Product Overview

The NMT 7001 ACEGB/HCP4A is an open, universally matchable single-row super-precision hybrid ceramic angular contact ball bearing. With a 12 mm bore, 28 mm outer diameter, and 8 mm width, this bearing features a 25° contact angle and high-speed E-type design, combined with silicon nitride (Si₃N₄) hybrid ceramic rolling elements (HC) and a phenolic resin cage, factory-preset with Class B light preload (GB) . It integrates high axial rigidity, high load capacity, ultra-high-speed performance, super-precision rotational accuracy, and flexible arrangement capability into a single package, accommodating radial and unidirectional axial loads simultaneously.

 

The bearing offers a radial dynamic load rating of 691 lbf (3.07 kN) and a static load rating of 286 lbf (1.27 kN) . Manufactured to the P4A super-precision tolerance class with a 25° contact angle, hybrid ceramic technology, and Class B light preload, the bearing achieves a limiting speed of 110,000 r/min. The bearing weighs only 0.019 – 0.022 kg (19 – 22 g)  with an operating temperature range of -30°C to 110°C.

 

Model Code Decoding – Understanding NMT 7001 ACEGB/HCP4A

Code Meaning

7001 Basic series designation, 12 mm bore, 28 mm OD, 8 mm width

AC Angular contact design with 25° contact angle – provides superior axial rigidity and radial load capacity

E High-speed E-type design – offers higher speed capability and can accommodate heavier loads than equivalent B-type designs

G Universally matchable – any two bearings of the same model can be directly paired

B Class B light preload – light preload for face-to-face or back-to-back arrangements

HC Hybrid ceramic – rolling elements made of bearing-grade silicon nitride (Si₃N₄) 

P4A Super-precision tolerance class – superior to ABEC 7 standards

Core Value: GB universal matchability (SU) means every NMT 7001 ACEGB/HCP4A bearing's end-face height difference and parallelism are tightly controlled, allowing any two bearings of the same model to be directly paired without selective shimming or additional grinding, providing effective load sharing within a predetermined preload range. The AC-type 25° contact angle provides superior axial rigidity and radial load capacity. The E-type high-speed design offers higher speed capability than equivalent B-type designs. HC hybrid ceramic technology drastically reduces centrifugal forces and frictional heat at high speeds. Class B light preload eliminates internal clearance, improving system rigidity and shaft positioning accuracy. P4A super-precision ensures bore and OD tolerances are controlled within -0.004 mm to 0 – these six elements work together to make this bearing the flagship precision bearing solution for miniature high-rigidity spindles.

 

Core Performance Advantages

1. 25° Contact Angle – High Axial Rigidity and Load Capacity

The 25° contact angle is one of the highest axial rigidity contact angle designs available in angular contact ball bearings. With a ball diameter of 3.969 mm and 12 ceramic balls per bearing, it provides superior axial and radial load capacity. In applications subjected to heavy axial loads, the 25° contact angle more effectively resists axial displacement, ensuring machining accuracy and spindle stability.

 

2. Hybrid Ceramic Technology – The Foundation of Ultra-High-Speed Performance

Silicon nitride (Si₃N₄) ceramic balls have only 60% the density of bearing steel, drastically reducing centrifugal forces and frictional heat at high speeds. Ceramic materials also offer lower thermal expansion coefficients and higher elastic modulus, effectively suppressing geometric deformation at high speeds. Combined with chrome steel rings and a phenolic resin cage, this achieves the perfect balance of high rigidity, ultra-high speed, and durability.

 

3. High-Speed E-Type Design – Ultra-High Speed and Heavy Load Combined

The E-type high-speed design optimizes internal geometry and rolling element parameters, significantly reducing sliding friction and churning losses at high speeds. Compared to equivalent B-type high-speed bearings, the E-type design offers higher speed capability and can accommodate heavier loads. Combined with a phenolic resin cage and Class B light preload, the bearing achieves a limiting speed of 110,000 r/min.

 

4. Class B Light Preload – Ideal for High-Speed Precision Applications

Class B light preload provides precise 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, significantly improving system rigidity and shaft positioning accuracy. This ensures stable performance even at the 110,000 r/min limiting speed.

 

5. Universal Matchable (GB) – One Inventory, Infinite Arrangements

GB universal matchability delivers outstanding value:

 

Simplified inventory: Stock a single model to cover DB (<>), DF (><), and DT (>>) pairing needs

 

On-site flexibility: Change arrangements during commissioning based on actual load directions

 

Easy maintenance: Replace individual bearings without replacing entire matched sets

 

No shims required: Install directly to achieve design preload

 

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

The P4A tolerance class (superior to ABEC 7) guarantees minimal radial runout and vibration. Bore and outside diameter tolerances are -0.004 mm to 0.

 

7. Extreme Lightweight – Only 19 – 22 Grams

The bearing weighs only 0.019 – 0.022 kg (19 – 22 g) . The extremely low rotating mass effectively reduces centrifugal loads and inertia moments at high speeds.

 

8. Lightweight Phenolic Resin Cage

The lightweight high-strength phenolic resin cage provides excellent guidance accuracy and low friction at high speeds. This material offers an excellent strength-to-weight ratio, contributing to reduced centrifugal forces, friction, and heat generation – a key factor in achieving the 110,000 r/min limiting speed.

 

9. Open Design – Flexible Lubrication Options

This bearing features an open design, allowing flexible selection of lubrication methods based on application – grease lubrication for general ultra-high-speed applications, oil lubrication for extreme ultra-high-speed machining.

 

10. Clear Performance Specifications

 

Parameter Value

Bore d 12 mm

Bore Tolerance -0.004 mm to 0

Outer Diameter D 28 mm

Width B 8 mm

Contact Angle 25°

Dynamic Radial Load 691 lbf (3.07 kN)

Static Radial Load 286 lbf (1.27 kN)

Ball Diameter Dw 3.969 mm

Ceramic Balls per Bearing 12

Limiting Speed 110,000 r/min

Ball Material Silicon Nitride (Si₃N₄)

Ring Material Chrome Steel

Cage Material Phenolic Resin

Seal Type Open

Tolerance Class P4A

Preload Class B (Light)

Arrangement Universal Matchable (SU)

Weight 0.019 – 0.022 kg (19 – 22 g)

Temperature Range -30°C to 110°C

Typical Applications

The NMT 7001 ACEGB/HCP4A, with its 25° contact angle high axial rigidity, hybrid ceramic ultra-high-speed performance, and universal matchable flexibility, covers an exceptionally wide range of high-end miniature applications:

 

Machine Tool Spindles – CNC machine tools, precision grinders

 

High-Speed Machinery – PCB drilling machines, engraving machines

 

Aerospace Components – gyroscopes, actuators, jet engine parts

 

Medical Equipment – high-speed dental handpieces, surgical tools, medical imaging devices

 

Semiconductor Manufacturing – precision wafer processing spindles

 

High-Frequency Motors – high-speed, high-precision miniature motors

 

Industrial Robots – micro high-speed rotary joints

 

Precision Instruments – measuring devices, optical scanners

 

Important Installation Notes

✅ This bearing is universally matchable (GB) – any two bearings of the same model can be directly paired. Configurable as back-to-back (<>), face-to-face (><), or tandem (>>) arrangements.

 

✅ This bearing features an open design – select appropriate lubrication method based on application. To achieve the 110,000 r/min limiting speed, oil-air or oil-mist lubrication is recommended.

 

✅ For paired installations, using bearings from the same production batch is recommended for optimal consistency.

 

⚠️ This bearing comes with factory-preset Class B light 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).

 

⚠️ A single-row angular contact ball bearing can accommodate axial load in one direction only. Paired installations (DB/DF/DT) are required for bidirectional axial load capacity.

 

⚠️ Ensure the contact angle direction matches the intended load direction – incorrect orientation will eliminate load capacity.

 

⚠️ Hybrid ceramic bearings are more sensitive to installation shock. Heat mounting or hydraulic installation methods are recommended – avoid impact on raceways or rolling elements.

 

✅ Installation in a clean environment is recommended to prevent contaminant ingress that could affect ultra-high-speed performance.

 

NMT Quality Commitment

Japan NMT (Enmutī) has deep expertise in the precision bearing industry, with breakthroughs in material purification, process refinement, scenario customization, and intelligent upgrading, transforming precision bearings into core solutions addressing pain points across multiple industries. The NMT 7001 ACEGB/HCP4A bearing is manufactured to strict Japanese quality standards – from ring material (high-purity chrome steel), ceramic balls (HIP silicon nitride), to superfinishing processes. End-face height difference, parallelism, and contact angle deviation of each bearing are tightly controlled to ensure universal matchability consistency across any two bearings of the same model. The combination of 25° contact angle (AC type), high-speed E-type design, hybrid ceramic technology (HC), P4A precision, Class B light preload, and universal matchable flexibility makes this bearing the flagship miniature precision bearing in the NMT 7001 series – offering the perfect balance of high axial rigidity, ultra-high speed, and flexible arrangement.

 

Choose NMT 7001 ACEGB/HCP4A for:

 

✅ 25° contact angle – high axial rigidity and load capacity

 

✅ Hybrid ceramic technology – 110,000 r/min ultra-high-speed performance

 

✅ E-type high-speed design – ultra-high speed and heavy load combined

 

✅ Universal matchable – one inventory, infinite arrangements

 

✅ Class B light preload – ideal for high-speed precision applications

 

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

 

✅ Extreme lightweight – only 19 – 22 g

 

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

 

✅ Open design – flexible lubrication options