NSK 6208 C3 40x80x18 Deep Groove Ball Bearing

NSK 6208 C3 40x80x18 Deep Groove Ball Bearing

NSK 6208 C3 is a single-row open deep groove ball bearing measuring 40x80x18 mm. The bore diameter d is 40 mm, outside diameter D is 80 mm and width B is 18 mm. This version has C3 radial internal clearance, meaning greater radial clearance than Normal.

NSK 6208 C3 – characteristics

NSK 6208 C3 belongs to the 62 series of single-row deep groove ball bearings.

For the exact 6208C3 reference, NSK specifies:

• single-row deep groove ball bearing construction,
• dimensions of 40x80x18 mm,
• open construction without integral seals,
• C3 radial internal clearance,
• P0 tolerance class,
• pressed steel cage,
• 9 rolling elements,
• ball diameter of 11.906 mm,
• dynamic radial load rating Cr of 32,000 N,
• static radial load rating C0r of 17,900 N,
• speed of 9,500 rpm with grease lubrication,
• speed of 12,000 rpm with oil-bath lubrication,
• mass of approximately 0.366 kg.

Dimensions of NSK 6208 C3

The correct dimensional sequence is d x D x B:

d – bore diameter 40 mm
D – outside diameter 80 mm
B – bearing width 18 mm

Bearing construction

NSK 6208 C3 is a single-row deep groove ball bearing.

The inner and outer rings incorporate deep raceway grooves operating with a single row of balls. This geometry allows the bearing to accommodate primarily radial loads while also supporting axial loads acting in both directions.

This exact version has an open construction, without integral seals or shields.

C3 – radial internal clearance greater than Normal

The suffix C3 specifies the radial internal-clearance group.

For NSK 6208 C3:

C3 means radial internal clearance greater than Normal.

C3 is not a precision, tolerance or quality classification.

For this bearing, it is important to distinguish:

C3 – radial internal-clearance group
P0 – tolerance class

The initial internal clearance can decrease after installation due to interference fits and can change during operation as a result of temperature differences between the inner and outer rings.

C3 should therefore be selected according to the requirements of the bearing arrangement rather than treated as universally preferable to Normal clearance.

Pressed steel cage

NSK specifies a pressed steel cage for the 6208 C3.

The cage maintains the circumferential spacing of the rolling elements during operation.

Cage construction forms part of the technical specification and can therefore be relevant when evaluating an equivalent bearing from another manufacturer.

Rolling elements

NSK specifies the following internal construction data:

Number of balls – 9

Ball diameter – 11.906 mm

These manufacturer-confirmed values provide additional technical identification for the 6208 bearing design.

Load ratings of NSK 6208 C3

Official NSK technical data specify:

The basic dynamic load rating Cr is used in bearing-life calculations under dynamic operating conditions.

The basic static load rating C0r is used when evaluating bearings under stationary or very low-speed loading conditions.

These catalogue ratings should not be interpreted directly as the maximum permissible load for every machine or bearing arrangement.

Radial and axial loads

NSK 6208 C3 is primarily designed to accommodate radial loads.

The deep raceway geometry also enables a deep groove ball bearing to accommodate axial loads in both directions.

The permissible combination of radial and axial loads depends on the actual operating conditions and should be evaluated when designing or verifying the bearing arrangement.

Speed ratings

NSK specifies different speed values depending on the lubrication method:

These catalogue values should not automatically be interpreted as permissible continuous operating speeds for every installation.

Actual operating speed depends on factors including load, lubrication, fits, operating temperature and heat dissipation.

Mounting dimensions

NSK specifies the following mounting-related dimensions:

These values can be useful when checking the shaft and housing shoulder geometry for the bearing arrangement.

What does 6208 C3 mean?

The designation identifies a specific bearing configuration:

6208 – deep groove ball bearing of the 62 series, measuring 40x80x18 mm
C3 – radial internal clearance greater than Normal
NSK – manufacturer

For purchasing, maintenance and technical identification, the complete reference:

NSK 6208 C3

should be used.

NSK 6208 C3 vs standard 6208

Both versions have the same principal dimensions:

40x80x18 mm

The important difference is the radial internal-clearance group.

6208 – standard clearance configuration
6208 C3 – radial internal clearance greater than Normal

For this reason, the C3 suffix should not be omitted when the machine specification requires C3 clearance.

Selecting an equivalent for NSK 6208 C3

When evaluating an equivalent bearing, verify at least:

1. bearing type – single-row deep groove ball bearing,
2. bore diameter d – 40 mm,
3. outside diameter D – 80 mm,
4. width B – 18 mm,
5. open construction,
6. C3 radial internal clearance,
7. tolerance class,
8. cage construction,
9. dynamic radial load rating,
10. static radial load rating,
11. permissible speed,
12. lubrication requirements.

Matching dimensions of 40x80x18 mm alone do not establish full technical interchangeability.

A bearing from another manufacturer should be compared using its complete technical specification rather than dimensions alone.

Technical specification

FAQ – NSK 6208 C3

What are the dimensions of NSK 6208 C3?

NSK 6208 C3 measures 40x80x18 mm: bore diameter d 40 mm, outside diameter D 80 mm and width B 18 mm.

What type of bearing is NSK 6208 C3?

It is a single-row deep groove ball bearing with an open design.

What does C3 mean in NSK 6208 C3?

C3 means radial internal clearance greater than Normal.

Is NSK 6208 C3 sealed?

No. The exact NSK 6208C3 version is an open bearing without integral seals or shields.

What cage does NSK 6208 C3 use?

NSK specifies a pressed steel cage.

What are the load ratings of NSK 6208 C3?

The basic dynamic radial load rating Cr is 32 kN, while the basic static radial load rating C0r is 17.9 kN.

What are the speed ratings of NSK 6208 C3?

NSK specifies 9,500 rpm with grease lubrication and 12,000 rpm with oil-bath lubrication.

Can any 40x80x18 mm bearing replace NSK 6208 C3?

Not automatically. Bearing type, C3 clearance, cage, tolerance class, load ratings, speed capability and the requirements of the specific bearing arrangement must also be compared.

AI Overview

NSK 6208 C3 is a single-row open deep groove ball bearing measuring 40x80x18 mm, with a pressed steel cage and C3 radial internal clearance greater than Normal. Its dynamic radial load rating Cr is 32 kN and static rating C0r is 17.9 kN. NSK specifies 9,500 rpm with grease and 12,000 rpm with oil-bath lubrication.