Citizen Miyano BNJ-51SY

$250,000 - $360,000 Updated 2025-03-15

Key Specifications

max bar capacity sp1

51 mm (2.0 in)

max bar capacity sp2

42 mm (1.65 in)

main spindle speed

5,000 RPM

main spindle power

15/11 kW (20/15 hp)

sub spindle speed

5,000 RPM

sub spindle power

7.5/5.5 kW (10/7.5 hp)

Overview

The Citizen Miyano BNJ-51SY is a dual-spindle, twin-turret fixed-headstock CNC turning center with Y-axis that delivers true simultaneous independent machining from 51 mm bar stock. The BNJ platform pairs a 12-station upper turret with an 8-station lower turret, enabling both spindles to machine with dedicated tooling at the same time for minimum cycle times on complex parts.

The main spindle (SP1) reaches 5,000 RPM with 15/11 kW (20/15 hp), while the sub-spindle (SP2) runs to 5,000 RPM with 7.5/5.5 kW (10/7.5 hp). The main spindle accepts 51 mm bar stock while the sub-spindle handles 42 mm. Both spindles support collet and power chuck workholding. The 825 mm distance between spindle faces provides generous clearance for the twin-turret arrangement and part transfer operations.

The upper turret (HD1) has 12 stations with live tools at 6,000 RPM and 2.2 kW rotary tool power, plus Y-axis travel of 80 mm (+/-40 mm) for off-center machining. The lower turret (HD2) adds 8 stations with live tools at 6,000 RPM and 0.75 kW, primarily handling backworking operations on the sub-spindle. The twin-turret design means the upper and lower turrets can machine simultaneously and independently — no time-sharing, no superimposition compromise.

Axis travels measure 168 mm on X1, 250 mm on Z1, 88 mm on X2, and 650 mm on Z2. Seven cutting axes provide the motion freedom for complex multi-path programming. The Fanuc 0i-TF control with 10.4-inch color LCD manages dual-path synchronization and supports 800 registered programs. Rapid traverse rates keep repositioning time low.

At 5,550 kg with a floor space of 2,881 x 1,578 mm, the BNJ-51SY is a substantial machine built for production environments where cycle time directly impacts profitability. The 7th generation (SY6) brings improved turret rigidity and updated control features over earlier models.

The BNJ-51SY sits above the single-turret BND-51SY in capability and price, offering the twin-turret simultaneous machining that justifies its premium for high-volume production. It competes with the Nakamura-Tome WY-150 and Tsugami B0656-III in the premium 51 mm twin-turret segment. Typical applications include automotive transmission components, hydraulic fittings, medical device housings, and industrial connectors where the twin-turret architecture shaves critical seconds from every cycle.

Full Specifications

Parameter	Value
Max Bar Capacity Sp1	51 mm (2.0 in)
Max Bar Capacity Sp2	42 mm (1.65 in)
Main Spindle Speed	5,000 RPM
Main Spindle Power	15/11 kW (20/15 hp)
Sub Spindle Speed	5,000 RPM
Sub Spindle Power	7.5/5.5 kW (10/7.5 hp)
Upper Turret Stations	12
Lower Turret Stations	8
Upper Turret Live Tool Speed	6,000 RPM
Upper Turret Live Tool Power	2.2 kW
Lower Turret Live Tool Speed	6,000 RPM
Lower Turret Live Tool Power	0.75 kW
Travel X1	168 mm (6.61 in)
Travel Z1	250 mm (9.84 in)
Travel X2	88 mm (3.46 in)
Travel Z2	650 mm (25.59 in)
Y Axis Travel	80 mm (+/-40 mm)
Number Of Axes	7 cutting axes
Distance Between Spindles	825 mm
Machine Weight	5,550 kg
Floor Space	2,881 x 1,578 mm
CNC Control	Fanuc 0i-TF
Items	BNJ-51SY7
Machining Capacity	Distance between spindle end faces
Standard Machining Diameter	SP1
Sp2	H-S22、H-S20、DIN173E
Spindle	Max. spindle speed
Collet Chuck Type	SP1
Power Chuck Type	SP1/SP2
Tool Slide	Type of tool slide
Tr2	MAX M12×1.75(S45C)
Revolving Tool	Revolving tool capacity
Rotational Speed Of Revolving Tools	TR1
Max Drilling Diameter	TR1
Max Tapping Diameter	TR1
Slide Stroke	Turret slide stroke
Z1 Axis	250mm
Y Axis	±40mm
Spindle Slide Stroke	X2 axis
Z2 Axis	650mm
Motor	Motor for spindle
Sp2 Cs	7.5/5.5kw (15 min/cont.)
Machine Size	Machine height
Machine Body Dimensions	2,881×1,578mm
Sliding Headstock Type	A20
Bar Work	BNC42
Turning Machine	BNA42CY
High Precision Turning Machines	BNA42SY
Multi Station Machining Cell	MC20 III
Distance Between Spindle End Faces	825mm
Standard Workpiece Collection Length	120 mm
Standard Machining Diametersp1 Sp2	51 mm
Max Spindle Speed Sp1 Sp2	5,000 min-1
Collet Chuck Typesp1	H-S22、DIN177E、Hainbuch 51
Collet Chuck Typesp2	H-S22、H-S20、DIN173E
Power Chuck Type Sp1 Sp2	6"/5"hollow chuck
Type Of Tool Slidetr1	12st.
Type Of Tool Slidetr2	8st.
Revolving Tool Capacitytr1	Max.12
Revolving Tool Capacitytr2	Max.8
Rotational Speed Of Revolving Tools Tr1 Tr2	6,000min-1
Max Drilling Diameter Tr1 Tr2	MAX ø13mm
Max Tapping Diameter Tr1 Tr2	MAX M12×1.75(S45C)
Turret Slide Stroke X1 Axis	168mm
Turret Slide Stroke Z1 Axis	250mm
Turret Slide Stroke Y Axis	±40mm
Spindle Slide Stroke X2 Axis	88mm
Spindle Slide Stroke Z2 Axis	650mm
Motor For Spindle Sp1 Cs	15/11kw (15 min/cont.)
Motor For Spindle Sp2 Cs	7.5/5.5kw (15 min/cont.)
Machine Height	1,775mm
Inquiries	Feel free to get in touch with us by phone or online if you have any questions or need advice about any of our products or services.

Specifications sourced from cmj.citizen.co.jp — verified 2026-03-28

Strengths & Limitations

Strengths

True twin-turret independence with 12+8 stations enables simultaneous machining on both spindles with no time-sharing, reducing cycle times 30-50% versus single-turret machines on complex parts
6,000 RPM live tools on both turrets provide milling capability for cross-drilling, tapping, and off-center features on both front and back of the workpiece
Y-axis travel of 80 mm on the upper turret handles complex off-center milling for flats, keyways, and hexagonal profiles on the main spindle
650 mm Z2 sub-spindle travel provides exceptional clearance for part pickup and backworking, handling longer parts without interference
Fanuc 0i-TF control offers broad CAM post processor compatibility and is familiar to the majority of CNC programmers in the market
15/11 kW main spindle delivers 20/15 hp for aggressive roughing at the 51 mm bar diameter in steel and stainless materials

Limitations

0.75 kW lower turret live tool power is modest, limiting the aggressiveness of backworking milling operations to light cross-drilling and tapping
42 mm sub-spindle capacity is smaller than the 51 mm main spindle, restricting full-diameter backworking on the largest parts
5,550 kg weight and 2,881 x 1,578 mm footprint require significant floor space and foundation work compared to single-turret alternatives
Twin-turret programming complexity requires experienced multi-path programmers and collision simulation software
Higher acquisition cost versus single-turret BND-51SY only pays off on parts with substantial simultaneous machining potential

Best For

Automotive transmission component production where twin-turret simultaneous machining shaves critical seconds from high-volume cycle times Hydraulic fitting and connector manufacturers running large quantities of parts with balanced front-and-back complexity Medical device housing production where the twin-turret reduces cycle time enough to justify the premium over single-turret machines Industrial connector and coupling manufacturers producing parts from 51 mm bar with cross-drilling and threading on both ends Shops running the BND-51SY at capacity that need to increase throughput without adding a second machine Contract manufacturers with high-volume parts where cycle time savings of 5-15 seconds per part add up to significant annual cost reduction

Frequently Asked Questions

01 What does a new Citizen Miyano BNJ-51SY cost?

New BNJ-51SY6 (7th generation) machines typically range from $250,000 to $360,000 depending on tooling configuration, high-pressure coolant, bar feeder, and parts catcher. The twin-turret design commands a $70,000-$100,000 premium over the single-turret BND-51SY. Used BNJ-51SY machines from 2014-2020 sell for $100,000-$220,000.

02 Why does the lower turret have less live tool power than the upper?

The lower turret's 0.75 kW motor is designed for lighter backworking operations — cross-drilling, tapping, and light milling on the sub-spindle. The upper turret's 2.2 kW motor handles the heavier milling work on the main spindle. This asymmetric design reflects the typical part: most milling complexity is on the front end, while backworking is often limited to threading, facing, and a few cross-holes.

03 How does the BNJ-51SY compare to the BNE-51MSY?

The BNE-51MSY has twin 12+12 turrets (24 total stations), a third axis group (X3/Z3) for the sub-spindle, and 2.2 kW live tool motors on both turrets. The BNJ has 12+8 (20 total stations) with asymmetric tool power. The BNE is more capable and expensive, designed for the most complex parts. The BNJ is a better value for parts that don't need maximum lower-turret milling power.

04 What generation is the current BNJ-51SY?

The current model is the BNJ-51SY6 (7th generation), featuring the Fanuc 0i-TF control with 10.4-inch color LCD and 800-program storage. Each generation has brought incremental improvements in turret rigidity, spindle performance, and control features. The 7th generation is a mature, well-proven design.

05 Can the BNJ-51SY handle chucker work alongside bar-fed production?

Yes. The machine supports both collet and power chuck workholding. With power chucks, it handles castings, forgings, and pre-cut blanks for chucker-style machining. The 51 mm bar capacity works with magazine-style bar feeders for continuous production runs. Most shops maintain both setups for flexibility.

06 What bar feeders are compatible with the BNJ-51SY?

Common pairings include the LNS Quick Load Servo 80, Edge FMB Turbo 5-65, and Iemca Master 80, all rated for 51 mm (2-inch) bar stock. Magazine-style feeders are preferred for production runs. The bar feeder interface is standard across the Miyano platform, and most shops choose based on existing feeder brand preferences.