Product Overview

The NMT 7013 CD/P4ADBD is a pre-assembled duplex back-to-back matched super-precision all-steel angular contact ball bearing set, comprising 2 rows of bearings precision-paired in a back-to-back (<>) configuration. With a total width of 36 mm (18 mm per row × 2), a 65 mm bore, and a 100 mm outer diameter, this set features a 15° contact angle (CD type) and D-type high-capacity design, combined with all-steel rolling elements and a phenolic resin cage, factory-preset with Class D heavy preload. This bearing set delivers ultimate bidirectional axial rigidity, overturning moment resistance, and high load capacity – the ultimate choice for heavy-cutting and high-rigidity spindle applications.

 

The bearing set offers a radial dynamic load rating of 67.6 kN (15,210 lbf) and a static load rating of 75 kN (16,875 lbf) . The DB back-to-back configuration extends the load action points outward, creating a maximum effective span that provides the highest overturning moment rigidity and bidirectional axial load capacity. Manufactured to the P4A super-precision tolerance class with a 15° contact angle and Class D heavy preload, the set achieves a limiting speed of 24,000 r/min. The bore and outside diameter matching precision is controlled within -0.004 mm to 0. The set weighs 0.86 kg with an operating temperature range of -30°C to 110°C.

 

Model Code Decoding – Understanding NMT 7013 CD/P4ADBD

Code Meaning

7013 Basic series designation, 65 mm bore (13×5 mm), 100 mm OD

CD 15° contact angle design – offers higher limiting speed and lower heat generation than 25° designs

P4A Super-precision tolerance class – superior to ABEC 7, bore and OD tolerances -0.004 mm to 0

DB Duplex Back-to-Back – 2 bearings mounted with contact angles facing outward (<>), providing maximum overturning rigidity and bidirectional axial load capacity

D Class D heavy preload – the highest preload level, delivering maximum internal contact stiffness for heavy-load high-speed applications

Core Configuration Insight: The DB back-to-back configuration (<>) extends the load action points outward, maximizing the effective span and significantly enhancing spindle resistance to bending moments. The CD-type 15° contact angle generates less frictional heat at equivalent speeds, offering higher limiting speed potential than 25° designs. The D-type high-capacity design, with optimized rolling element parameters (ball diameter 11.112 mm, 20 balls per bearing), achieves an outstanding 67.6 kN dynamic and 75 kN static load rating. Class D heavy preload provides maximized internal contact stiffness – the highest preload level in angular contact bearings – making it particularly suitable for heavy-load high-speed applications demanding ultimate rigidity. P4A super-precision ensures bore and OD tolerances are controlled within -0.004 mm to 0 – these five elements work together to make this bearing set the flagship precision bearing solution offering the perfect balance of ultimate overturning rigidity, high load capacity, and ultra-precision rotational accuracy. This is a non-universal matchable fixed set – the 2 bearings are factory end-face matched and must not be interchanged or mixed with other bearings.

 

Core Performance Advantages

1. Back-to-Back (DB) Configuration – Ultimate Overturning Rigidity and Bidirectional Load Capacity

The back-to-back (<> ) arrangement orients the contact angles outward in opposite directions, maximizing the effective span and providing the highest overturning moment rigidity. Whether facing axial load direction changes, radial cutting force fluctuations, or bending moment impacts, this configuration delivers the most stable rotational support. The precision-matched pair ensures uniform load distribution across both rows, significantly enhancing overall system rigidity.

 

2. 15° Contact Angle (CD Type) + D-Type High-Capacity Design – Ultra-High Speed and High Load Combined

The 15° small contact angle generates less frictional heat at equivalent speeds, offering higher limiting speed potential than 25° designs, with a limiting speed of 24,000 r/min under oil lubrication. The D-type high-capacity design, with optimized internal geometry and rolling element parameters (ball diameter 11.112 mm, 20 balls per bearing), achieves an outstanding 67.6 kN (15,210 lbf) dynamic and 75 kN (16,875 lbf) static load rating.

 

3. Class D Heavy Preload – The Ultimate Preload for High-Speed Heavy-Load Applications

Class D represents the highest preload level in angular contact bearings, providing maximized internal contact stiffness. Under heavy cutting, interrupted cutting, high feed rates, and other severe conditions, Class D preload effectively suppresses elastic deflection of the spindle under cutting forces, significantly enhancing machining accuracy and surface quality. For applications pursuing maximum metal removal rates, Class D preload is an indispensable choice.

 

4. P4A Super-Precision Grade – Micron-Level Spindle Accuracy

The P4A tolerance class (superior to ABEC 7) guarantees minimal radial runout and axial play. Both bearings undergo factory precision end-face matching grinding, with bore and OD tolerances controlled within -0.004 mm to 0, ensuring highly uniform load distribution across both rows, preventing individual bearing overload, and significantly extending overall set service life. Operating temperature range is -30°C to 110°C.

 

5. Lightweight Phenolic Resin Cage

The lightweight high-strength phenolic resin cage features a low friction coefficient, which helps reduce frictional heat generation at high speeds and minimize noise – a key factor in achieving the 24,000 r/min limiting speed.

 

6. All-Steel Construction – High Rigidity, Impact Resistance, Cost-Effectiveness

Premium chrome steel rings and balls offer higher fracture toughness and impact resistance than hybrid ceramic versions – more reliable under interrupted cutting and accidental overload conditions. All-steel bearings also offer significant cost advantages for high-volume industrial applications.

 

7. Open Design – Flexible Lubrication Options

This set features an open design, allowing flexible selection of lubrication methods based on application requirements – grease lubrication for general applications, oil or oil-air lubrication for high-speed heavy-load conditions.

 

8. Clear Performance Specifications

 

Parameter Value

Bore d 65 mm

Outer Diameter D 100 mm

Total Width B 36 mm (2×18 mm)

Contact Angle 15°

Dynamic Radial Load 67.6 kN (15,210 lbf)

Static Radial Load 75 kN (16,875 lbf)

Fatigue Load Limit Pu 3.15 kN

Ball Diameter Dw 11.112 mm

Balls per Bearing 20

Limiting Speed 24,000 r/min

Reference Grease Amount Gref 5.7 cm³

Ball Material Chrome Steel

Ring Material Chrome Steel

Cage Material Phenolic Resin

Seal Type Open

Tolerance Class P4A

Preload Class D (Heavy)

Arrangement Back-to-Back (<> ) DB

Bearings in Set 2

Weight 0.86 kg

Temperature Range -30°C to 110°C

Typical Applications

The NMT 7013 CD/P4ADBD, with its DB back-to-back ultimate overturning rigidity, D-type high-capacity design, Class D heavy preload, and P4A super-precision grade, covers an exceptionally wide range of heavy-duty high-end applications:

 

Heavy-Duty Machine Tool Spindles – heavy CNC machine tools, large precision grinders, milling center spindles

 

Heavy-Cutting Machining Centers – heavy cutting, high-feed-rate vertical/horizontal spindle systems

 

Heavy-Duty CNC Turning Centers – large-depth, high-feed turning spindles

 

Gear Cutting Machines – hobbing, shaping, milling, and grinding spindles

 

Large Mold Machining Centers – high-rigidity spindles for combined roughing and finishing

 

Aerospace Component Machining Equipment – high-speed heavy cutting of titanium and superalloys

 

Heavy-Duty Rotary Tables – high-accuracy heavy-load rotary positioning

 

Industrial Robots – high-rigidity transmission mechanisms and rotary axes

 

High-Precision Industrial Gearboxes – heavy-load precision transmission systems

 

Important Installation Notes

⚠️ This is a non-universal matchable fixed set (DB) – the 2 bearings are supplied as one complete unit. Do not interchange or mix with other bearings of the same model.

 

⚠️ The back-to-back configuration (<> ) is directional. Ensure the contact angles face outward to achieve the expected overturning rigidity.

 

✅ This set comes with factory-preset Class D heavy preload. No additional preload adjustment is required during installation. However, ensure shaft and housing fits comply with P4A grade requirements (bore/OD tolerance -0.004 mm to 0).

 

✅ This set is open design – select appropriate lubrication method based on application. To achieve the 24,000 r/min limiting speed, oil-air or oil-mist lubrication is recommended.

 

⚠️ Class D heavy preload generates significant operating temperature rise – ensure adequate thermal expansion compensation and sufficient heat dissipation from the lubrication system during installation. Reserve thermal expansion compensation space in the system design.

 

⚠️ Ensure shaft and housing bore concentricity and straightness meet P4A grade requirements to achieve the expected rotational accuracy and service life.

 

✅ Heat mounting or hydraulic installation methods are recommended to avoid damage during installation.

 

NMT Quality Commitment

Japan NMT (Enmutī) applies the most stringent end-face matching grinding and preload control to every DB back-to-back bearing set. All 2 bearings undergo complete factory matching and full-parameter inspection, ensuring load-sharing deviation between rows is minimized to an extremely small range. The 7013 CD/P4ADBD delivers P4A accuracy, 15° contact angle ultra-high-speed performance, D-type high-capacity design, DB back-to-back ultimate rigidity, and Class D heavy preload for unparalleled rotational support in your premier heavy-duty high-speed spindles.

 

Choose NMT 7013 CD/P4ADBD for:

 

✅ DB back-to-back configuration – ultimate overturning rigidity and bidirectional axial load capacity

 

✅ 15° contact angle + D-type high capacity – 67.6 kN (15,210 lbf) high load capacity

 

✅ Class D heavy preload – the ultimate choice for high-speed heavy-load applications

 

✅ P4A super-precision running accuracy – bore/OD tolerance -0.004 mm to 0

 

✅ 24,000 r/min ultra-high-speed performance

 

✅ All-steel – high rigidity, impact resistance, cost-effectiveness

 

✅ Phenolic resin cage – low friction, low noise, high speed

 

✅ Factory pre-matched – ready to install