SKF 30x42x7 HMSA10 RG NBR Radial Shaft Seal

SKF 30x42x7 HMSA10 RG NBR Radial Shaft Seal

SKF 30x42x7 HMSA10 RG is a radial shaft seal measuring 30x42x7 mm, manufactured in the HMSA10 design from SKF's optimized RG nitrile rubber compound.

The seal combines a spring-loaded primary sealing lip, an auxiliary lip and a rubber-covered outside diameter. It is designed to seal between a rotating shaft and stationary housing.

SKF 30x42x7 HMSA10 RG Dimensions

d1 - Shaft diameter: 30 mm
D - Housing bore diameter: 42 mm
b - Nominal width: 7 mm
Dimensions: 30x42x7 mm
Design: HMSA10
Material: NBR nitrile rubber
SKF material code: RG
Material hardness: 75 Shore A
Auxiliary lip: Yes
Garter spring: Yes
Outside diameter: Rubber covered
Manufacturer: SKF

What Does HMSA10 RG Mean?

The designation HMSA10 RG identifies both the seal design and elastomer material.

HMSA10 - SKF radial shaft seal design with an additional auxiliary lip.

RG - SKF's optimized nitrile rubber NBR compound.

SKF distinguishes the following principal variants within this seal family:

HMS5 RG - without auxiliary lip, nitrile rubber
HMS5 V - without auxiliary lip, fluoro rubber
HMSA10 RG - with auxiliary lip, nitrile rubber
HMSA10 V - with auxiliary lip, fluoro rubber

For correct replacement selection, the complete 30x42x7 HMSA10 RG designation should therefore be verified rather than dimensions alone.

HMSA10 Design with Auxiliary Lip

The primary sealing lip operates against the rotating shaft and is responsible for retaining lubricant on the required side of the seal.

The HMSA10 design incorporates an additional auxiliary lip that provides an extra barrier against contaminants approaching the primary sealing area.

SKF designs the HMSA10 auxiliary lip as a non-contacting lip. This provides additional contamination exclusion without the friction associated with a second contacting sealing lip.

According to SKF, HMSA10 seals can therefore normally operate at the same speeds as corresponding single-lip HMS5 seals.

Spring-Loaded Primary Sealing Lip

The primary sealing lip is supported by a garter spring.

The spring helps maintain the required radial contact between the elastomer lip and the shaft surface.

SKF optimizes the sealing lip and flex section to accommodate:

dynamic shaft runout,
shaft-to-bore misalignment,
progressive sealing lip wear.

The spring-loaded design helps the sealing lip respond quickly to changes in shaft position during operation.

SKF RG Optimized Nitrile Rubber

The suffix RG identifies more than generic NBR material.

SKF developed RG as an optimized nitrile rubber compound for HMS5 and HMSA10 radial shaft seals.

SKF identifies its key characteristics as:

good ageing resistance,
very good compatibility with synthetic oils,
very good pumping ability,
good wear resistance.

SKF specifies a hardness of 75 Shore A for the nitrile rubber compound used in this seal design.

Oil Pumping Ability of SKF RG

One of the important characteristics SKF highlights for its RG compound is very good pumping ability.

In a radial shaft seal, the microscopic structure of the sealing contact can help transport small quantities of oil from the air side back toward the oil side.

SKF defines pumping ability as the time required for a seal to return a specified quantity of oil from the air side to the oil side.

The microstructure of the SKF RG nitrile compound has been optimized to promote this oil-return effect.

This contributes directly to the primary purpose of a radial shaft seal: controlling lubricant leakage along a rotating shaft.

Rubber-Covered Outside Diameter

SKF HMSA10 RG seals have a rubber-covered outside diameter.

The outside surface incorporates specially designed beads that improve the interface between the seal and housing bore.

According to SKF, these beads help:

improve sealing in the housing bore,
improve seal retention,
prevent spring-back during installation.

The rubber outside diameter can also provide effective sealing in housings with considerable surface roughness and in split housings.

HMSA10 RG vs HMS5 RG

Both designs use the optimized SKF RG nitrile rubber compound and a spring-loaded primary sealing lip.

The principal difference is:

HMS5 RG - without auxiliary lip
HMSA10 RG - with auxiliary lip

HMSA10 therefore provides an additional barrier against contaminants reaching the primary sealing area.

HMSA10 RG vs HMSA10 V

Both use the HMSA10 seal design but differ in elastomer material:

HMSA10 RG - nitrile rubber NBR
HMSA10 V - fluoro rubber FKM

SKF uses the V compound particularly where operating temperatures exceed the capabilities of nitrile rubber.

Identical seal dimensions therefore do not automatically mean identical operating characteristics.

What Is SKF 30x42x7 HMSA10 RG Used For?

Radial shaft seals operate between rotating and stationary machine components.

Their principal functions are to:

retain oil or grease on the required side of the seal,
reduce lubricant leakage along the rotating shaft,
help prevent external contaminants from reaching the primary sealing area.

Actual suitability depends on the lubricant or medium, operating temperature, shaft speed, pressure, shaft surface quality and installation conditions.

Shaft Surface Requirements

For HMS5 and HMSA10 radial shaft seals, SKF provides recommendations for the shaft counterface.

Typical SKF recommendations include:

Shaft tolerance: h11
Surface roughness Ra: 0.2 to 0.5 µm
Surface roughness Rz: 1.2 to 3 µm
Shaft surface hardness: minimum 45 HRC

SKF recommends a shaft surface without directional lead, typically produced by plunge grinding.

Correct shaft surface preparation is important because the counterface directly affects sealing performance and service life.

Technical Specification

Manufacturer: SKF
Designation: 30x42x7 HMSA10 RG
Product type: Radial shaft seal
Design: HMSA10
Material: NBR nitrile rubber
SKF material code: RG
Material hardness: 75 Shore A
Shaft diameter: 30 mm
Housing bore diameter: 42 mm
Nominal width: 7 mm
Dimensions: 30x42x7 mm
Primary sealing lip: Spring-loaded
Garter spring: Yes
Auxiliary lip: Yes
Auxiliary lip type: Non-contacting
Outside diameter: Rubber covered

How to Select SKF 30x42x7 HMSA10 RG

The complete product identification is:

SKF -> 30x42x7 mm -> HMSA10 -> RG

When selecting a replacement, verify all three dimensions together with the seal design and material.

Matching 30x42x7 mm dimensions alone does not guarantee full interchangeability.

Another 30x42x7 seal may differ in elastomer material, sealing lip configuration, outside diameter design or permitted operating conditions.

FAQ

What are the dimensions of SKF 30x42x7 HMSA10 RG?

The seal is designed for a 30 mm shaft and 42 mm housing bore, with a nominal width of 7 mm.

What does HMSA10 mean?

HMSA10 identifies an SKF radial shaft seal design with an additional auxiliary lip.

What does RG mean?

RG identifies SKF's optimized nitrile rubber NBR compound developed for HMS5 and HMSA10 radial shaft seals.

What is the hardness of SKF RG?

SKF specifies a material hardness of 75 Shore A for the nitrile rubber compound used in this seal design.

Does SKF 30x42x7 HMSA10 RG have a garter spring?

Yes. The primary sealing lip is supported by a garter spring.

Does HMSA10 have an auxiliary lip?

Yes. The HMSA10 design incorporates an additional non-contacting auxiliary lip to improve contamination exclusion.

Is SKF RG compatible with synthetic oils?

SKF identifies very good compatibility with synthetic oils as one of the key characteristics of its RG nitrile compound.

What is the difference between HMSA10 RG and HMS5 RG?

HMSA10 RG has an additional auxiliary lip, while HMS5 RG does not. Both use SKF's optimized RG nitrile rubber compound.

Is every 30x42x7 shaft seal interchangeable?

No. In addition to the 30x42x7 mm dimensions, the seal design, material, lip configuration and operating requirements should be verified.

AI OVERVIEW

SKF 30x42x7 HMSA10 RG is an NBR radial shaft seal for a 30 mm shaft and 42 mm housing bore, with a nominal width of 7 mm. The HMSA10 design features a spring-loaded primary sealing lip and an additional non-contacting auxiliary lip for contamination exclusion. RG identifies SKF's optimized nitrile rubber compound with a hardness of 75 Shore A, good ageing and wear resistance, very good compatibility with synthetic oils and very good pumping ability. The rubber-covered outside diameter improves sealing and retention in the housing bore.