Stainless Steel Miniature Deep Groove Ball Bearing

SMR63ZZ Stainless Steel Miniature Ball Bearing | 3×6×2.5 mm | In Stock

3 mm Bore × 6 mm OD × 2.5 mm Width · Stainless Steel · Double Metal Shielded · In Stock · Compatibility Verification Available

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Send us your part number, dimensions, photo, or sample — we'll help confirm the correct replacement before you order.

When You Need This Bearing, You're Usually Confirming a Very Small but Very Specific Fit

The SMR63ZZ is a stainless steel miniature deep groove ball bearing measuring 3 × 6 × 2.5 mm.

At this size, even a small difference in bore, outside diameter, width, shielding, or material can affect whether a replacement is suitable.

If you're replacing an existing SMR63ZZ, MR63ZZ, DDL-630ZZ, or another 3×6×2.5 mm miniature bearing, we recommend checking the complete specification before ordering.

Technical Specifications

The 3 × 6 × 2.5 mm boundary dimensions correspond to the widely used MR63 miniature bearing size. NSK's official MR63ZZ product data lists 3 mm bore, 6 mm outside diameter and 2.5 mm width. (NSK MR63ZZ data)

What This Bearing Is

The SMR63ZZ is a stainless steel miniature deep groove ball bearing designed for compact rotating assemblies where limited installation space and corrosion resistance are important.

Its dimensions are:
3 mm bore × 6 mm outside diameter × 2.5 mm width

The ZZ designation indicates double metal shields. The shields help retain internal lubricant and reduce the entry of light external contaminants.

The stainless steel construction makes this type of miniature bearing a practical option for applications where exposure to humidity, moisture, or other corrosion risks makes conventional chrome steel less suitable.

Why Choose a Stainless Steel Miniature Bearing?

• Stainless Steel Construction
  Stainless steel provides greater corrosion resistance than conventional chrome bearing steel in many humid or moisture-exposed applications.

• Compact 3×6×2.5 mm Size
  The small envelope is suitable for miniature mechanisms where installation space is limited.

• Double Metal Shields
  The ZZ configuration helps retain internal lubricant and provides protection against light external contamination.

• Low-Maintenance Applications
  The factory-lubricated, shielded configuration can reduce the need for routine relubrication in suitable applications.

• Suitable for Corrosion-Sensitive Equipment
  Stainless steel can be advantageous in equipment exposed to humidity, water splash, or outdoor conditions, depending on the actual environment.

For other stainless steel bearing options, see our Stainless Steel Bearings category.

Chrome Steel vs. Stainless Steel

If you're choosing between a conventional MR63ZZ-type chrome steel bearing and a stainless steel SMR63ZZ configuration, the main difference is the material.

The choice should be based on the application, not simply on the material.

Load, speed, temperature, lubrication, and environmental conditions should all be considered before changing bearing material.

For the standard chrome steel version, see our MR63ZZ Miniature Ball Bearing.

Where This Bearing Is Used

The SMR63ZZ can be considered for applications such as:

• Fishing reels and compact sporting equipment

• RC models and miniature hobby equipment

• Micro motors and compact drive systems

• Small sensors and rotary mechanisms

• Optical and electronic equipment

• Miniature automation components

• Outdoor or humid applications where corrosion resistance is important

Actual suitability depends on load, speed, temperature, shaft and housing fit, lubrication, and environmental conditions.

See our Miniature Ball Bearings category for other miniature bearing sizes and configurations.

Need to Match an Existing SMR63ZZ Bearing?

For miniature bearings, a difference of only a fraction of a millimeter can be important.

A 3 mm bore alone does not confirm compatibility.

Before ordering, check:
Bore → Outer Diameter → Width → Shield / Seal → Material → Precision → Application

Also confirm whether the original bearing is:
Stainless steel or chrome steel
ZZ shielded or 2RS sealed
Standard or special clearance
Standard or special precision

Not sure which bearing you need? See our Bearing Identification Service.

Send us any of the following:

• Existing bearing number

• Bore, OD, and width

• Bearing photo

• Drawing

• Physical sample

• Equipment model

We'll check the dimensions and configuration before shipment.

Don't have all the information? Send us whatever you have.
A photo, partial dimensions, or the original bearing number may be enough for us to start the identification.

SMR63ZZ Cross-Reference

The 3 × 6 × 2.5 mm miniature bearing size is available under different manufacturer and supplier designations.

Commonly referenced designations include:

These references are provided for identification purposes only.
Do not assume that different manufacturer designations have identical material, clearance, lubrication, precision, or shielding specifications. Confirm the complete configuration before replacement.

Material and Configuration Options

The SMR63ZZ can be supplied in configurations matched to the application, subject to actual availability.

Stainless Steel
Suitable for applications where increased corrosion resistance is important.

Chrome Steel
For general miniature bearing applications where corrosion resistance is less critical, a chrome steel MR63ZZ-type bearing may be more appropriate.

Shield and Lubrication Options
Different shield, clearance, and lubrication requirements may be available depending on the application and quantity.

Tell us your:
Speed · Load · Temperature · Environment · Lubrication Requirement
and we'll confirm the available configuration.

Why Buy From EKB?

Finding a miniature bearing is not always difficult.
Finding the correct miniature bearing specification can be.

EKB helps customers check:
Dimensions → Material → Configuration → Application → Availability

We support difficult-to-source miniature bearing requirements, including stainless steel, special-dimension, replacement, and cross-reference applications.

About EKB

EKB Bearing (Hebei Shuanghejincheng Bearing Co., Ltd.) operates an 18,000 m² factory with 13 automated production lines and 42 high-precision testing units, with products exported to 66 countries.

We support customers with miniature, inch-size, special-dimension, and replacement bearing requirements.

Frequently Asked Questions

What are the dimensions of SMR63ZZ?
The SMR63ZZ size is: 3 mm bore × 6 mm outside diameter × 2.5 mm width.

What does ZZ mean on SMR63ZZ?
ZZ indicates double metal shields.
The shields help retain internal lubricant and reduce the entry of light external contaminants.

What is the difference between SMR63ZZ and MR63ZZ?
Both are associated with the 3 × 6 × 2.5 mm miniature bearing size, but SMR63ZZ refers to a stainless steel configuration while MR63ZZ is commonly used for a chrome steel bearing designation.
The complete material, clearance, lubrication, and precision specification should be confirmed before replacement.

Can SMR63ZZ replace NMB DDL-630ZZ?
It may be possible when the complete dimensions and configuration match.
The NMB designation is a manufacturer-specific reference, so confirm material, shielding, clearance, lubrication, and other application requirements before replacement.

Is SMR63ZZ suitable for wet environments?
Stainless steel construction can provide an advantage in humid or moisture-exposed applications.
However, stainless steel does not make the bearing completely waterproof or suitable for every chemical environment. Actual suitability depends on the operating conditions.

What if I only have the old bearing?
Send us a photo, the dimensions you can measure, the original marking, or the physical sample.
You don't need to know the exact replacement model before contacting us.

Related Miniature Bearings

Looking for other compact bearing sizes? Check out:

• SMR52ZZ Stainless Steel Miniature Ball Bearing

• MR63ZZ Miniature Ball Bearing

Need to Confirm SMR63ZZ?

Send us: Part Number · Dimensions · Photo · Drawing · Sample
We'll confirm: Size · Material · Configuration · Availability
Before you place the order.

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