Kuraki KBT-13A

$450,000 - $700,000 Updated 2026-03-14

Key Specifications

X Travel

2,500 mm (98.4 in)

Y Travel

2,000 mm (78.7 in)

Z Travel

1,500 mm (59.1 in)

Rapid Traverse

8 m/min (315 IPM)

Spindle Power

30 kW (40 HP)

spindle diameter

130 mm (5.1 in)

Overview

The Kuraki KBT-13A is a horizontal boring mill with a 130 mm (5.1 inch) spindle diameter, positioning it as a mid-range floor-type boring machine for heavy industrial machining. Kuraki has been building horizontal boring mills since the 1930s, and the KBT-13A reflects decades of accumulated knowledge in large-workpiece precision machining. The machine handles the kind of work that keeps heavy industry running — engine blocks, gearbox housings, pump casings, turbine components, and large valve bodies that require precise bore relationships across multiple faces.

The 130 mm quill-type spindle provides the rigidity needed for heavy boring operations in cast iron and steel. Spindle speeds range from 5 to 2,000 RPM with a 30 kW main motor, giving operators the flexibility to run large-diameter facing heads at low RPM or small boring bars at higher speeds. The quill extends 600 mm, and W-axis (spindle feed) resolution ensures precise depth control during boring operations. X-axis travel of 2,500 mm, Y-axis of 2,000 mm, and Z-axis (column travel) of 1,500 mm provide the working envelope for large industrial components.

The floor-type configuration with a rotary table rated for heavy loads allows the workpiece to be indexed to machine multiple faces without unclamping. The rotary table provides 360-degree indexing with positioning accuracy of 5 arc-seconds, which is critical when boring holes that must maintain precise angular relationships. Table load capacity of 15,000 kg handles the castings and weldments typical in power generation, mining, and heavy equipment manufacturing.

Kuraki builds the KBT-13A with hand-scraped guideways on all major axes. This is not a cost-cutting shortcut — hand scraping provides superior damping characteristics compared to ground guideways, which translates directly into better surface finishes during heavy interrupted cuts on large castings. The Fanuc 31i-B control with manual pulse generator gives experienced boring mill operators the blend of CNC precision and hands-on feel they need for setup and first-article work on large complex parts.

Full Specifications

Parameter	Value
Spindle Diameter	130 mm (5.1 in)
Spindle Speed	5 - 2,000 RPM
Spindle Motor Power	30 kW (40 HP)
Spindle Quill Travel	600 mm (23.6 in)
X-Axis Travel	2,500 mm (98.4 in)
Y-Axis Travel	2,000 mm (78.7 in)
Z-Axis Travel	1,500 mm (59.1 in)
Rotary Table Size	1,600 x 1,800 mm (63 x 71 in)
Max Table Load	15,000 kg (33,069 lb)
Table Indexing Accuracy	5 arc-seconds
Rapid Traverse Rate	8 m/min (315 IPM)
Facing Head	Optional, up to 1,000 mm diameter
CNC Control	Fanuc 31i-B
Machine Weight	32,000 kg (70,548 lb)
Tool Magazine	60-tool ATC (optional)
Spindle Size	7.87 in
X Horiz Tvl Of Table	118.11 in

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

Strengths & Limitations

Strengths

130 mm spindle diameter provides exceptional rigidity for heavy boring operations in large castings and weldments
Hand-scraped guideways deliver superior vibration damping and surface finish quality compared to ground guideways
15,000 kg table capacity handles the heaviest castings found in power generation and heavy equipment manufacturing
Rotary table with 5 arc-second indexing accuracy enables precise multi-face machining without unclamping
Kuraki's decades of horizontal boring mill specialization shows in the machine's design maturity and reliability
30 kW spindle motor provides ample power for both heavy roughing with large boring bars and finish boring operations

Limitations

Large footprint and 32,000 kg machine weight require substantial foundation preparation and floor loading capacity
8 m/min rapid traverse is slow by modern standards, extending non-cutting time on large parts with widely spaced features
Kuraki's North American dealer and service network is smaller than TOS, Doosan, or Toshiba boring mill operations
Floor-type design requires more operator skill for workpiece setup than modern table-type HBMs with pallet changers
Lead time on new machines can extend to 12-18 months depending on configuration and Kuraki's production schedule

Best For

Heavy equipment manufacturers machining large castings for mining, construction, and industrial machinery Power generation facilities boring turbine casings, generator frames, and large valve bodies Oil and gas industry shops machining wellhead components, BOP housings, and large pump casings General heavy machining job shops handling a variety of large industrial castings and weldments Shipyard machine shops boring engine blocks, reduction gear housings, and propeller shaft components Facilities needing precise multi-face boring on heavy parts with tight geometric tolerances

Frequently Asked Questions

01 What does a Kuraki KBT-13A cost?

New Kuraki KBT-13A machines typically price between $450,000 and $700,000 depending on table size, ATC options, and accessories. Used machines from the 2000s-2010s trade in the $150,000-$350,000 range. Installation costs including foundation work can add $30,000-$80,000.

02 How does the Kuraki KBT-13A compare to a Toshiba BTD series?

Both are respected Japanese horizontal boring mills. The Toshiba BTD series tends to offer higher rapid traverse speeds and more modern CNC features, while the Kuraki KBT series is known for its hand-scraped guideways and traditional boring mill rigidity. The Kuraki typically costs less than a comparably sized Toshiba.

03 What is the advantage of hand-scraped guideways?

Hand-scraped guideways provide superior vibration damping, better oil retention, and more consistent slide motion compared to ground guideways. This translates to better surface finishes during heavy interrupted cuts and longer guideway life. The trade-off is slower rapid traverse speeds.

04 Can the KBT-13A use automatic tool changing?

Yes. A 60-tool ATC is available as an option. However, many boring mill operators prefer manual tool changes for the flexibility of using long boring bars and special tooling that does not fit in standard ATC magazines.

05 What foundation is required for the KBT-13A?

At 32,000 kg, the KBT-13A requires a reinforced concrete foundation designed specifically for the machine's weight distribution and dynamic loads. Kuraki provides foundation drawings with the machine order. Most installations require 300-500 mm thick reinforced concrete with isolation from surrounding floor vibration.