SR188ZZ EZO 6.35x12.7x4.763 mm - Stainless Steel Miniature Deep Groove Ball Bearing

SR188ZZ EZO 6.35x12.7x4.763 mm - Stainless Steel Miniature Deep Groove Ball Bearing

EZO SR188ZZ is a miniature inch-series stainless steel deep groove ball bearing with dimensions 6.35x12.7x4.763 mm, corresponding nominally to 1/4x1/2x3/16 inch. The SR designation identifies the stainless steel version of EZO's miniature inch-series bearing, while ZZ indicates metal shields on both sides.

Technical data

EZO SR188ZZ dimensions

The basic dimensions are:

d: 6.35 mm
D: 12.7 mm
B: 4.763 mm

Complete metric dimensions:

6.35x12.7x4.763 mm

Nominal inch dimensions:

1/4x1/2x3/16 inch

The inch dimensions are particularly important when selecting a replacement. The 6.35 mm bore corresponds exactly to 1/4 inch and should not be treated as a standard 6 mm metric bore.

What does SR188ZZ mean?

S - stainless steel version.

R188 - miniature inch-series bearing size corresponding nominally to 1/4x1/2x3/16 inch.

ZZ - metal shields on both sides.

The complete designation SR188ZZ distinguishes the stainless steel EZO version from standard R-series variants.

EZO SR188ZZ construction

SR188ZZ is a single-row deep groove ball bearing consisting of:

• inner ring,
• outer ring,
• balls,
• cage,
• metal shields on both sides.

The bearing is primarily designed to accommodate radial loads. Its deep groove geometry also allows it to accommodate axial loads within the operating limits of the specific bearing arrangement.

Stainless steel SR version

The SR series identifies miniature inch-series EZO bearings in stainless steel execution.

Stainless steel provides increased corrosion resistance compared with a conventional bearing-steel version. However, stainless steel does not provide universal resistance to every chemical or corrosive environment. Compatibility should always be evaluated according to the actual operating conditions.

What does ZZ mean?

The ZZ designation identifies metal shields on both sides of the bearing.

The shields help to:

• reduce the ingress of contaminants,
• protect the raceways and rolling elements,
• retain lubricant inside the bearing,
• maintain low running friction.

ZZ metal shields should be distinguished from elastomer sealing systems used in sealed bearing variants.

SR188ZZ vs R188ZZ

Both bearings have the same basic size:

6.35x12.7x4.763 mm

or nominally:

1/4x1/2x3/16 inch

The principal difference is the material version.

SR188ZZ - stainless steel version.

R188ZZ - standard material version.

Material construction should therefore be considered when selecting a replacement.

SR188ZZ vs open SR188

SR188ZZ has metal shields on both sides.

The open SR188 version does not have ZZ shields.

Although the basic dimensions may be identical, these are different bearing configurations and should not automatically be treated as equivalent.

Why are the inch dimensions important?

SR188ZZ belongs to an inch-dimension bearing series. Its dimensions originate from:

1/4x1/2x3/16 inch

Therefore:

• 6.35 mm must not be rounded to 6 mm,
• 12.7 mm must not be rounded to 13 mm,
• 4.763 mm corresponds nominally to 3/16 inch.

Rounding these dimensions when selecting a replacement can result in choosing an incorrect bearing.

Selection and interchangeability

Before selecting EZO SR188ZZ, verify:

• complete SR188ZZ designation,
• 6.35 mm bore,
• 12.7 mm outside diameter,
• 4.763 mm width,
• inch dimensional system,
• stainless steel construction,
• ZZ metal shields,
• required operating conditions,
• shaft and housing fits.

Similar metric dimensions alone are not sufficient to confirm interchangeability.

Installation

Before installation, ensure that the bearing, shaft and housing surfaces are clean.

When fitting the bearing onto a shaft, mounting force should be applied to the inner ring. When pressing the bearing into a housing, force should be applied to the outer ring.

Mounting force should not be transmitted through the balls, and direct pressure on the ZZ shields should be avoided.

Alternative designations and reference formats

• EZO SR188ZZ
• SR188ZZ EZO
• SR 188 ZZ EZO
• EZO SR 188 ZZ
• SR188 ZZ
• SR188ZZ 6.35x12.7x4.763
• SR188ZZ 1/4x1/2x3/16
• stainless R188 bearing
• stainless R188ZZ bearing

FAQ - EZO SR188ZZ

What are the dimensions of EZO SR188ZZ?

The bearing measures 6.35x12.7x4.763 mm, corresponding nominally to 1/4x1/2x3/16 inch.

What type of bearing is SR188ZZ?

It is a miniature single-row stainless steel deep groove ball bearing.

Is SR188ZZ an inch-series bearing?

Yes. SR188ZZ belongs to a miniature inch-dimension bearing series.

What does SR mean?

SR identifies the stainless steel version of EZO's miniature inch-series bearing.

What does ZZ mean?

ZZ indicates metal shields on both sides of the bearing.

Are SR188ZZ and R188ZZ the same bearing?

They have the same basic dimensions, but SR188ZZ is the stainless steel version. Material construction should be considered when selecting a replacement.

Can the 6.35 mm bore be treated as 6 mm?

No. 6.35 mm is exactly 1/4 inch, which is significantly different from a 6 mm metric bore when selecting a bearing.

Can the 12.7 mm outside diameter be treated as 13 mm?

No. 12.7 mm corresponds exactly to 1/2 inch. A metric bearing with a similar outside diameter is not automatically interchangeable.

SR188ZZ EZO - key information

EZO SR188ZZ is a miniature inch-series stainless steel deep groove ball bearing with dimensions 6.35x12.7x4.763 mm, corresponding nominally to 1/4x1/2x3/16 inch. The ZZ version features metal shields on both sides. Exact inch dimensions and the stainless steel SR construction should be considered when selecting a replacement.

Available from simmering.pl, a specialist supplier of bearings and industrial components. Stock in Poland with worldwide shipping.