 220 - 2600 Accessories have not been checked for completeness Cabinets are not included in the scope of delivery.

Sąlyga: geras (naudotas), Centre height: 102 mm Distance between centres: 450 mm Spindle bore: 32 mm Reduction gearbox Csdjcpznhopfx Af Topu Left/right rotation 2-speed drive Variable speed: 270–3000 rpm Knee lever operation Swing over bed: 200 mm Spindle nose: W 20 Tailstock quill: MK 2 Dimensions (LxWxH): approx. 140x56x123 cm Weight: approx. 550 kg Accessories available Manual available Various 'Schaublin 102' models in stock!

Sąlyga: geras (naudotas), Center height: 130 mm Center distance: 450 mm Speed: approx. 55–3000 rpm Pneumatic clamping system Spindle nose: W 25 Csdpfxecuhvuo Af Topu Various W25 collets available Various holders available BERGER LAHR axis motors Combitec EIP E-500 control unit Manual for control included Coolant system included Machine lamp included Machine feet included Dimensions (LxWxH): approx. 1400x560x1230 mm Weight: approx. 550 kg Various versions of "Schaublin 102" in stock!

Sąlyga: naudotas, TECHNICAL DATA - Max. swing over bed: 270 mm - Max. swing over cross slide: 130 mm - Distance between centers: 440 mm - Spindle nose: CAMLOCK D1-3' - Max. bar diameter: 28 mm - Power: 7.5 kW - Spindle speed: 0–5000 rpm with variator - Travel (X x Z): 180 x 400 mm - Feed rates: 0–5000 mm/min with variator - Rapid traverse: 7500 mm/min - Power supply: 3-phase 380V 50Hz, 14 kW - Dimensions: 1700 x 1226 x 1660 mm - Weight: 1415 kg EQUIPMENT/ACCESSORIES - FANUC 20-T CNC controller - Multifix 'A' quick-change tool turret - SCHAUBLIN B32 collet chuck - Tailstock with handwheel Cpedpfjuhcarex Af Teu - Coolant tank with pump

Sąlyga: naudotas, Centre height 125 mm Centre distance 500 mm Csdpfx Afobzlglj Tspu Spindle speed 45 - 3000 rpm Feed rate 4 – 260 mm/min Spindle nose Camlock D1-3" Tailstock taper MT 2 Swing diameter over bed 250 mm Swing diameter over cross slide 120 mm Top slide travel 100 mm Cross slide travel 180 mm Dimensions (W x D x H) 1500 x 850 x 1300 mm Weight approx. 950 kg

Sąlyga: labai geros būklės (naudotas), - Multifix “B” quick-change tool post - Quick-action collet chuck device Centre height: 150 mm Centre distance: 630 mm Spindle bore: 40 mm Csdpfxjhmkh Te Af Tepu Spindle speed (stepless): 55 – 3000 rpm Feed rate: 0.05 – 0.35 mm/rev Spindle / tailstock taper: MT 5 / MT 3 Swing over cross slide: 177 mm Swing over bed: 340 mm Power: 4.45 kW Dimensions: 1730 x 970 x 1300 mm Weight: 1250 kg

Sąlyga: labai geros būklės (naudotas), Centre height: 125 mm Centre distance: 500 mm Speed range: 45 – 3000 rpm Feed rate: 4 – 260 mm/min Spindle nose: Camlock D1-3" Tailstock taper: MK 2 Swing over bed: 250 mm Swing over cross slide: 120 mm Cpodstzxh Tjpfx Af Tsu Top slide travel: 100 mm Cross slide travel: 180 mm Dimensions (W x D x H): 1500 x 850 x 1300 mm Weight approx.: 950 kg