SKF 6307-2Z/C3 35x80x21 mm - Deep Groove Ball Bearing

SKF 6307-2Z/C3 35x80x21 mm - Single Row Deep Groove Ball Bearing

SKF 6307-2Z/C3, also commercially designated as 6307 ZZ C3, is a single row deep groove ball bearing with dimensions of 35x80x21 mm, belonging to the SKF 6300 series. The bearing features two non-contact metal shields, identified by the 2Z suffix, and increased C3 radial internal clearance. Its construction accommodates radial loads and axial loads in both directions. The bearing is supplied with factory-applied grease.

Technical Specifications - SKF 6307-2Z/C3

The designation 6307 ZZ C3 is commonly used in bearing trade and distribution. SKF uses the suffix 2Z to identify metal shields on both sides.

Load ratings, speed limits, mass and other operating parameters must correspond to the exact SKF 6307-2Z/C3 execution rather than another bearing variant within the 6307 family.

What Does SKF 6307-2Z/C3 Mean?

6307 - Bearing Series and Dimensions

The designation 6307 identifies a single row deep groove ball bearing belonging to dimensional series 63.

The number 63 identifies the dimensional series, while the bore code 07 corresponds to a nominal bore diameter of 35 mm.

The basic bearing dimensions are 35x80x21 mm.

The bearing consists of an inner ring, an outer ring, one row of balls and a cage that maintains the correct spacing between the rolling elements.

ZZ / 2Z - Metal Shields on Both Sides

The designation ZZ indicates two metal shields, one on each side of the bearing.

In SKF nomenclature, the corresponding suffix is 2Z.

Z-type shields have a non-contact design. Unlike elastomeric contact seals, they do not operate with a sealing lip continuously rubbing against the mating ring surface.

Their main functions include:

• Reducing the entry of larger contaminants into the bearing.

• Helping retain grease inside the bearing.

• Protecting rolling elements and raceways from direct exposure to the surrounding environment.

• Avoiding the additional friction associated with contact sealing lips.

Metal shields do not provide the same sealing performance as appropriately selected contact seals.

A 2Z bearing should not be considered waterproof.

C3 - Increased Radial Internal Clearance

The C3 suffix indicates radial internal clearance greater than normal.

Internal clearance is specified before installation and may change because of bearing fits and thermal conditions.

Common radial internal clearance groups include:

• C2 - Clearance smaller than normal.

• CN - Normal radial internal clearance.

• C3 - Clearance greater than normal.

• C4 - Clearance greater than C3.

• C5 - Clearance greater than C4.

C3 clearance may be required when an interference fit on the shaft or temperature differences during operation reduce the bearing's internal clearance.

C3 does not indicate an increased load rating or a higher accuracy class.

Why Does SKF Use the Designation 6307-2Z/C3?

SKF uses a manufacturer-specific bearing designation system.

In this designation:

• 6307 identifies the basic deep groove ball bearing.

• 2Z indicates metal shields on both sides.

• C3 specifies increased radial internal clearance.

For accurate product identification, both the commercial designation 6307 ZZ C3 SKF and the manufacturer designation SKF 6307-2Z/C3 can be used.

Catalogue Parameters - SKF 6307-2Z/C3

The load ratings and speed values refer to the catalogue SKF 6307-2Z/C3 execution. The stated mass is approximate and may vary according to catalogue presentation and rounding.

The reference speed of 19,000 rpm must not be interpreted as an unrestricted continuous operating speed.

For this execution, the limiting speed of 9,500 rpm and the actual loading, lubrication and temperature conditions must be considered.

Construction and Operating Principle of SKF 6307-2Z/C3

Inner and Outer Rings

The bearing has an inner ring with a nominal bore diameter of 35 mm and an outer ring with a nominal outside diameter of 80 mm.

Both rings contain deep raceway grooves in which the balls operate.

The raceway geometry enables the bearing to accommodate radial loads and axial loads acting in either direction.

The overall bearing width is 21 mm.

Balls and Pressed Steel Cage

The rolling elements are arranged in a single row.

A pressed steel cage maintains the correct spacing between the balls and guides them during bearing rotation.

The cage prevents direct contact between adjacent rolling elements and supports their controlled movement.

Non-Contact Metal Shields

Metal shields are fitted on both sides of the bearing.

They are secured to the outer ring and operate close to the appropriately shaped surface of the inner ring, forming a protective clearance.

Because the shields do not continuously contact the inner ring, they avoid the additional friction generated by contact sealing lips.

However, they do not provide complete protection against water, very fine dust or aggressive environmental conditions.

Factory Grease Lubrication

SKF 6307-2Z/C3 is supplied with factory-applied grease.

The metal shields help retain the lubricant inside the bearing.

The shields should not be removed for routine relubrication unless the equipment manufacturer specifies an appropriate procedure.

Alternative Designations and Reference Numbers

Common written variations include:

• SKF 6307-2Z/C3

• 6307-2Z/C3 SKF

• 6307 ZZ C3 SKF

• SKF 6307 ZZ C3

• 6307 ZZ/C3 SKF

• SKF6307-2Z/C3

The designation ZZ is widely used in the bearing industry to describe metal shields on both sides.

SKF uses 2Z as the corresponding manufacturer suffix.

These alternative written forms are not separate OEM part numbers.

SKF 6307-2Z/C3 vs Other SKF 6307 Variants

These variants share the same basic dimensions of 35x80x21 mm but differ in internal clearance, protective arrangements or operating characteristics.

They are not automatically interchangeable.

SKF 6307-2Z/C3 vs SKF 6307-2RSH/C3

Both variants have the same basic dimensions and C3 radial internal clearance.

However, their protective arrangements differ.

SKF 6307-2Z/C3 uses non-contact metal shields, while SKF 6307-2RSH/C3 incorporates contact seals.

Contact seals may provide improved protection against contamination but generate additional friction and can affect permissible operating speed.

SKF 6307-2Z/C3 vs SKF 6307-2Z

The principal difference is radial internal clearance.

SKF 6307-2Z/C3 has clearance greater than normal, while SKF 6307-2Z without the C3 suffix has normal internal clearance, CN.

These variants should not be substituted without verifying the required operating clearance.

Bearing Selection and Interchangeability

Before ordering SKF 6307-2Z/C3, verify the following requirements:

• Complete manufacturer designation SKF 6307-2Z/C3.

• Shaft diameter of 35 mm.

• Housing bore diameter of 80 mm.

• Available installation width of 21 mm.

• Required C3 radial internal clearance.

• Metal shields on both sides, 2Z.

• Type and magnitude of radial and axial loads.

• Inner and outer ring fits.

• Operating temperature.

• Rotational speed.

• Lubrication conditions.

• Exposure to dust, moisture and other contaminants.

• Equipment manufacturer's design requirements.

A bearing with identical dimensions may have different internal clearance, seals, cage construction or permissible operating characteristics.

Identical dimensions of 35x80x21 mm do not establish full interchangeability.

Applications of SKF 6307-2Z/C3

Based on its single row deep groove ball bearing construction, this variant may be considered for rotating assemblies requiring metal shields on both sides and increased C3 radial internal clearance.

Typical applications for this bearing type include:

• Rotating shaft support assemblies.

• Drive systems and rotating mechanisms.

• Mechanical power transmission assemblies.

• Industrial machinery and equipment.

• Mechanical assemblies subject to radial and bidirectional axial loads.

These are general applications associated with the bearing type and construction.

They are not confirmed OEM applications for the specific SKF 6307-2Z/C3 designation.

Final bearing selection must consider load, speed, temperature, fits and environmental conditions.

Installation and Operating Recommendations

Cleanliness During Installation

Clean the shaft, housing and mating surfaces before installation.

Avoid damaging the metal shields or allowing contaminants to enter the bearing.

Correct Bearing Fits

Bearing fits should correspond to the loading conditions and operating requirements.

Interference fits may reduce radial internal clearance and should be considered when determining the final operating clearance.

Applying Mounting Force

When installing the bearing onto a shaft, apply the mounting force to the inner ring.

When pressing the bearing into a housing, apply the force to the outer ring.

Mounting forces must not be transmitted through the balls and raceways.

Lubrication and Shields

The bearing is supplied with factory-applied grease.

The metal shields should not be removed without a valid technical reason.

Applications exposed to water or significant contamination may require additional protection of the bearing assembly.

Storage

Store the bearing in its original packaging in a clean, dry environment, protected from moisture, contamination and mechanical damage.

Frequently Asked Questions - SKF 6307-2Z/C3

What are the dimensions of SKF 6307 ZZ C3?

The bearing has a bore diameter of 35 mm, outside diameter of 80 mm and width of 21 mm. Its dimensions are 35x80x21 mm.

Are SKF 6307 ZZ C3 and SKF 6307-2Z/C3 the same bearing?

In standard commercial terminology, ZZ indicates metal shields on both sides. SKF uses the suffix 2Z, making 6307-2Z/C3 the appropriate manufacturer designation for this configuration.

What does ZZ mean?

ZZ indicates two metal shields, one on each side of the bearing. The corresponding SKF designation is 2Z.

What does C3 mean?

C3 specifies radial internal clearance greater than normal. It is selected according to bearing fits, thermal conditions and the required operating clearance.

Is SKF 6307-2Z/C3 factory lubricated?

Yes. The bearing is supplied with factory-applied grease, and the metal shields help retain the lubricant inside the bearing.

Is SKF 6307-2Z/C3 waterproof?

No. The 2Z shields have a non-contact design and do not provide complete protection against water. Additional sealing may be required in wet environments.

Can SKF 6307-2RSH/C3 replace SKF 6307-2Z/C3?

Not automatically. The variants differ in sealing design, friction and operating characteristics. Interchangeability must be evaluated for the specific equipment.

Can C3 clearance be replaced with normal clearance?

Not without evaluating the operating conditions. Changing the clearance group may affect operating clearance, temperature, vibration and bearing service life.

SKF 6307-2Z/C3 - Key Technical Information

SKF 6307-2Z/C3, commercially designated 6307 ZZ C3, is a single row deep groove ball bearing measuring 35x80x21 mm. It features two non-contact metal shields, a pressed steel cage and increased C3 radial internal clearance. The bearing is factory grease lubricated and designed to accommodate radial and bidirectional axial loads.

SKF 6307-2Z/C3 at simmering.pl

SKF 6307-2Z/C3 is available through simmering.pl, a specialist supplier of rolling bearings and industrial mechanical components.

We support maintenance departments, machinery repair specialists, engineers and industrial B2B procurement customers.

Our warehouse and order processing operations are located in Lublin, Poland. We supply customers throughout Europe and international markets, with worldwide shipping options.