Okuma VTR-350A

$1,000,000 - $2,500,000 Updated 2026-03-13

Key Specifications

Max Spindle

min⁻¹ (rpm)

Tool Capacity

23 tools

Table Size

Ø3,000

Spindle Power

55/45

Max Turn Length

1,600 [2,000; 2,400]

max turning diameter

Ø137.79

Overview

The Okuma VTR-350A is a heavy-duty vertical turning and milling center built for machining the largest round workpieces, handling parts up to 3,500 mm (137.8 in) in diameter and 1,600 mm (63.0 in) in height. This machine serves the upper end of the vertical turning spectrum where workpiece size, weight, and the need for multitasking capability converge in industries like power generation, marine, oil and gas, and heavy aerospace.

The main table rotates at up to 160 RPM, driven by a 55 kW (75 hp) motor at 30-minute rating and 45 kW (60 hp) continuous. While 160 RPM may seem modest, at a 3,500 mm diameter the table periphery is already moving at over 1,750 m/min — well beyond the surface speed range for most steel and alloy turning operations. The milling spindle adds drilling, tapping, and contour milling capability to eliminate secondary machining center setups on large workpieces.

Tool storage accommodates 23 tools. Machine dimensions are 8,615 x 5,374 x 6,300 mm, reflecting the massive scale of the machine. The VTR-350A runs on Okuma's OSP control with Thermo-Friendly Concept, which is particularly critical on large vertical lathes where thermal growth proportional to machine size can cause significant dimensional errors across long machining cycles.

The VTR-350A competes with the Hankook VTB series, Toshulin POWERTURN, and Berthiez TVU series in the large VTL segment. Okuma's advantage is the integrated CNC control and Thermo-Friendly Concept, which many competing large VTL manufacturers do not match. New VTR-350A machines typically price in the $1,000,000 to $2,500,000 range depending on configuration. The machine is purpose-built for marine diesel engine components, large turbine casings, nuclear reactor vessel flanges, and mining equipment components. Specs sourced from Okuma Corporation published data.

Full Specifications

Parameter	Value
Max Turning Diameter	Ø137.79
Max Workpiece Height	1,600 mm (63.0 in)
Table Speed Max	160 RPM
Main Motor Power	55/45 kW (30 min/continuous) (75/60 hp)
Tool Capacity	23 tools
Machining Type	Turning + Milling (multitasking)
CNC Control	Okuma OSP-P500M
Machine Dimensions	8,615 x 5,374 x 6,300 mm (339.2 x 211.6 x 248.0 in) (W x D x H)
Thermo Friendly Concept	Standard
Anti Crash System	Standard
Process Navi	Standard
Servo Navi	Standard
Workpiece Shape	Large round/cylindrical parts, turbine casings, flanges, rings
Table Surface Speed At Max Dia	~1,759 m/min at ø3,500 mm and 160 RPM
Max Turning Length	1,600 [2,000; 2,400]
Z Axis Travel Ram	1,250 [1,500]
W Axis Elevating Rail	800 [1,000; 1,200]
Table Size	Ø3,000
Max Load	20,000
Max Spindle Speed	min⁻¹ (rpm)
Spindle Motor Power	55/45
Torque	42.5/34.8 [58.0/46.4]
Swing Max Turn	Ø3,500
Okuma Global Repair Center	Charlotte, North Carolina
Inches	Metric
Spindle Speed	1~160
C Axis	360 (minimum control angle: 0.001)

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

Strengths & Limitations

Strengths

3,500 mm maximum turning diameter handles the largest round workpieces in power generation, marine, and heavy industry without specialized floor-type lathes
55 kW motor provides the power needed for heavy roughing operations on large steel, cast iron, and alloy workpieces
Combined turning and milling capability eliminates transferring multi-ton workpieces between a VTL and machining center, saving hours of crane and setup time
Thermo-Friendly Concept is critical at this machine scale where thermal growth can cause millimeter-level errors over long machining cycles
Okuma's single-source control integration provides reliability and serviceability advantages over large VTLs from manufacturers using third-party CNCs
Vertical orientation simplifies workpiece loading with overhead cranes and provides natural chip evacuation by gravity

Limitations

23-tool magazine is very limited for a machine of this capability — complex multitasking operations will require manual tool management
160 RPM maximum speed limits surface speed on smaller-diameter features, though full-diameter operations are well within productive speed ranges
Machine footprint of 8,615 x 5,374 mm plus service clearances requires a dedicated bay with substantial overhead crane capacity
Foundation requirements for a machine of this size and the heavy workpieces it handles add significant installation cost
Premium pricing starting at $1,000,000+ limits this machine to shops with consistent large-part production volume

Best For

Power generation manufacturers machining large turbine casings, generator housings, and reactor vessel components Marine industry shops producing propeller hubs, large flanges, and marine diesel engine components Oil and gas manufacturers machining blowout preventer bodies, large valve housings, and subsea equipment components Mining and heavy equipment manufacturers producing large bearing housings, gear rings, and crusher components Nuclear industry contractors machining reactor components and pressure vessel flanges requiring multitasking capability Aerospace manufacturers machining large engine casings and rocket motor components

Frequently Asked Questions

01 What does a new Okuma VTR-350A cost?

New VTR-350A machines typically price between $1,000,000 and $2,500,000 depending on milling spindle configuration, live tooling options, and accessories. The large scale of the machine means options like high-pressure coolant, probing, and enhanced chip management add proportionally more cost. Used VTR-350A machines are rare on the secondary market due to the specialized nature of the applications.

02 What workpiece weight can the VTR-350A handle?

The VTR-350A is designed for extremely heavy workpieces typical of the 3,500 mm diameter class. Parts in the 5,000-20,000 kg range are common applications. The specific maximum weight depends on part geometry, balance, and fixture configuration. Consult Okuma directly for your specific application requirements, as the machine and foundation must be specified together for very heavy workpieces.

03 How does the VTR-350A compare to a conventional VTL?

The VTR-350A adds CNC milling capability to vertical turning, eliminating the need to transfer heavy parts to a separate machining center for cross-drilled holes, bolt patterns, and milled features. Traditional VTLs in this size class are turning-only and require secondary operations. The trade-off is higher acquisition cost, but the time savings from single-setup machining often justify the investment for parts requiring both turning and milling.

04 Is 160 RPM fast enough for productive turning?

At 3,500 mm diameter, 160 RPM produces a surface speed of approximately 1,759 m/min, which far exceeds typical cutting speeds for steel and cast iron (150-250 m/min). The machine reaches productive cutting speeds even at relatively low RPM due to the large diameter. For smaller diameter features (e.g., 500 mm bore), the surface speed at 160 RPM drops to about 251 m/min, which is still productive for steel turning with carbide tooling.