Product Overview

The NMT 7014 CD/P4AQBCA 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 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 A extra light preload, delivering ultimate bidirectional axial rigidity, overturning moment resistance, and high load capacity.

 

The bearing set offers a radial dynamic load rating of 30,375 lbf (135.1 kN) and a static load rating of 41,175 lbf (183.1 kN) . The QBC 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 A extra light preload, the set achieves a limiting speed of 22,000 r/min. The bore and outside diameter matching precision is controlled within -0.004 mm to 0. The set weighs 2.38 kg with an operating temperature range of -30°C to 110°C.

 

Model Code Decoding – Understanding NMT 7014 CD/P4AQBCA

Code Meaning

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

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

P4A Super-precision tolerance class – surpassing ABEC 7 standards, running accuracy superior to ISO P4

QBC Quadruplex QBC arrangement (Quadruplex Back-to-Back-Cascade) – 4 bearings arranged in tandem-back-to-back-tandem (<<>>) configuration

A Class A extra light preload – ideal for high-speed precision applications

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. The bore and outside diameters of the bearings are matched to within a maximum of one-third of the permitted diameter tolerance, ensuring highly uniform load distribution across all 4 rows. 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, effectively resisting bending and eccentric 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 30,375 lbf (135.1 kN) , static load rating 41,175 lbf (183.1 kN) – nearly quadruple single-row capacity

 

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. The D-type high-capacity design, with optimized rolling element parameters – ball diameter 12.7 mm, 19 balls per bearing – achieves an outstanding 135.1 kN dynamic and 183.1 kN static load rating, creating an exceptionally rigid bearing system within a compact 80 mm total width.

 

3. Class A Extra Light Preload – Precision Stiffness at Speed Limits

Class A extra light 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 22,000 r/min limiting speed.

 

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

The P4A tolerance class (surpassing ABEC 7) 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, with bore and OD matching precision controlled within one-third of the allowable tolerance, 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 22,000 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 – 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 (unsealed), allowing flexible selection of lubrication methods based on application requirements, and facilitating efficient heat dissipation and easy relubrication. Grease lubrication limits speed to 12,000 r/min, oil lubrication to 19,000 r/min.

 

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 15°

Dynamic Radial Load 30,375 lbf (135.1 kN)

Static Radial Load 41,175 lbf (183.1 kN)

Ball Diameter Dw 12.7 mm

Balls per Bearing 19

Limiting Speed 22,000 r/min

Speed (Grease) 12,000 r/min

Speed (Oil) 19,000 r/min

Ball Material Chrome Steel

Ring Material Chrome Steel

Cage Material Phenolic Resin

Seal Type Open

Tolerance Class P4A

Preload Class A (Extra Light)

Arrangement QBC (<<>>)

Bearings in Set 4

Weight 2.38 kg

Temperature Range -30°C to 110°C

Typical Applications

The NMT 7014 CD/P4AQBCA is engineered for premium precision equipment demanding ultimate system rigidity, high load capacity, and uncompromising accuracy:

 

High-Speed Machine Tool Spindles – CNC machine tools, precision grinders, jig boring machines

 

High-Speed Electric Spindles – high-speed rotary units

 

Machining Center Spindles – vertical/horizontal spindle systems

 

Precision Rotary Tables – high-accuracy heavy-load 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

 

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 A extra light preload. No additional preload adjustment is required during installation. Bore and OD matching precision is controlled within one-third of the allowable tolerance – ensure shaft and housing fits comply with P4A grade requirements (bore/OD tolerance -0.004 mm to 0).

 

✅ To achieve the 22,000 r/min limiting speed, oil lubrication is recommended; grease lubrication limits speed to 12,000 r/min.

 

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

 

✅ This set features an open design, allowing flexible lubrication selection based on application.

 

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, with bore and OD matching precision controlled within one-third of the allowable tolerance, ensuring load-sharing deviation between rows is minimized to an extremely small range. The 7014 CD/P4AQBCA delivers P4A accuracy, 15° contact angle ultra-high-speed performance, D-type high-capacity design, QBC quadruplex ultimate rigidity, and Class A extra light preload for unparalleled rotational support in your premier high-speed spindles.

 

Choose NMT 7014 CD/P4AQBCA for:

 

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

 

✅ 15° contact angle + D-type high capacity – 135.1 kN (30,375 lbf) high load capacity

 

✅ Class A extra light preload – precision stiffness at speed limits

 

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

 

✅ 22,000 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 – matching precision within one-third of tolerance