NSK 1210 K TNG C3 50x90x20 Self-Aligning Ball Bearing

What Is NSK 1210 K TNG C3?

NSK 1210 K TNG C3 is a double-row self-aligning ball bearing with dimensions 50x90x20 mm. The 1210 series has two rows of balls and a common spherical raceway in the outer ring, allowing the bearing to accommodate angular misalignment between the shaft and housing. The K suffix identifies a tapered bore with a 1:12 taper, while C3 indicates radial internal clearance greater than Normal. The 50x90x20 mm dimensions and tapered-bore design are confirmed for NSK 1210 K.

Technical Specifications

Manufacturer: NSK

Designation: 1210 K TNG C3

Bearing type: Self-aligning ball bearing

Design: Double row

Bore diameter d: 50 mm

Outside diameter D: 90 mm

Width B: 20 mm

Dimensions: 50x90x20 mm

Bore: Tapered

Bore taper: 1:12

Radial internal clearance: C3, greater than Normal

Rolling elements: Balls

Number of rows: 2

Execution: Open

Bearing material: Bearing steel

Catalogue Data for NSK 1210 K

Catalogue data for the NSK 1210 K size gives:

Basic dynamic load rating C: 22.8 kN

Basic static load rating C0: 8.1 kN

Grease lubrication speed: 6,300 r/min

Oil lubrication speed: 8,000 r/min

Calculation factor e: 0.21

Calculation factor Y0: 3.2

Calculation factor Y2: 4.7

Calculation factor Y3: 3.1

Mass: approx. 0.525 kg

These values are listed for the NSK 1210 K 50x90x20 bearing.

What Does 1210 Mean?

1210 identifies the dimensional series and bearing size.

The principal dimensions are:

d: 50 mm
D: 90 mm
B: 20 mm

The 12 series belongs to the family of double-row self-aligning ball bearings.

What Does K Mean?

The suffix K identifies a tapered bore.

For this bearing:

Bore taper: 1:12

The tapered bore enables the bearing to be mounted using a suitable adapter sleeve or directly onto an appropriately designed tapered shaft. NSK 1210 K specifications confirm the 1:12 tapered bore.

What Does C3 Mean?

C3 indicates radial internal clearance greater than Normal.

This is particularly important for tapered-bore bearings because driving the bearing onto a tapered seat or adapter sleeve expands the inner ring and reduces the bearing's internal clearance.

Therefore, the C3 specification should be retained when replacing a bearing originally marked 1210 K TNG C3.

Self-Aligning Design

The 1210 bearing has two rows of balls and a common spherical outer-ring raceway.

This geometry enables the inner ring and ball assembly to align relative to the outer ring, allowing the bearing to accommodate limited:

• shaft-to-housing misalignment,
• mounting alignment errors,
• shaft deflection.

Self-aligning ball bearings are specifically used where maintaining perfect shaft and housing alignment is difficult.

Open Bearing Design

The NSK 1210 K is an open bearing, without integral seals or shields.

The lubrication and protection of the bearing must therefore be provided by the surrounding bearing arrangement where required.

Radial and Axial Loads

Self-aligning ball bearings are primarily intended for radial loading, but they can also accommodate moderate axial loads in both directions.

Their key functional advantage is their ability to operate despite limited angular misalignment while maintaining relatively low friction.

Tapered Bore and Adapter Sleeve Mounting

The 1:12 tapered bore allows the bearing to be mounted on an adapter sleeve.

During installation, the bearing is driven progressively onto the taper. This causes radial expansion of the inner ring and a corresponding reduction in internal clearance.

For this reason, correct installation of a C3 tapered-bore bearing requires control of the bearing's position and resulting internal clearance.

Typical Applications

NSK 1210 K TNG C3 can be used in appropriately designed:

• industrial machinery,
• conveyor systems,
• agricultural machinery,
• fans,
• transmission systems,
• textile machinery,
• processing equipment,
• shafts susceptible to limited deflection,
• bearing housings requiring self-alignment.

The final selection should consider load, speed, temperature, lubrication, shaft fit, housing arrangement and required operating clearance.

How to Select a Replacement for NSK 1210 K TNG C3

For correct replacement identification, verify:

Series: 1210

Dimensions: 50x90x20 mm

Bearing type: Double-row self-aligning ball bearing

Bore: Tapered

Taper: 1:12

Internal clearance: C3

Cage execution: TNG

Design: Open

A standard 1210 with cylindrical bore or 1210 K with Normal clearance should not automatically be treated as identical to 1210 K TNG C3.

FAQ - Technical Questions

What are the dimensions of NSK 1210 K TNG C3?
The principal dimensions are 50x90x20 mm.

What type of bearing is 1210 K?
It is a double-row self-aligning ball bearing.

What does K mean?
K indicates a tapered bore with a 1:12 taper.

What does C3 mean?
C3 means that the bearing has radial internal clearance greater than Normal.

Is NSK 1210 K sealed?
No. The standard 1210 K is an open bearing.

What is the dynamic load rating?
The basic dynamic load rating is 22.8 kN.

What is the static load rating?
The basic static load rating is 8.1 kN.