Product Overview

The NMT S7001 ACEGA/P4A is a sealed, universally matchable single-row super-precision 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 all-steel rolling elements and a phenolic resin cage, factory-preset with Class A extra light preload (GA) , and equipped with non-contact rubber seals on both sides. It integrates high axial rigidity, high load capacity, maintenance-free sealing, 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 and Class A extra light preload, the bearing achieves a limiting speed of 95,000 r/min. The bearing weighs only 0.021 – 0.022 kg (21 – 22 g)  with an operating temperature range of -30°C to 110°C. Class A preload force is 28 N with axial stiffness of 34 N/µm.

 

Model Code Decoding – Understanding NMT S7001 ACEGA/P4A

Code Meaning

S Sealed design – equipped with non-contact rubber seals on both sides

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

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

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

Core Value: The S sealed design effectively prevents contaminant ingress, extending bearing service life. GA universal matchability (SU) means every NMT S7001 ACEGA/P4A 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. Class A extra light preload (28 N preload force) eliminates internal clearance and reduces vibration and noise at high speeds. 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. Non-Contact Seals – Maintenance-Free, Extended Life

The bearing features non-contact rubber seals on both sides that effectively prevent contaminants such as cutting fluids and dust from entering the bearing interior, while the non-contact design avoids friction between the seal lip and the inner ring – adding no extra resistance or heat generation. Integral sealing prolongs bearing service life. This ensures stable temperature performance even at 95,000 r/min ultra-high speeds, while significantly extending maintenance intervals.

 

2. 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 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.

 

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 A extra light preload, the bearing achieves a limiting speed of 95,000 r/min.

 

4. Universal Matchable (GA) – One Inventory, Infinite Arrangements

GA 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

 

5. Class A Extra Light Preload – Ideal for High-Speed Precision Applications

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. Preload force is 28 N with axial stiffness of 34 N/µm. This ensures stable temperature performance even at the 95,000 r/min limiting speed.

 

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. Distance to pressure point a = 8.8 mm.

 

7. Extreme Lightweight – Only 21 – 22 Grams

The bearing weighs only 0.021 – 0.022 kg (21 – 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 95,000 r/min limiting speed.

 

9. Factory Pre-Lubricated – Ready to Install

This bearing comes pre-lubricated from the factory with grease – ready to install out of the box without additional lubrication handling, significantly simplifying the assembly process.

 

10. Clear Performance Specifications

 

Parameter Value

Bore d 12 mm

Bore Tolerance -0.004 mm to 0

Outer Diameter D 28 mm

OD Tolerance -0.004 mm to 0

Width B 8 mm

Contact Angle 25°

Dynamic Radial Load 691 lbf (3.07 kN)

Static Radial Load 286 lbf (1.27 kN)

Fatigue Load Limit Pu 0.054 kN

Ball Diameter Dw 3.969 mm

Balls per Bearing 12

Limiting Speed 95,000 r/min

Distance to Pressure Point a 8.8 mm

Preload Force (Class A) 28 N

Axial Stiffness (Class A) 34 N/µm

Ball Material Chrome Steel

Ring Material Chrome Steel

Cage Material Phenolic Resin

Seal Type Non-Contact Rubber Seals (both sides)

Tolerance Class P4A

Preload Class A (Extra Light)

Arrangement Universal Matchable (SU)

Weight 0.021 – 0.022 kg (21 – 22 g)

Temperature Range -30°C to 110°C

Typical Applications

The NMT S7001 ACEGA/P4A, with its sealed protection, 25° contact angle high axial rigidity, E-type high-speed design, 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 (GA) – 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 non-contact seals and comes pre-lubricated from the factory with grease – ready to install out of the box.

 

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

 

✅ To achieve the 95,000 r/min limiting speed, oil-air or oil-mist lubrication is recommended【6†L6-L7注】; grease lubrication limits speed to 95,000 r/min.

 

⚠️ This bearing comes with factory-preset Class A extra light preload (28 N preload force). 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.

 

⚠️ Due to the compact size (only 21 – 22 g), extra care is required during installation to avoid excessive force.

 

✅ 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 S7001 ACEGA/P4A bearing is manufactured to strict Japanese quality standards – from ring material (high-purity chrome steel) and rolling elements 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 non-contact seals (S), 25° contact angle (AC type), high-speed E-type design, P4A precision, Class A extra 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, maintenance-free operation, and flexible arrangement.

 

Choose NMT S7001 ACEGA/P4A for:

 

✅ Non-contact seals – maintenance-free, extended life

 

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

 

✅ E-type high-speed design – 95,000 r/min ultra-high-speed performance

 

✅ Universal matchable – one inventory, infinite arrangements

 

✅ Class A extra light preload – 28 N preload force / 34 N/µm axial stiffness

 

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

 

✅ Extreme lightweight – only 21 – 22 g

 

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

 

✅ Factory pre-lubricated – ready to install