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Radial Shaft Seals: Sizing, Material Selection, and Application Guide

Quick Answer: A radial shaft seal is a lip seal installed between a rotating shaft and a stationary housing. The seal keeps lubricant in and blocks dust, water, and contamination. For a quotation, send CORASEALS the shaft diameter, housing bore, seal width, material, fluid, operating temperature, shaft speed, and required quantity.

A radial shaft seal is also called a rotary shaft seal, oil seal, or lip seal in many industrial markets. CORASEALS supplies radial shaft seals as part of the oil seal and rotary shaft seal product range. This guide explains sizing, material selection, installation conditions, and the information needed for a radial shaft seal quote.

What Is a Radial Shaft Seal?

A radial shaft seal has a flexible sealing lip that contacts the rotating shaft. The OD fits into the housing bore. A metal or rubber outer shell holds the seal in position. A garter spring usually keeps the lip in contact with the shaft surface. The seal prevents lubricant leakage and keeps dust, water, and abrasive particles out.

Common specification terms include ID, OD, width, shaft diameter, housing bore, lip type, garter spring, dust lip, and seal profile. The seal ID is normally smaller than the shaft diameter. This lip interference creates the sealing contact. The OD must match the housing bore with the correct fit.

Where Radial Shaft Seals Are Used

Radial shaft seals are used on gearboxes, pumps, motors, axles, bearing housings, transmissions, and rotating equipment assemblies. Buyers use these seals in automotive, agriculture, mining, construction machinery, and general industrial equipment. If a shaft rotates and lubricant is present, a radial shaft seal is often the correct sealing element.

How to Measure and Specify a Radial Shaft Seal

Measure the shaft diameter at the sealing contact area. Measure the housing bore where the seal outer diameter sits. Measure the available width in the housing. Specify the size in this order: shaft diameter x housing bore x width, or ID x OD x width. Confirm the unit in millimetres or inches.

Do not order by a TC, SC, BA, or VB code alone. These profile codes change between seal catalogs. Always confirm the outer surface type, lip configuration, spring position, dust lip, and dimensions. Send a drawing or sample photo if the old seal is worn or unmarked.

DIN 3760 and ISO 6194 are common dimensional references for radial shaft seals. Use the supplier drawing to confirm lip design, spring position, and OD construction.

Material Selection for Radial Shaft Seals

Seal material must match the oil, grease, chemical exposure, temperature, and shaft speed. NBR is the most common material for mineral oil and gear oil. FKM works where higher temperature and chemical resistance are needed. HNBR offers good oil resistance and improved wear in many industrial drives. EPDM suits water and some brake fluids but is not suitable for most mineral oil environments. Silicone has a wide temperature range but lower wear resistance. PTFE lip seals can handle chemical attack, dry running, and low friction, but they require careful shaft surface and runout control.