1 Complete Model, Dimensions, Loads & Technical Parameters

Full Model: 7007 ACD/P4AQGC

Model Code Explanation

7007: Standard boundary dimension of 70 series precision angular contact ball bearing;

ACD: 25° contact angle, high-load D internal profile;

P4A: P4A ultra-precision tolerance class;

QGC: 4-bearing set, universal matching, medium preload specification.

Standard Dimension Parameters

Bore d: 35 mm

Outer diameter D: 62 mm

Width B: 56 mm

Contact angle: 25 °

Performance Data

Basic dynamic load rating Cr: 39.7 kN

Basic static load rating C0r: 36 kN

Speed note: Contact SKF for data on achievable rotational speed.

Full Product Attributes

Contact form: standard two-point contact

Number of bearings: 4 (4 single bearings contained in one set)

Ring structure: integrated inner ring and outer ring

Internal design: high-load D optimized design

Compatible matched arrangement: Yes, back-to-back (<>), face-to-face (><), tandem (>>)

Duplex layout: universal matched set

Quantity of bearings in kit: 4

Preload specification: medium preload

Tolerance class: P4A precision grade

Material: bearing steel

Coating: uncoated

Seal: open type without seals

Pre-filled lubricant: none, lubrication configured on site

Indicative carbon footprint for new product: 2.2 kg CO₂e

Net weight: 0.6 kg

eClass code: 23-05-08-04

UNSPSC code: 31171531

Note: The 25° large contact angle delivers outstanding axial capacity. High-load D raceway enhances load resistance on contact zone. Four universally matched bearings can be reconfigured into various mounting layouts with factory medium preload calibration. Open design requires external dust protection. Do not randomly mix with bearings from other batches to avoid loss of preload accuracy.

2 Structure & Operating Characteristics

Japan NMT 7007 ACD/P4AQGC is a 7007 size 25° high-load D-type 4-piece universally matched precision angular contact bearing set, consisting of four bearing steel single units from identical production batch. Optimized D-shaped raceway improves contact stiffness and load limit; the 25° contact angle balances radial capacity and heavy bidirectional axial cutting thrust.

Open non-sealed design eliminates seal drag and supports high-speed grease and oil-air lubrication systems. No lubricant pre-filled; lubrication filling is implemented during assembly.

All four bearings are sorted for universal matching at factory, allowing flexible recombination for DB, DF and tandem arrangements. Medium preload is preset to balance spindle rigidity and heat generation, suitable for medium speed, medium-to-heavy cutting conditions. The matched accuracy is calibrated as a complete set; mixing with outside single bearings is not recommended.

3 Core Performance Advantages

1. 25° contact angle + high-load D geometry: Strong axial capacity and good resistance against axial impact load.

2. P4A ultra-precision grade: Strict rotary runout control to sustain long-term accuracy of heavy-duty machining spindles.

3. 4-bearing universal matched kit: Flexible assembly layout options for different spindle support requirements.

4. Factory preset medium preload: Minimizes complicated on-site preload calculation and adjustment work.

5. Bearing steel material: High hardness, excellent fatigue and wear resistance for continuous heavy-load machining.

6. Open seal-free construction, compatible with all centralized high-speed lubrication systems.

4 Typical Application Scenarios

4.1 Vertical machining centers & mould machine heavy-duty precision spindles: Spindle units subjected to heavy axial milling and boring loads.

4.2 Large precision cylindrical grinders & CNC tool grinder spindles: Four-point support structure for high-precision heavy-load grinding.

4.3 Heavy-duty CNC lathe and multi-tasking machine spindle modules: Precision rotary supports requiring high rigidity and bidirectional axial load capacity.

5 Assembly Specifications & Usage Guidelines

5.1 Assembly Environment & Operation Standards

P4A high-precision bearing sets must be assembled inside dust-free clean workshops. Remove all burrs and metal debris on shaft and housing mating surfaces. Controlled thermal mounting is preferred; direct impact on bearing rings and raceways is prohibited. Use the complete original four-bearing set where possible; avoid splitting and mixing with bearings from different batches.

5.2 Matching & Preload Instructions

Available layout options:

Back-to-back (<> DB): Excellent overturning moment resistance, suitable for radial offset load;

Face-to-face (>< DF): Better alignment tolerance during installation;

Tandem (>> DT): Supports larger continuous unidirectional axial thrust.

Medium preload is calibrated at factory. Custom precision spacers are required if preload level needs modification.

5.3 Lubrication Matching Solutions

No pre-filled lubricant. Oil-air lubrication is recommended for continuous long-term operation; dedicated high-speed extreme-pressure grease can be adopted for intermittent machining. Do not mix different brands or types of lubricants. Regularly inspect lubrication pipelines.

5.4 Speed Parameter Note

Obtain reference limiting speed data from SKF. Maintain sufficient safety margin under heavy loads; reduce operating speed accordingly to control bearing temperature rise as load increases.

6 Daily Maintenance & Fault Troubleshooting

Carry out multi-stage low-speed progressive running-in after assembly; increase speed to rated level only after temperature and vibration stabilize. Open bearings have no inherent dust resistance; the machine must be equipped with labyrinth or contact dust seals.

Ensure continuous stable lubrication supply to prevent raceway damage from dry friction. When abnormal temperature rise, vibration growth or noise occurs, sequentially check lubrication supply, mounting coaxiality, preload condition and whether actual load exceeds allowable range.