Product Overview

The NMT 7014 ACD/P4AQBCC is a pre-assembled quadruplex QBC matched super-precision all-steel angular contact ball bearing set, comprising 4 rows of bearings precision-paired in a tandem-back-to-back-tandem (<<>>) QBC configuration. With a total width of 80 mm (20 mm per row × 4), a 70 mm bore, and a 110 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, delivering ultimate bidirectional axial rigidity, overturning moment resistance, and high load capacity.

 

The bearing set offers a radial dynamic load rating of 28,575 lbf (127.1 kN) and a static load rating of 38,925 lbf (173.2 kN) . The QBCC configuration indicates that this set consists of 4 fully matched bearings arranged in a QBC (tandem-back-to-back-tandem) configuration, providing the highest system rigidity and bidirectional axial load capacity. Manufactured to the P4A super-precision tolerance class with Class C moderate preload, the set achieves a maximum speed of 29,000 r/min. The bore and outside diameter matching precision is controlled within -0.004 mm to 0. The set weighs 2.38 kgwith an operating temperature range of -30°C to 110°C.

 

Model Code Decoding – Understanding NMT 7014 ACD/P4AQBCC

Code Meaning

7014 Basic series designation, 70 mm bore (14×5 mm), 110 mm OD

AC Angular contact design with 25° contact angle

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

P4A Super-precision tolerance class – surpassing ABEC 7/ISO P4 standards, bore and OD tolerances -0.004 mm to 0

QBCC Quadruplex QBC arrangement + Class C preload – 4 bearings arranged in tandem-back-to-back-tandem (<<>>) QBC configuration, factory-preset Class C moderate preload

Core Configuration Insight: The QBC (<<>>) configuration consists of 4 bearing rows – the center two in back-to-back (<> ) providing maximum overturning rigidity, with one tandem (>>) row on each side doubling unidirectional axial load capacity. This represents the highest rigidity and highest load capacity configuration available in angular contact bearing arrangements. This is a non-universal matchable fixed set – the 4 bearings are factory end-face matched and must not be interchanged or mixed with other bearings.

 

Core Performance Advantages

1. QBC Quadruplex Configuration – Ultimate System Rigidity and Bidirectional Axial Load Capacity

The QBC (<<>>) configuration combines the dual advantages of back-to-back (<> ) and tandem (>>) arrangements:

 

Center two rows back-to-back: Provides maximum overturning moment rigidity, minimizing deflection under heavy loads

 

One tandem row on each side: Doubles unidirectional axial load capacity on each side, with symmetric layout achieving perfect bidirectional axial load balance

 

Dynamic load rating 28,575 lbf (127.1 kN) , static load rating 38,925 lbf (173.2 kN) – nearly quadruple single-row capacity

 

2. 25° Contact Angle (AC Type) + D-Type High-Capacity Design – Powerful Combined Load Capacity

The 25° contact angle delivers superior axial rigidity while maintaining ample radial capacity. The D-type high-capacity design, with optimized rolling element parameters – ball diameter 12.7 mm, 19 balls per bearing– is best suited for heavier loads compared to equivalent B and E type high-speed bearings, achieving an outstanding 127.1 kN dynamic and 173.2 kN static load rating within a compact 80 mm total width.

 

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 the 29,000 r/min maximum speed.

 

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

The P4A tolerance class (surpassing ABEC 7/ISO P4 standards) guarantees minimal radial runout and axial play. Bore and outside diameter tolerances are -0.004 mm to 0. All 4 bearings undergo factory precision end-face matching grinding, ensuring highly uniform load distribution across all 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 – Speed and Durability Combined

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 29,000 r/min maximum speed.

 

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

Premium chrome steel rings and ballsoffer higher fracture toughness and impact resistance – 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, and facilitating easy maintenance and relubrication. The set comes pre-lubricated from the factory – ready to install out of the box.

 

8. Clear Performance Specifications

 

Parameter Value

Bore d 70 mm

Outer Diameter D 110 mm

Total Width B 80 mm (4×20 mm)

Contact Angle 25°

Dynamic Radial Load 28,575 lbf (127.1 kN)

Static Radial Load 38,925 lbf (173.2 kN)

Ball Diameter Dw 12.7 mm

Balls per Bearing 19

Maximum Speed 29,000 r/min

Ball Material Chrome Steel

Ring Material Chrome Steel

Cage Material Phenolic Resin

Seal Type Open (Pre-lubricated)

Tolerance Class P4A

Preload Class C (Moderate)

Arrangement QBC (<<>>)

Bearings in Set 4

Weight 2.38 kg

Temperature Range -30°C to 110°C

Typical Applications

The NMT 7014 ACD/P4AQBCC is engineered for premium precision equipment demanding ultimate system rigidity, high load capacity, and uncompromising accuracy:

 

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

 

Heavy-Duty Machining Centers – large-depth, high-feed vertical/horizontal spindle systems

 

Aerospace Component Machining Equipment – gyroscopes, actuators, jet engine parts

 

High-Speed Rotating Machinery – high-speed drilling and milling machines

 

Precision Rotary Tables – high-accuracy heavy-load rotary positioning

 

Semiconductor Manufacturing Equipment – precision wafer processing spindles

 

Medical Equipment – high-speed medical imaging devices

 

Industrial Robots – high-precision transmission mechanisms and rotary axes

 

Important Installation Notes

⚠️ This is a non-universal matchable fixed set (QBC) – the 4 bearings are supplied as one complete unit. Do not interchange or mix with other bearings of the same model.

 

⚠️ The QBC (<<>>) configuration is strictly directional. Installation must strictly follow NMT's assembly drawings to ensure correct contact angle orientation for each row. Incorrect orientation will completely eliminate load capacity.

 

✅ 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 -0.004 mm to 0).

 

✅ To achieve the 29,000 r/min maximum speed, oil-air or oil-mist lubrication is recommended. This set features an open design, allowing flexible lubrication selection based on application.

 

⚠️ Total width is 80 mm. Ensure sufficient axial installation space.

 

✅ This set comes pre-lubricated from the factory – ready to install out of the box.

 

NMT Quality Commitment

Japan NMT (Enmutī) applies the most stringent end-face matching grinding and preload control to every QBC quadruplex bearing set. All 4 bearings undergo complete factory matching and full-parameter inspection, ensuring load-sharing deviation between rows is minimized to an extremely small range. The 7014 ACD/P4AQBCC delivers P4A accuracy, 25° contact angle high rigidity, D-type high-capacity design, QBC quadruplex ultimate rigidity, and Class C moderate preload for unparalleled rotational support in your premier heavy-duty high-speed spindles.

 

Choose NMT 7014 ACD/P4AQBCC for:

 

✅ QBC quadruplex configuration – ultimate system rigidity and bidirectional load capacity

 

✅ 25° contact angle + D-type high capacity – 127.1 kN (28,575 lbf) high load capacity

 

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

 

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

 

✅ 29,000 r/min ultra-high-speed performance

 

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

 

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

 

✅ Factory pre-matched and pre-lubricated – ready to install