
SKF 3311 ATN9 double row angular contact ball bearing
- Brand
- SKF
- Category
- Bearings
- Subcategory
- Double row angular contact ball bearings
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How to read SKF 3311 ATN9
- 33Series
- Double row angular contact ball bearings, 33 series. For the same bore, each series has a different outside diameter and width.
- 11Bore
- 55 mm bore: 11 × 5.
- ATN9Suffix
- SKF suffix: it defines the variant (sealing, cage, internal clearance or other features).
3311 is the standard (ISO) basic designation: it defines the type, the series and the bore.
Description
The SKF 3311 ATN9 bearing has a 55 mm bore, a 120 mm outside diameter and a 49.2 mm width (55 x 120 x 49.2 mm).
SKF 3311 ATN9 is a reference of double row angular contact ball bearing, within Bearings. Request a quote for 3311 ATN9 via WhatsApp or email with the quantity you need; we respond promptly with the quote and equivalents.
SKF double row angular contact bearings are components designed to support combined radial and axial loads in both directions. Their design with two rows of balls with opposite contact angles allows high axial load capacity and greater rigidity than single row bearings. They are used in applications where precision and the ability to support forces in two directions are required, such as machine tool spindles, pumps and compressors. MR Accesorios Industriales sells this line as part of its broad catalog of SKF bearings.
The designation of these bearings follows a scheme that combines numbers and suffixes. For example, in 3200 ATN9, the first digits indicate the size and series; the suffix ATN9 indicates specific design characteristics, such as the contact angle and the cage type. In the 3200 series, the first two digits (32) identify the dimension series, while the following two (00, 01, 02, etc.) indicate the size. The ATN9 suffix is common in this family and provides information about the internal execution. To correctly interpret each code, it is essential to consult the SKF product tables, but in general, these bearings are designated with the 32 series and suffixes that reflect manufacturing particularities.
These bearings are used in a variety of industries in Argentina, including metalworking, food, petrochemical and power generation. They are common in equipment such as centrifugal pumps, screw compressors, industrial fans, machine tool spindles and transmission boxes. Their ability to support axial loads in both directions makes them ideal for applications where high precision and rigidity are required, such as in boring machines and milling machines. They are also used in the automotive industry, although to a lesser extent, in components such as steering boxes and transmission shafts.
To select the right bearing, it is crucial to consider the magnitude and direction of the loads, the rotation speed, the lubrication conditions and the working environment. These bearings usually come with standard internal clearance, but may require specific adjustment depending on the application. Mounting must be carried out carefully, ensuring correct alignment to avoid additional loads. Lubrication can be with grease or oil, depending on speed and temperature. In applications with contaminants, it is recommended to use additional seals or shields. It is important to follow the manufacturer's recommendations for mounting and lubrication, since incorrect mounting can significantly reduce the service life of the bearing.
As for equivalents and interchangeability, SKF double row angular contact bearings can be replaced by products from other manufacturers that follow the same dimensions and specifications. However, it is essential to verify tolerances and internal clearance, since they may vary between brands. Suffixes such as ATN9 may have equivalents in other nomenclatures, but direct interchangeability should not be assumed without consulting the technical data sheets. At MR Accesorios Industriales, we can advise you on the corresponding options and compatibilities, always based on the technical specifications of each product.
If you need a quote for SKF double row angular contact bearings, or if you have questions about the designation or the application, do not hesitate to contact us. At MR Accesorios Industriales we distribute industrial components and we can help you find the right solution. Send us the code of the bearing you need on WhatsApp and we will reply shortly with the information you require.
Dimensions
Boundary dimensions of the basic designation 3311 per ISO 15: 55 x 120 x 49.2 mm (d x D x B).
- Bore
- 55mm
- Outside diameter (D)
- 120mm
- Width (B)
- 49.2mm
Frequently Asked Questions
- What are the dimensions of the SKF 3311 ATN9 bearing?
- The SKF 3311 ATN9 bearing has a 55 mm bore, a 120 mm outside diameter and a 49.2 mm width (55 x 120 x 49.2 mm). These are the standardised boundary dimensions (ISO 15) of the basic designation 3311.
- What does the ATN9 suffix mean on an SKF bearing?
- The ATN9 suffix indicates specific internal design characteristics, such as the contact angle and the cage type. In the 3200 series, this suffix is common and may imply a polyamide cage and a 25 degree contact angle. For precise details, consult the product data sheet.
- Do these bearings support axial loads in both directions?
- Yes, double row angular contact bearings are designed with two rows of balls with opposite contact angles, which allows them to support axial loads in both directions, in addition to radial loads. This makes them suitable for applications with combined loads.
- How are these bearings correctly mounted?
- Mounting must ensure precise alignment and avoid impacts that could damage the raceways. It is recommended to use suitable tools and follow the manufacturer's instructions. Lubrication and adjustment of internal clearance are critical for optimal operation. If in doubt, consult a specialist.

