Product Overview

The NMT 7013 ACD/P4ADBC 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 25° contact angle (AC type)  and D-type high-capacity design, combined with all-steel rolling elements and a phenolic resin cage, factory-preset with Class C moderate preload. It delivers ultimate system rigidity, exceptional overturning moment resistance, and bidirectional axial load capacity, accommodating radial and bidirectional axial loads simultaneously.

 

The bearing set offers a basic dynamic load rating of 63.8 kN (14,332 lbf) and a static load rating of 71.0 kN (15,975 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 D-type high-capacity design and Class C moderate preload, the set achieves a limiting speed of 31,000 r/min. The operating temperature range is -30°C to 110°C. The set weighs 0.84 – 0.86 kg.

 

Model Code Decoding – Understanding NMT 7013 ACD/P4ADBC

Code Meaning

7013 Basic series designation, 65 mm bore, 100 mm OD

AC Angular contact design with 25° contact angle

D D-type high-capacity design – optimized internal geometry, best suited for heavier loads compared to equivalent B and E type high-speed bearings

P4A Super-precision tolerance class – bore and OD tolerances -0.004mm to 0

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

C Class C moderate preload – optimized internal contact stiffness for high-speed heavy-load applications

Core Value: 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 AC-type 25° contact angle delivers superior axial rigidity and radial load capacity. The D-type high-capacity design is best suited for heavier loads compared to equivalent B and E type high-speed bearings. Class C moderate preload provides the optimal balance between high-speed capability and system rigidity. P4A super-precision ensures bore and OD tolerances are controlled within -0.004mm 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, with bore and OD matching precision controlled within one-third of the allowable tolerance, 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. 25° Contact Angle (AC Type) + D-Type High-Capacity Design – High Load and High Rigidity Combined

The 25° contact angle delivers superior axial rigidity while maintaining ample radial capacity. The D-type high-capacity design, with optimized internal geometry and rolling element parameters (ball diameter 11.112 mm, 20 balls per bearing), is best suited for heavier loads compared to equivalent B and E type high-speed bearings. It achieves an outstanding 63.8 kN (14,332 lbf) dynamic and 71.0 kN (15,975 lbf) static load rating within a compact 36 mm total width. The set weighs 0.84 – 0.86 kg.

 

3. Class C Moderate Preload – Ideal for High-Speed Heavy-Load Applications

Class C moderate preload provides "just-right" internal contact stiffness for high-speed spindles – eliminating internal clearance, reducing vibration and noise at high speeds, while avoiding excessive temperature rise from over-preloading. This ensures stable temperature performance even at 31,000 r/min limiting speeds.

 

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

The P4A tolerance class guarantees minimal radial runout and axial play. Bore and outside diameter tolerances are -0.004mm to 0, meeting stringent surface quality and dimensional consistency requirements. Operating temperature range is -30°C to 110°C.

 

5. Lightweight Phenolic Resin Cage

The lightweight high-strength phenolic resin cage provides excellent guidance accuracy and low friction at high speeds, contributing to reduced centrifugal forces, friction, and heat generation – a key factor in achieving the 31,000 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. Clear Performance Specifications

 

Parameter Value

Bore d 65 mm

Outer Diameter D 100 mm

Total Width B 36 mm (2×18 mm)

Contact Angle 25°

Dynamic Load Rating 63.8 kN (14,332 lbf)

Static Load Rating 71.0 kN (15,975 lbf)

Ball Diameter Dw 11.112 mm

Balls per Bearing 20

Limiting Speed 31,000 r/min

Ball Material Chrome Steel

Ring Material Chrome Steel

Cage Material Phenolic

Seal Type Open

Tolerance Class P4A

Preload Class C (Moderate)

Arrangement Back-to-Back (<> ) DB

Bearings in Set 2

Weight 0.84 – 0.86 kg

Temperature Range -30°C to 110°C

Typical Applications

The NMT 7013 ACD/P4ADBC, with its DB back-to-back ultimate overturning rigidity, D-type high-capacity design, and P4A super-precision grade, covers an exceptionally wide range of high-end applications:

 

High-Speed Machine Tool Spindles – CNC machine tools, precision grinders, milling center spindles

 

High-Speed Electric Spindles – high-speed rotary units

 

Machining Center Spindles – vertical/horizontal spindle systems

 

Precision Rotary Tables – high-accuracy rotary positioning

 

Aerospace Components – gyroscopes, actuators, jet engine parts

 

Medical Equipment – high-speed dental drills and medical imaging devices

 

Semiconductor Manufacturing Equipment – precision wafer processing spindles

 

Industrial Robots – high-precision transmission mechanisms and rotary axes

 

High-Precision Industrial Gearboxes – precision transmission systems

 

Pumps and Compressors – high-speed rotating machinery

 

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 C moderate preload. No additional preload adjustment is required during installation. However, ensure shaft and housing fits comply with P4A grade requirements (bore/OD tolerance -0.004mm to 0).

 

✅ This set is open design – select appropriate lubrication method based on application. To achieve the 31,000 r/min limiting speed, oil-air or oil-mist lubrication is recommended.

 

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

 

✅ Bore and OD matching precision is controlled within one-third of the allowable tolerance, ensuring uniform load distribution across both rows.

 

NMT Quality Commitment

Japan NMT (Enmutī) applies strict Japanese quality standards to every 7013 ACD/P4ADBC bearing set – from ring material (high-purity chrome steel) and rolling elements to superfinishing processes. Every DB back-to-back set undergoes factory end-face matching grinding and Class C moderate preload setting, with bore and OD matching precision controlled within one-third of the allowable tolerance, ensuring load-sharing deviation between the two rows is minimized to an extremely small range. The combination of 25° contact angle (AC type), D-type high-capacity design, DB back-to-back ultimate rigidity, P4A precision, and Class C moderate preload makes this bearing set the flagship precision bearing solution in the NMT 7013 series – offering the perfect balance of ultimate overturning rigidity, high load capacity, and ultra-precision rotational accuracy.

 

Choose NMT 7013 ACD/P4ADBC for:

 

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

 

✅ 25° contact angle + D-type high capacity – 63.8 kN high load capacity

 

✅ Class C moderate preload – ideal for high-speed heavy-load applications

 

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

 

✅ 31,000 r/min ultra-high-speed performance

 

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

 

✅ Factory pre-matched – matching precision within one-third of tolerance

 

✅ -30°C to 110°C wide temperature range capability