Product Overview

The NMT 71901 CEGB/P4A is a sealed, universally matchable single-row super-precision angular contact ball bearing. With a 12 mm bore, 24 mm outer diameter, and 6 mm width, this bearing is the ultra-compact member of the 719 series. Featuring a 15° contact angle (CE type) and high-speed E-type design, combined with all-steel rolling elements and a phenolic resin cage, factory-preset with Class B light preload (GB) , and equipped with non-contact rubber seals on both sides, it integrates ultra-high-speed performance, maintenance-free sealing, extreme lightweight, and flexible arrangement capability into a single package, accommodating radial and unidirectional axial loads simultaneously.

 

The bearing offers a radial dynamic load rating of 2.16 kN (486 lbf) and a static load rating of 0.88 kN (198 lbf) . The GB universal matchable suffix indicates that this bearing features universal matchable (SU) capability – any two bearings of the same model can be directly paired without selective shimming or additional grinding, and can be freely configured in back-to-back (<>), face-to-face (><), or tandem (>>) arrangements. Manufactured to the P4A super-precision tolerance class with a 15° contact angle and Class B light preload, the bearing achieves a limiting speed of 109,000 r/min under grease lubrication and 165,000 r/min under oil-air lubrication. The bearing weighs only 0.01 kg (10 g) with an operating temperature range of -30°C to 110°C.

 

Model Code Decoding – Understanding NMT 71901 CEGB/P4A

Code Meaning

71901 Basic series designation, 12 mm bore, 24 mm OD, 6 mm width

CE 15° contact angle + High-speed E-type design – 15° small contact angle offers extremely high limiting speed potential and minimal heat generation; E-type optimizes internal geometry for higher speed capability

G Single bearing (not a pre-assembled set)

B Class B light preload – eliminates internal clearance, improves system stiffness

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

Seals Non-contact rubber seals on both sides

Core Value: GB universal matchability (SU) means every NMT 71901 CEGB/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 selection or re-grinding. The CE-type 15° contact angle + E-type high-speed design generates minimal frictional heat at equivalent speeds, offering extremely high limiting speed potential (oil-air lubrication 165,000 r/min). P4A super-precision ensures bore and OD tolerances are controlled within -0.004 mm to 0. The non-contact seals effectively prevent contaminant ingress, extending bearing service life – these four elements work together to make this bearing the ultimate precision bearing solution for miniature ultra-high-speed 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. This ensures stable temperature performance even at 165,000 r/min ultra-high speeds, while significantly extending maintenance intervals.

 

2. 165,000 r/min Ultra-High Speed – Industry-Leading Performance

This bearing achieves a limiting speed of 165,000 r/min under oil-air lubrication and 109,000 r/min under grease lubrication. This speed level makes it the ideal choice for ultra-high-speed miniature spindles in PCB drilling machines, dental handpieces, and high-speed engraving machines. The synergy between the 15° contact angle and E-type high-speed design ensures stable operation and low heat generation at extreme speeds.

 

3. 15° Contact Angle (CE Type) + High-Speed E-Type Design – The Perfect Union of Ultra-High-Speed Performance

The 15° small contact angle generates less frictional heat at equivalent speeds, offering higher limiting speed potential than 25° designs. The E-type high-speed design optimizes internal geometry and rolling element parameters – ball diameter 3.175 mm, 12 balls per bearing – significantly reducing sliding friction and churning losses at high speeds.

 

4. 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

 

5. 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. This ensures stable temperature performance even at the 165,000 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, meeting stringent surface quality and dimensional consistency requirements.

 

7. Extreme Lightweight – Only 10 Grams

The bearing weighs only 0.01 kg (10 g) with a carbon footprint of just 0.04 kg CO₂e. The extremely low rotating mass effectively reduces centrifugal loads and inertia moments at high speeds, making it the ideal choice for miniaturized, lightweight designs.

 

8. Lightweight Phenolic Resin Cage

The lightweight high-strength phenolic resin cage provides excellent guidance accuracy and low friction at ultra-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 165,000 r/min limiting speed.

 

9. Clear Performance Specifications

 

Parameter Value

Bore d 12 mm

Bore Tolerance -0.004 mm to 0

Outer Diameter D 24 mm

OD Tolerance -0.004 mm to 0

Width B 6 mm

Contact Angle 15°

Dynamic Radial Load 2.16 kN (486 lbf)

Static Radial Load 0.88 kN (198 lbf)

Ball Diameter Dw 3.175 mm

Balls per Bearing 12

Speed (Grease) 109,000 r/min

Speed (Oil-Air) 165,000 r/min

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 B (Light)

Arrangement Universal Matchable (SU)

Weight 0.01 kg (10 g)

Temperature Range -30°C to 110°C

Typical Applications

The NMT 71901 CEGB/P4A, with its sealed protection, 165,000 r/min ultra-high speed, and universal matchable flexibility, covers an exceptionally wide range of cutting-edge miniature ultra-high-speed applications:

 

PCB Drilling Machine Spindles – high-speed micro-hole drilling for printed circuit boards

 

Dental Handpieces – high-speed dental turbine handpieces

 

High-Speed Engraving/Milling Machines – micro-precision mold and jewelry processing

 

Micro-Machining Electric Spindles – micro-milling, micro-drilling

 

Optical Scanning Devices – high-speed rotating mirrors, laser scanning

 

Medical Surgical Power Tools – high-speed orthopedic drills, micro-surgical instruments

 

Semiconductor Manufacturing Equipment – wafer dicing, chip packaging

 

Aerospace Micro-Components – gyroscopes, micro-actuators

 

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 non-contact seals and comes pre-lubricated from the factory – 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 165,000 r/min limiting speed, oil-air lubrication is strongly recommended; grease lubrication limits speed to 109,000 r/min.

 

⚠️ 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.

 

⚠️ Due to the extremely small size (only 10 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) applies strict Japanese quality standards to every 71901 CEGB/P4A bearing – 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 15° contact angle (CE type), E-type high-speed design, P4A precision, Class B light preload, non-contact seals, and universal matchable flexibility makes this bearing the flagship miniature precision bearing in the NMT 719 series – offering the perfect balance of ultra-high speed, maintenance-free operation, and flexible arrangement.

 

Choose NMT 71901 CEGB/P4A for:

 

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

 

✅ 165,000 r/min oil-air lubrication limiting speed – industry-leading

 

✅ 15° contact angle + E-type high-speed design – ultra-high speed and low heat 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 10 g

 

✅ Lightweight phenolic resin cage – low friction, low noise, high speed

 

✅ Factory pre-lubricated – ready to install