Miller Pro 400x Welder

MAKE: Miller

MODEL: Big Blue® 400x Pro (Kubota) ArcReach®

In Stock and available for shipping

Unrivalled Precision, Power, and Efficiency

Experience unmatched ease, reliability, and fuel economy with the professional-grade Miller Big Blue 400x Pro with ArcReach®. Powered by a heavy-duty Kubota engine, this welder introduces ArcReach® technology, allowing precise weld adjustments right at your fingertips.

Boasting a variety of advanced features, including Adaptive Hot Start™, Infinite arc control, and Auto-Process Select™, this welder truly stands unrivalled in its class.

Miller Pro 400x Specifications

Title: Big Blue® 400 Pro (Kubota) ArcReach®

Industries Interests: Construction and Fabrication, Pipeline

Amperage: 20 A – 400 A

Weldable Metals: Stainless Steel, Steel

Rated Carbon Diameter: 3/16 in (4.8 mm)

Current Type: DC

Max Open Circuit Voltage: 85 VDC

Portability: Lift Eye (Standard) | Trailer (Optional)

Cold Weather Starting Aids: Engine Block Heater, Glow Plugs

Engine Brand: Kubota

Engine Compliance: T4F

Engine Idle Speed: 1500 RPM

Engine Weld Speed: 1800 RPM

Fuel Tank Size: 11.5 Gallons

Fuel Type: Diesel

Horsepower: 20.2 hp

Weld Output: CC / CV

Rated Output: 400 A at 24 V, 100% Duty Cycle,350 A at 27 V, 100% Duty Cycle,300 A at 32 V, 100% Duty Cycle

Single Phase Auxiliary Continuous Power: 10000 W

Single Phase Auxiliary Peak Power: 12000 W

Sound Rating: Idle: 66 dB, Weld: 71.6 dB

Applications: Fabrication, Mobile Fabrication & MRO, Process Pipe, Structural Welding

Net Width: 26.25 in

Net Height: 32 in

Net Length: 56 in

Net Weight: 950 lbs

Warranty: 3 Years Miller’s True Blue Warranty

Miller Pro 400x Features

ArcReach® Technology

Equipped with exclusive ArcReach® technology, this feature allows process adjustments right from your weld cables, placing arc control beneficially at your fingertips. Ideal for both stick and solid wires, ArcReach ensures you’re no longer tied to the power source – a testament to the product’s superior convenience and reliability.

ArcReach Heater Compatibility

Assert control and efficiency in your preheating applications with the 400x Pro’s ArcReach Heater. Capable of reaching up to 600 degrees Fahrenheit (315°C), this system uses induction heating for quick, safe preheating. As part of the ArcReach technology platform, this heater is a beneficial accessory that provides soft tig arc starting.

Auto-Process Select™

Enhance your workflow with the 400x Pro’s Auto-Process Select™. This feature intuitively detects and switches to the correct process based on polarity and the connected ArcReach accessory, reducing the need to manually access the power source.

Advanced Features for the Professional Welder

The 400x Pro’s advanced features, including Adaptive Hot Start™, make starting stick electrodes a breeze. Benefit from infinite arc control in Stick and Wire modes, making arc control beneficial when fine-tuning tough-to-weld materials and out-of-position applications.

The Lift-Arc™ TIG feature minimises contamination risk during arc starting without requiring high frequency.

Control Panel Lock Out

There’s nothing to worry about accidental changes with its Control Panel Lock Out feature. It ensures that while an ArcReach accessory is in control, all process and amperage/voltage adjustments at the power source are securely locked out, preventing any unintentional alterations by non-operating personnel. This feature is your guarantee of absolute reliability and precision in every welding operation.

Dynamic DIG™

Expect a smoother, more consistent arc with Miller’s proprietary Dynamic DIG™. Compared to traditional DIG with preset short-clearing current, Dynamic DIG™ utilises a time-based algorithm to automatically adjust the required current to clear a short. This means you get an adaptable arc that can be customised to match the material, welder technique, application, and fit-up.

Fleet Compatibility

  • Cross Platform Compatible: This ensures that ArcReach accessories used on engine-driven equipment are also compatible with select ArcReach-equipped XMT®, Dimension™, and PipeWorx 350 FieldPro™ power sources.
  • Reverse Compatible: Reverse compatibility guarantees that ArcReach-equipped power sources work efficiently with non-ArcReach accessories, although full benefits are realised with the complete ArcReach system.

Heavy-Duty Low-Speed Kubota V1505 Industrial Diesel Engine

More run hours mean more productivity with the heavy-duty, low-speed Kubota V1505 industrial diesel engine. Trusted in global industrial applications, the V1505 is engineered to provide up to 10,000 hours of operation before major maintenance – backed by world-class service and support.

Increased Productivity & Safety

Complete your projects faster and safer with ArcReach. It significantly increases arc-on time and minimises the risk of trips, slips, and falls. With ArcReach, there’s less need to return to the welding power supply for process adjustments and arc amperage or voltage settings, boosting efficiency and safety.

Industrial USB Port

Conveniently keep your Miller Pro 400x up-to-date and monitor its performance with the industrial USB port. You can download machine log files and perform software updates easily, offering valuable insights into diagnostics and machine statistics.

Other Standard Features

You can also enjoy features like automatic idle, a 120-volt engine block heater, output contactor control, and thermal overload protection, enhancing the Miller Pro 400x’s reliability and efficiency.

Miller Pro 400x Applications

  • Construction
  • Fabrication
  • Maintenance
  • Mechanical contractors
  • Pipe welding
  • Rental
  • Repair
  • Structural steelwork


Miller Pro 400x Processes

  • Air carbon arc (CAC-A)
  • Rated: 3/16-inch (4.8 mm) carbons
  • Capable: 1/4-inch (6.4 mm) carbons
  • Air plasma cutting and gouging with optional Spectrum® models
  • Flux-cored (FCAW)*
  • MIG (GMAW)*
  • Pulsed MIG (GMAW-P)**
  • RMD®**
  • Stick (SMAW)

*With wire feeder

**ArchReach models only with ArcReach Smart Feeder

Miller Pro 400x FAQs

How long will a Miller Pro 400x run?

Engineered for efficiency, this machine operates for extensive periods due to the heavy-duty, low-speed Kubota V1505 industrial diesel engine. It is designed to provide up to 10,000 hours of operation before major maintenance, ensuring uninterrupted productivity for your projects.

What engine is in a Miller Pro 400x?

This dynamic machine is powered by the globally trusted V1505 industrial diesel engine from Kubota. Known for its durability and performance, the Kubota engine enables longer run hours and optimum productivity.

How many amps is a Miller Pro 400x?

Delivering exceptional performance, it offers a broad amperage range from 20 A to 400 A. This wide spectrum ensures flexibility and adaptability for a variety of welding applications, from fabrication jobs to pipeline work.

How much does a Miller Pro 400x weigh?

Balancing power and portability, it weighs in at 950 lbs (431 kg). Despite its sturdy and robust construction, this weight allows for relative ease in transportation, enabling you to bring superior welding performance wherever it’s needed.

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