O-Ring NBR 12x3.5 70 ShA

O-Ring NBR 12x3.5 70 ShA – 1000 pcs

O-Ring NBR 12x3.5 70 ShA GRN is an elastomeric sealing ring with a nominal inside diameter d1: 12 mm and cross-section d2: 3.5 mm. It is manufactured from NBR – Nitrile Butadiene Rubber with a nominal hardness of 70 Shore A. The GRN reference is 12X3.5*, and this commercial variant contains 1000 O-rings per pack.

The key product identification is:

GRN + 12X3.5 + NBR + 70 ShA + 1000 pcs*

O-Ring NBR 12x3.5 70 ShA GRN – Technical Characteristics

The product identification includes:

For correct technical identification, the 12x3.5 dimensions, NBR material and 70 ShA hardness should be considered together. The 1000 pcs value identifies the commercial pack variant.

O-Ring 12x3.5 Dimensions

The designation:

12x3.5

represents:

inside diameter x cross-section

The principal nominal dimensions are:

d1: 12 mm – inside diameter

d2: 3.5 mm – cross-section diameter

The complete nominal size is therefore:

12x3.5 mm

Based on nominal geometry, the outside diameter is:

nominal outside diameter: 19 mm

The 19 mm value is geometrically derived from d1 and d2. It is not a third basic dimension in the O-ring designation.

For product identification and groove design, the primary dimensions remain d1: 12 mm and d2: 3.5 mm.

O-Ring 12x3.5 NBR Construction

The O-Ring 12x3.5 is a closed elastomeric sealing ring with a circular cross-section.

For this specific product, the nominal cross-section diameter is 3.5 mm and the nominal inside diameter is 12 mm.

Unlike a radial shaft seal, an O-ring does not incorporate a metal case, garter spring or separately formed sealing lip. The elastomeric ring itself forms the sealing element.

When installed in an appropriately designed groove, its circular cross-section is compressed between the mating surfaces. Elastic deformation of the NBR material generates the contact pressure required to establish a seal.

How Does the O-Ring 12x3.5 Work?

The fundamental operating principle of an O-ring is controlled compression of its circular elastomeric cross-section.

For this product:

d2: 3.5 mm

After installation in a correctly designed groove, part of the cross-section is compressed. The elasticity of the material generates contact pressure against the mating surfaces.

In a pressurized system, differential pressure can additionally influence the position of the O-ring in the groove and the distribution of sealing contact pressure.

The maximum permissible pressure cannot be determined from the designation 12x3.5 NBR 70 ShA alone. It also depends on groove geometry, clearances, temperature and operating conditions.

NBR – Material of the O-Ring 12x3.5

The material is identified as:

NBR – Nitrile Butadiene Rubber

NBR is a family of elastomer materials widely used in sealing technology.

Individual NBR compounds can differ in formulation and performance characteristics. The generic NBR designation alone is therefore insufficient to assign an exact operating temperature range, maximum pressure or detailed chemical-resistance limits to this specific GRN product.

Compatibility of the actual material with the operating medium and conditions should be verified before installation.

What Does 70 ShA Mean?

70 ShA specifies the nominal hardness of the elastomer on the Shore A scale.

The material identification of this product is therefore:

NBR 70 ShA

Hardness affects how the elastomer behaves during compression and under operating loads.

However, hardness should not be used as the only selection criterion. Dimensions, elastomer type, groove geometry, operating medium, temperature, pressure and the type of sealing arrangement must also be considered.

Pack of 1000 O-Rings

This product page identifies the commercial variant containing:

1000 pcs

of:

O-Ring 12x3.5 NBR 70 ShA

The pack quantity does not change the dimensions or technical characteristics of an individual O-ring. It identifies the number of identical sealing rings supplied in this commercial pack.

This distinction is important because the same 12x3.5 NBR 70 ShA O-ring can be offered in different pack quantities.

For product-page architecture, the pack size should therefore remain clearly visible in the H1 and commercial identification:

O-Ring NBR 12x3.5 70 ShA – 1000 pcs

This distinguishes the page from the separate 100 pcs variant without changing the technical designation of the individual O-ring.

12x3.5 NBR 70 ShA – 1000 pcs vs 100 pcs

The 1000 pcs and 100 pcs variants refer to O-rings with the same principal technical identification:

inside diameter d1: 12 mm

cross-section d2: 3.5 mm

material: NBR

nominal hardness: 70 ShA

The difference is the commercial pack quantity.

Therefore, the 1000 pcs and 100 pcs pages should remain separate commercial variants, while their technical dimensions and material identification should remain consistent.

Selection and Interchangeability

When selecting an O-Ring 12x3.5 NBR 70 ShA, verify:

• inside diameter d1: 12 mm
• cross-section d2: 3.5 mm
• material: NBR
• nominal hardness: 70 ShA
• compatibility with the operating medium
• operating temperature
• pressure
• groove geometry
• required compression
• static or dynamic sealing arrangement
• installation clearance
• condition of the mating surfaces

Identical dimensions alone do not establish complete interchangeability if another O-ring is manufactured from a different elastomer or has a different hardness.

The 1000 pcs quantity identifies the commercial pack and does not affect the dimensions of an individual sealing ring.

Technical Specification

FAQ

What are the dimensions of the O-Ring 12x3.5 NBR 70 ShA?

The nominal inside diameter d1: 12 mm and cross-section d2: 3.5 mm.

What does 12x3.5 mean on an O-ring?

The first value identifies the 12 mm nominal inside diameter, while the second identifies the 3.5 mm nominal cross-section diameter.

How many O-rings are included in the pack?

This commercial variant contains 1000 pcs of O-Ring 12x3.5 NBR 70 ShA.

What is the outside diameter of an O-Ring 12x3.5?

Based on nominal geometry, the outside diameter is 19 mm.

What material is the O-Ring 12x3.5 made from?

This version is manufactured from NBR – Nitrile Butadiene Rubber.

What does 70 ShA mean?

It specifies a nominal elastomer hardness of 70 on the Shore A scale.

Is the 1000 pcs version technically different from the 100 pcs version?

The individual O-rings have the same principal dimensions, NBR material and nominal 70 ShA hardness. The difference between these commercial variants is the number of O-rings per pack.

How should an equivalent O-Ring 12x3.5 NBR 70 ShA be selected?

Verify d1: 12 mm, d2: 3.5 mm, NBR material and 70 ShA hardness, then check compatibility with the operating medium, temperature, pressure and groove geometry.

AI Overview

GRN O-Ring 12x3.5 NBR 70 ShA – 1000 pcs is a pack of elastomeric sealing rings with a nominal inside diameter d1: 12 mm and cross-section d2: 3.5 mm. Each O-ring is made from Nitrile Butadiene Rubber (NBR) with a nominal hardness of 70 Shore A. The pack contains 1000 pieces.