Okuma MULTUS B550

Est. $700,000 - $1,000,000 Updated 2026-08-10

Key Specifications

Tool Capacity

40 tools

Rapid Traverse

40/40/40 m/min (1,574/1,574/1,574 ipm)

standard chuck size

15 in

max machining diameter

830 mm (32.68 in)

max work length

2,000 / 3,000 mm (78.74 / 118.11 in)

spindle speed

30~3,000 min⁻¹

Overview

The Okuma MULTUS B550 is a large horizontal multi-tasking machine: a 15-inch-chuck turning centre with a milling spindle, on a bed offering either 2,000 mm or 3,000 mm (78.74 or 118.11 in) of maximum work length. Maximum machining diameter is 830 mm (32.68 in), which puts it beyond general-purpose mill-turn territory and into large flange, casing and rotor work.

The main spindle sits on an A2-11 nose — the size that goes with a 15-inch chuck and heavy workholding — and runs from 30 to 3,000 min⁻¹ from a 37/30 kW (50/40 hp) motor rated at 30 minutes and continuous. The shape of that rating defines the machine: 30 kW available indefinitely, and a floor of 30 min⁻¹ for slow boring, threading and facing at large diameters, where a normal cutting speed is reached without much rotational speed at all. Production planning should use the continuous figure; the 37 kW rating covers roughing bursts.

Rapid traverse is 40 m/min (1,574 ipm) on all axes. On a machine with up to three metres of work length that uniform rate matters, because a large share of a long part's cycle is spent traversing between features rather than cutting.

Tool capacity is 40. For a machine intended to turn, mill, drill and bore a large part complete in a single setup, forty pockets is a working library rather than a generous one, and it is worth mapping a representative job against it before ordering.

The W specification adds a second spindle for finishing the back end of a part in-cycle. On components two or three metres long that removes a re-fixture which would otherwise involve a crane, an operator and a fresh datum — the point at which most of the accumulated error on parts of this size gets introduced.

Footprint is 8,030 × 3,258 × 3,307 mm (316.14 × 128.27 × 130.20 in) for the 2,000 mm bed and 9,130 mm long for the 3,000 mm version. Either version needs a bay of its own with crane access along the full length. The machine belongs in oil and gas, power generation and heavy industrial shops where large shafts, valve bodies and casings currently pass through a big lathe and then a boring mill.

Full Specifications

Parameter	Value
Standard Chuck Size	15 in
Max Machining Diameter	830 mm (32.68 in)
Max Work Length	2,000 / 3,000 mm (78.74 / 118.11 in)
Spindle Speed	30~3,000 min⁻¹
Spindle Nose	A2-11
Spindle Motor	37/30 kW (50/40 hp), 30 min/cont
Rapid Traverse Rate	40/40/40 m/min (1,574/1,574/1,574 ipm)
Tool Capacity	40 tools
Machine Dimensions	8,030 × 3,258 × 3,307 mm (316.14 × 128.27 × 130.20 in); 9,130 × 3,258 × 3,307 mm (359.45 × 128.27 × 130.20 in)
Spec Extension	W (second-spindle specification)

Specifications sourced from okuma.co.jp — verified 2026-08-09

Strengths & Limitations

Strengths

830 mm (32.68 in) maximum machining diameter on a 15-inch chuck puts this past general-purpose mill-turn territory and into large flange, casing and rotor work
Bed options of 2,000 mm or 3,000 mm (78.74 or 118.11 in) maximum work length reach genuinely long components
The A2-11 spindle nose is the size that goes with a 15-inch chuck and heavy workholding
A 37/30 kW (50/40 hp) spindle with a 30 min⁻¹ floor allows slow boring, threading and facing at large diameters under full load
Rapid traverse is a uniform 40 m/min (1,574 ipm) on all axes, which matters where a large share of a long part's cycle is spent traversing between features
The W specification adds a second spindle, so the back end of a two- or three-metre part is finished in-cycle rather than through a crane, an operator and a fresh datum

Limitations

Spindle speed tops out at 3,000 min⁻¹, sized for large diameters - smaller-diameter features will not reach productive surface speeds
The motor is rated 37/30 kW at 30 minutes and continuous; plan production against the 30 kW figure and treat 37 kW as roughing headroom
Tool capacity is 40, a working library rather than a generous one for a machine meant to turn, mill, drill and bore a large part complete in one setup
Footprint is 8,030 x 3,258 x 3,307 mm (316.14 x 128.27 x 130.20 in) for the 2,000 mm bed and 9,130 mm long for the 3,000 mm version - either needs a bay of its own with crane access along the full length
Long slender work will need steady rest support: the machine's capacity is in diameter and length, not in resisting deflection on its own

Best For

Large shafts, valve bodies and casings that currently pass through a big lathe and then a boring mill Oil and gas work - drill collars, spool bodies, long valve assemblies Power generation: turbine shafts, generator rotors, long cylindrical components Aerospace landing gear cylinders, actuator bodies and engine shafts Heavy equipment hydraulic cylinders, pump shafts and drivetrain components

Frequently Asked Questions

01 What size work does the MULTUS B550 handle?

Maximum machining diameter is 830 mm (32.68 in) around a 15-inch chuck on an A2-11 spindle nose. Maximum work length is 2,000 mm or 3,000 mm (78.74 or 118.11 in) depending on the bed specified. That combination puts it past general-purpose mill-turn work and into large flange, casing and rotor territory.

02 Why does the spindle stop at 3,000 min⁻¹?

Because it is sized for large diameters. At 830 mm a normal cutting speed is reached without much rotational speed at all, and the 30 min⁻¹ floor is arguably the more useful end of the range - it allows slow boring, threading and facing at large diameters under full load. Smaller-diameter features on the same part are where the ceiling shows.

03 How much power is available for sustained work?

The main spindle motor is rated 37/30 kW (50/40 hp) at 30 minutes and continuous respectively. Plan production programs against the 30 kW continuous figure; the 37 kW rating covers roughing bursts rather than a whole shift.

04 What does the W specification add?

A second spindle, used to finish the back end of the part in-cycle. On components two or three metres long that removes a re-fixture which would otherwise involve a crane, an operator and a fresh datum - the point at which most of the accumulated error on parts of this size gets introduced.

05 How much floor space does the B550 need?

The 2,000 mm machine measures 8,030 x 3,258 x 3,307 mm (316.14 x 128.27 x 130.20 in) and the 3,000 mm version is 9,130 mm long with the same width and height. Either version needs a bay of its own, with crane access along the full length for loading parts of this size.