Product Overview

The NMT 7010 ACD/P4ADT is a pre-assembled duplex tandem matched super-precision all-steel angular contact ball bearing set, comprising 2 rows of bearings precision-paired in a tandem (<<) configuration. With a total width of 32 mm (16 mm per row × 2), a 50 mm bore, and an 80 mm outer diameter, this set features a 25° contact angle (AC type) and D-type high-capacity design, with all-steel rolling elements and a lightweight phenolic resin cage, specifically optimized for high-speed rotational applications dominated by heavy unidirectional axial loads.

 

The bearing set offers a basic dynamic load rating of 46.2 kN and a static load rating of 46.5 kN – more than double the capacity of a single-row bearing. The tandem arrangement doubles unidirectional axial load capacity by stacking the axial force capability of both rows. The P4A super-precision tolerance class ensures micron-level rotational accuracy at high speeds, with limiting speeds reaching 46,000 r/min under oil-air lubrication and 12,000 - 17,000 r/min under grease lubrication.

 

Model Code Decoding – Understanding NMT 7010 ACD/P4ADT

Code Meaning

7010 Basic series designation, 50 mm bore, 80 mm OD, 32 mm total width

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

D Tandem (DT) arrangement – 2 bearings mounted in the same direction (<<)

P4A Super-precision tolerance class – dimensional accuracy to ISO P4 class, running accuracy superior to P4

DT Duplex Tandem – 2 bearings mounted in the same direction (<<) , factory end-face matched

Critical Feature: The DT tandem arrangement means both bearings share the same contact angle orientation. Axial loads are shared equally across both rows, enabling extreme unidirectional thrust capacity. This matched set does not have a preset internal preload. Actual operating preload must be adjusted during installation via locknut torque or spacer selection. This is a non-universal matchable fixed set – the 2 bearings are factory end-face matched and must not be interchanged or mixed with other bearings.

 

Core Performance Advantages

1. Tandem Arrangement – Doubled Unidirectional Axial Capacity

With both rows oriented identically, axial load capacity increases by nearly 100% compared to a single bearing. The 46.2 kN dynamic rating and 46.5 kN static rating make this set ideal for heavy-cutting lathe spindles, powerful drilling spindles, and other unidirectional thrust applications. Compared to equivalent B and E design high-speed bearings, the D-type design is best suited for heavier loads.

 

2. 25° Contact Angle + 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 ball diameter (9.525 mm) and quantity (18 balls per bearing), achieves outstanding load capacity within a compact 32 mm total width.

 

3. All-Steel Rolling Elements – High Rigidity, Impact Resistance, Cost-Effectiveness

Premium chrome steel rings and balls offer higher fracture toughness and impact resistance than hybrid ceramic versions – more reliable under interrupted cutting and accidental overload conditions. All-steel bearings also offer significant cost advantages.

 

4. Factory Precision Matching – Uniform Load Distribution

Every DT set undergoes end-face matching grinding and preload configuration at the NMT factory, ensuring highly uniform load sharing between the two bearings in tandem installation, preventing individual bearing overload and significantly extending overall set service life.

 

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

The P4A tolerance class guarantees minimal radial runout and axial play. Bore and outside diameter tolerances are -0.004mm to 0, meeting stringent surface quality and dimensional consistency requirements. Operating temperature range is -30°C to 110°C.

 

6. Lightweight Phenolic Resin Cage

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 46,000 r/min limiting speed.

 

7. Clear Performance Specifications

 

Parameter Value

Bore d 50 mm

Outer Diameter D 80 mm

Total Width B 32 mm (2×16 mm)

Contact Angle α 25°

Dynamic Load Rating C 46.2 – 46.5 kN

Static Load Rating C₀ 46.5 – 48 kN

Fatigue Load Limit Pu 1.96 kN

Speed (Oil-Air) 46,000 r/min

Speed (Grease) 12,000 – 17,000 r/min

Ball Diameter Dw 9.525 mm

Balls per Bearing 18

Ball Material Chrome Steel

Ring Material Chrome Steel

Cage Material Phenolic

Tolerance Class P4A

Arrangement Tandem (<<) DT

Bearings in Set 2

Weight 0.498 – 0.51 kg

Carbon Footprint 1.8 kg CO₂e

Temperature Range -30°C to 110°C

Typical Applications

The NMT 7010 ACD/P4ADT is ideally suited for high-speed precision equipment where unidirectional axial loads dominate:

 

CNC Lathe Spindles – sustaining continuous axial cutting feed forces

 

Vertical/Horizontal Machining Centers – heavy milling spindles (fixed axial direction)

 

Deep-Hole Drilling Spindles – high-thrust drilling and gun-drilling applications

 

Grinding Machine Wheel Spindles – high-speed rotation under unidirectional grinding forces

 

High-Speed Electric Spindles – precision machining units with constant axial load direction

 

Industrial Pumps/Compressors – unidirectional thrust positioning in high-speed rotating shafts

 

High-Frequency Motors – applications requiring high rigidity and high speed

 

Turbomachinery – high-speed turbine rotor axial positioning

 

Important Installation Notes

⚠️ This is a non-universal matched fixed set (DT)  – the 2 bearings are supplied as one complete unit. Do not interchange or mix with other bearings of the same model.

 

⚠️ The tandem arrangement (<<) is directional. Ensure the contact angle direction points toward the incoming axial load – incorrect orientation will eliminate load capacity.

 

⚠️ This set does not have a preset internal preload. Actual preload must be controlled during installation via locknut torque or precision spacers. Strictly follow NMT's installation guidelines and recommended torque values.

 

⚠️ To achieve the 46,000 r/min limiting speed, oil-air lubrication is strongly recommended. Grease lubrication limits speed to approximately 12,000 – 17,000 r/min.

 

⚠️ Ensure shaft and housing fits comply with P4A grade requirements (bore/OD tolerance -0.004mm to 0) to achieve the expected rotational accuracy and service life.

 

NMT Quality Commitment

Japan NMT (Enmutī) applies stringent end-face parallelism and height-difference matching grinding to every DT tandem set, ensuring load-sharing deviation between the two rows is minimized to an extremely small range. The 7010 ACD/P4ADT delivers P4A accuracy, D-type high-capacity design, all-steel rigidity, and tandem-doubled axial capability for long-lasting, stable rotational support in your heavy-duty unidirectional-load high-speed spindles.

 

Choose NMT 7010 ACD/P4ADT for:

 

✅ Tandem arrangement – doubled unidirectional axial capacity

 

✅ 25° contact angle + D-type high capacity – powerful combined load capability

 

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

 

✅ P4A super-precision running accuracy

 

✅ Factory precision matched – uniform load distribution

 

✅ Open preload adjustment for flexible application tuning

 

✅ Lightweight phenolic resin cage

 

✅ 46,000 r/min ultra-high-speed performance