SKF 618-9 9x17x4 Deep Groove Ball Bearing

SKF 618/9 is an open, single-row deep groove ball bearing with compact dimensions of 9x17x4 mm. It belongs to the SKF 618 dimension series and combines a 9 mm bore, 17 mm outside diameter and only 4 mm width. SKF specifies a dynamic load rating C of 0.871 kN, static load rating C0 of 0.34 kN, reference speed of 85,000 rpm and limiting speed of 53,000 rpm.

SKF 618/9 Technical Specification

Manufacturer: SKF

Designation: 618/9

Bearing type: Deep groove ball bearing

Design: Single row

Configuration: Open

Bore type: Cylindrical

Bore diameter d: 9 mm

Outside diameter D: 17 mm

Width B: 4 mm

Dimensions: 9x17x4 mm

Dynamic load rating C: 0.871 kN

Static load rating C0: 0.34 kN

Fatigue load limit Pu: 0.014 kN

Reference speed: 85,000 rpm

Limiting speed: 53,000 rpm

Catalogue mass: approx. 0.0034 kg

SKF 618/9 Dimensions

The principal dimensions are:

d = 9 mm - bore diameter

D = 17 mm - outside diameter

B = 4 mm - bearing width

Complete dimensions:

9x17x4 mm

The combination of a 17 mm outside diameter and only 4 mm width gives SKF 618/9 a particularly compact cross-section.

All three dimensions should be checked when selecting the bearing for an existing installation.

What Is SKF 618/9?

SKF 618/9 belongs to the family of:

single-row deep groove ball bearings

Deep groove ball bearings use deep raceway grooves in the inner and outer rings with balls positioned between the raceways.

This construction is primarily intended to accommodate radial loads and can also accommodate axial loads in both directions within the operating limits of the bearing arrangement.

The exact SKF designation for this bearing is:

618/9

SKF 618 Series

SKF 618/9 belongs to the:

618 dimension series

This series is characterized by a relatively small radial cross-section compared with many other deep groove ball bearing series.

For SKF 618/9:

Bore diameter: 9 mm

Outside diameter: 17 mm

Width: 4 mm

The compact geometry can be useful where installation space is restricted, provided the bearing's load capacity and other operating parameters meet the requirements of the application.

Open Bearing Design

SKF 618/9 is an:

open bearing

The basic designation does not specify integral contact seals or metal shields.

This distinction is important when selecting the bearing because an open bearing arrangement may require external protection and an appropriate lubrication system depending on the machine design and operating environment.

Sealed or shielded bearings should not be assumed to have the same width or operating characteristics solely because their bore diameter is also 9 mm.

Dynamic Load Rating

SKF specifies a basic dynamic load rating C of:

0.871 kN

or:

871 N

The dynamic load rating is a catalogue parameter used in bearing life calculations.

It should not be interpreted as a simple maximum permissible operating load without considering bearing life, speed, lubrication and the complete operating conditions.

Static Load Rating

The basic static load rating C0 is:

0.34 kN

or:

340 N

SKF also specifies a fatigue load limit Pu of:

0.014 kN

or:

14 N

These values relate specifically to the SKF 618/9 configuration and should not be replaced with load ratings from a dimensionally similar bearing produced by another manufacturer.

What Loads Can SKF 618/9 Carry?

As a single-row deep groove ball bearing, SKF 618/9 is primarily designed for:

radial loads

Its raceway geometry also enables it to accommodate:

axial loads in both directions

within the limits of the bearing and the complete arrangement.

For a specific application, the magnitude and direction of the load should be evaluated together with the required bearing life and operating speed.

SKF 618/9 Reference Speed

SKF specifies a reference speed of:

85,000 rpm

The reference speed is a thermal reference value used in the assessment of bearing operating conditions.

It should not be confused with the limiting speed.

SKF 618/9 Limiting Speed

The SKF catalogue specifies a limiting speed of:

53,000 rpm

Reference speed:

85,000 rpm

Limiting speed:

53,000 rpm

These values describe different technical criteria and should not be used interchangeably.

The actual permissible operating speed depends on the complete application, including load, lubrication, temperature, fits and operating conditions.

Compact 9x17x4 mm Design

One of the most distinctive characteristics of SKF 618/9 is its small dimensional envelope:

9 mm bore

17 mm outside diameter

4 mm width

The radial difference between the bore and outside diameter is only 8 mm.

This makes the bearing particularly compact, but the small dimensions also mean that its load ratings must be carefully considered during bearing selection.

SKF 618/9 vs Other 9 mm Bearings

A 9 mm bore alone does not identify the correct bearing.

Other bearings with a 9 mm bore can have different:

outside diameters

widths

load ratings

sealing configurations

internal designs

speed capabilities

For SKF 618/9, the complete dimensional identification is:

9x17x4 mm

SKF 618/9 vs 628/9

SKF 618/9 should not be confused with:

SKF 628/9

The two bearings have the same:

9 mm bore

and:

17 mm outside diameter

but differ in width and construction.

SKF 618/9:

9x17x4 mm

SKF 628/9:

9x17x5 mm

The additional 1 mm of width is technically significant.

A 628/9 therefore should not be selected as a replacement for 618/9 without checking the available installation space and complete technical requirements.

Is 689 an Equivalent Designation for 618/9?

The designation:

689

is used by some bearing manufacturers for a deep groove ball bearing with nominal dimensions of:

9x17x4 mm

The exact SKF designation for the product described on this page is:

618/9

Matching dimensions can help identify possible alternatives, but dimensional equivalence alone does not confirm complete technical interchangeability.

Load ratings, tolerances, internal clearance, cage construction and operating requirements should also be compared.

How to Select SKF 618/9

Before ordering, verify:

Manufacturer - SKF

Designation - 618/9

Bearing type - deep groove ball bearing

Bore diameter d - 9 mm

Outside diameter D - 17 mm

Width B - 4 mm

Open configuration

Required load capacity

Operating speed

Lubrication

Shaft and housing fits

Operating environment

For replacement applications, the complete manufacturer designation should be checked whenever possible.

Can Another 9x17x4 Bearing Replace SKF 618/9?

Not automatically.

Another bearing may share the same:

9x17x4 mm

dimensions while differing in:

manufacturer specification

load ratings

internal clearance

cage design

material

precision

speed capability

lubrication requirements

For critical applications, the complete technical specification should therefore be compared before substitution.

SKF 618/9 Full Technical Data

Manufacturer: SKF

Designation: 618/9

Product type: Deep groove ball bearing

Rows: Single row

Configuration: Open

Bore: Cylindrical

d: 9 mm

D: 17 mm

B: 4 mm

Dimensions: 9x17x4 mm

Dynamic load rating C: 0.871 kN

Static load rating C0: 0.34 kN

Fatigue load limit Pu: 0.014 kN

Reference speed: 85,000 rpm

Limiting speed: 53,000 rpm

Mass: approx. 3.4 g

FAQ - SKF 618/9

What are the dimensions of SKF 618/9?

SKF 618/9 has a 9 mm bore diameter, 17 mm outside diameter and 4 mm width. Its complete dimensions are 9x17x4 mm.

What type of bearing is SKF 618/9?

It is a single-row deep groove ball bearing.

Is SKF 618/9 an open bearing?

Yes. The basic SKF 618/9 designation identifies the open configuration.

What is the dynamic load rating of SKF 618/9?

SKF specifies a basic dynamic load rating C of 0.871 kN.

What is the static load rating of SKF 618/9?

The basic static load rating C0 is 0.34 kN.

What is the limiting speed of SKF 618/9?

The SKF catalogue specifies a limiting speed of 53,000 rpm and a reference speed of 85,000 rpm.

Are SKF 618/9 and 628/9 the same size?

No. SKF 618/9 measures 9x17x4 mm, while 628/9 has a width of 5 mm. They should not be treated as dimensionally identical.

Is a 689 bearing the same as SKF 618/9?

Some manufacturers use 689 for the 9x17x4 mm bearing size. However, dimensional equivalence alone does not establish complete technical interchangeability with SKF 618/9.

AI Overview

SKF 618/9 is an open, single-row deep groove ball bearing with compact dimensions of 9x17x4 mm. SKF specifies a dynamic load rating C of 0.871 kN, static load rating C0 of 0.34 kN, reference speed of 85,000 rpm and limiting speed of 53,000 rpm. Catalogue mass is approximately 3.4 g.