Okuma LB4000 EX II

$175,000 - $275,000 Updated 2026-03-11

Key Specifications

Max Spindle

4,200 RPM (3,000 or 1,500 RPM options)

Spindle Power

30 kW (40 hp) standard; 22 kW (30 hp) continuous

Max Turn Length

2,150

max turning diameter

480

spindle nose

A2-8

spindle torque

High torque via PREX motor (configuration dependent)

Overview

The Okuma LB4000 EX II is a heavy-duty 2-axis CNC turning center built for shops that need large-bore capacity, high rigidity, and thermal stability in a production lathe. With a maximum machining diameter of 480 mm (18.9 in) and bed lengths from 380 mm to 2,150 mm, the LB4000 EX II handles everything from short chucking work to long shaft machining. The A2-8 spindle nose accepts up to 18.5-inch chucks, and the through-hole bore accommodates large-diameter bar stock.

Okuma's PREX motor delivers 30 kW (40 hp) of spindle power with high torque across the speed range, supporting heavy roughing in steel and cast iron as well as high-speed finishing in aluminum. Spindle speed options range from 1,500 to 4,200 RPM depending on the configuration, letting shops match the spindle to their primary material mix. The slant-bed box construction provides exceptional rigidity, and Okuma's Thermo-Friendly Concept actively compensates for thermal growth to maintain accuracy across long production runs without warm-up cycles.

The OSP-P control is Okuma's open-architecture platform, running both conversational and G-code programming with an intuitive interface. Options include Y-axis travel for off-center machining, live tooling for milling and cross-drilling, and integration with Okuma's ARMROID in-machine robot and Standby APC systems. Competitors include the DMG Mori CLX 550, Mazak QT-300, and Doosan Puma 4100. New LB4000 EX II machines price between $175,000 and $275,000 depending on bed length and options. Used units from 2015-2021 trade between $80,000 and $175,000.

Full Specifications

Parameter	Value
Max Turning Diameter	480
Max Turning Length	2,150
Max Spindle Speed	4,200 RPM (3,000 or 1,500 RPM options)
Spindle Nose	A2-8
Spindle Motor Power	30 kW (40 hp) standard; 22 kW (30 hp) continuous
Spindle Torque	High torque via PREX motor (configuration dependent)
Bar Capacity	Up to 190 mm (7.5 in) with Super Big Bore option
Chuck Size	Up to 18.5 in (470 mm)
Rapid Traverse X	25 m/min (984 ipm)
Rapid Traverse Z	30 m/min (1,181 ipm)
Turret Type	12-station bolt-on (VDI or BMT options available)
Tailstock	Programmable hydraulic tailstock (standard on longer bed models)
Machine Weight	6,500 - 9,000 kg (14,330 - 19,842 lb) depending on bed length
CNC Control	Okuma OSP-P300L / OSP-P500L
Thermal Management	Thermo-Friendly Concept (active thermal compensation)
Speed Range	42~4,200
Rapid Traverse X Z	25/30
Standard Power	30/22
Okuma Global Repair Center	Charlotte, North Carolina
Inches	Metric
Spindle Nose Type	JIS A2-8

Specifications sourced from okuma.com — verified 2026-03-28

Strengths & Limitations

Strengths

Thermo-Friendly Concept actively compensates for thermal growth, delivering consistent accuracy across long production runs without warm-up cycles or mid-shift drift correction
Wide range of bed lengths (380 to 2,150 mm) and bore sizes including the Super Big Bore option at 190 mm means one platform covers short chucking work through long shaft machining
PREX motor delivers high torque across the full speed range, supporting heavy roughing in steel and cast iron without the torque drop-off common in conventional spindle motors
Slant-bed box construction provides exceptional rigidity for interrupted cuts and heavy stock removal, outperforming competitors using lighter frame designs
Open-architecture OSP control runs both conversational and G-code programming, and accepts third-party apps and custom macros without Okuma licensing restrictions
Strong North American dealer and service network with generally lower parts and service costs compared to European OEMs

Limitations

Rapid traverse at 25/30 m/min (X/Z) is slower than some competitors offering 36-40 m/min, which adds non-cutting time on high-volume production runs with frequent repositioning
The OSP control, while powerful, has a steeper learning curve for operators coming from FANUC or Siemens environments and requires Okuma-specific training
Base machine without Y-axis and live tooling is a straightforward 2-axis lathe; adding these options significantly increases cost and lead time
At 6,500-9,000 kg depending on bed length, the machine requires substantial foundation preparation, especially for the longer-bed configurations

Best For

Oil and gas shops turning large-diameter pipe fittings and valve components that benefit from the Super Big Bore through-hole capacity up to 190 mm Production environments running steel and cast iron parts where the PREX motor's high torque and the rigid box-way construction provide maximum metal removal rates Shops requiring thermal stability for tight-tolerance turning over long shifts without operator intervention to compensate for thermal drift Facilities already running Okuma equipment that want fleet standardization on OSP controls and Okuma's Thermo-Friendly platform Contract manufacturers needing a versatile lathe platform that can be configured for short chucking work, long shaft turning, or Y-axis milling in a single machine family

Frequently Asked Questions

01 What does a new Okuma LB4000 EX II cost?

New LB4000 EX II machines start around $175,000 for a base 2-axis configuration with the shortest bed. Adding Y-axis, live tooling, longer bed lengths, Super Big Bore spindle, and automation can push the price to $250,000-$275,000+. Used units from 2015-2021 trade between $80,000 and $175,000 depending on configuration, hours, and options.

02 What is the Thermo-Friendly Concept?

Okuma's Thermo-Friendly Concept is a built-in thermal compensation system that uses sensors and algorithms to predict and correct thermal growth in the spindle, bed, and ballscrews. Unlike external temperature compensation that reacts to measured drift, Thermo-Friendly proactively adjusts positioning before errors occur. This eliminates the need for warm-up cycles and maintains accuracy across ambient temperature changes and varying cutting loads.

03 What bed length should I choose?

The LB4000 EX II is available in 380, 750, 1,500, and 2,150 mm turning lengths. The 750 mm is the most popular general-purpose option. Choose 380 mm for pure chucking work, 1,500 mm for shaft work with tailstock support, and 2,150 mm for long shafts and bar stock. Longer beds add cost and floor space, so match the bed to your longest common part plus fixture allowance.

04 How does the LB4000 EX II compare to the LB3000 EX II?

The LB4000 EX II is the larger sibling with a 480 mm max turning diameter versus 340 mm on the LB3000 EX II. It accepts larger chucks (up to 18.5 in vs 12 in), has more spindle power (30 kW vs 22 kW), and offers the Super Big Bore option for large bar stock. The LB3000 EX II is more compact, faster in rapids, and better suited for smaller parts and higher-speed production.

05 Can I add milling capability to the LB4000 EX II?

Yes. The MY configuration adds a Y-axis and live tooling to enable milling, drilling, and tapping operations without moving parts to a separate machining center. The Y-axis provides off-center reach for cross-drilling and contouring. This adds cost but reduces total cycle time and eliminates part handling between machines for parts that need both turning and milling features.

06 What automation options are available?

Okuma offers the ARMROID in-machine robot for part loading/unloading, the Standby APC for automatic pallet changing on chuck work, and standard interfaces for bar feeders and gantry loaders. The open-architecture OSP control also supports third-party automation integration. For bar work, LNS and IEMCA feeders are commonly paired with the LB4000 EX II.