TC FB Skeleton Oil Seal | Metric Rotary Shaft Seal NBR 70 | ID 35–40mm

Measure three dimensions with calipers: the shaft diameter (= ID), the housing bore diameter (= OD), and the housing depth (= Height). For example, if your shaft is 40mm, your bore is 60mm, and your housing is 10mm deep, you need a 40×60×10mm seal. All three must match — a seal that fits the shaft but not the bore will leak immediately. Sizes are listed in the variant selector as ID×OD×Height in mm.

NBR stands for Nitrile Butadiene Rubber; the "70" refers to Shore A hardness. NBR 70 is the most common oil seal compound and generally resists petroleum-based oils, hydraulic fluids, greases, and fuels. It typically handles temperatures from -40°F to +250°F (-40°C to +120°C). If your application involves synthetic esters, ketones, or very high temperatures (above 300°F), a Viton (FKM) seal is typically recommended instead.

NBR 70 seals generally perform well in environments with oil, grease, and incidental water splash — common in agricultural and construction equipment. For prolonged UV exposure, saltwater immersion, or ozone-rich environments, a Viton or EPDM seal is typically more appropriate. Contact us to confirm suitability for your specific outdoor use case.

TC refers to the lip configuration: a double-lip design with a primary sealing lip (retains lubricant) and a secondary dust lip (excludes contaminants). FB (Fully Bonded) means the rubber compound is bonded to the metal skeleton on all surfaces, so the outer diameter is rubber-covered for a secure, leak-free press-fit into the housing — no sealant required in most cases.

NBR 70 TC seals are generally rated for shaft surface speeds up to approximately 4–6 m/s (roughly 800–1,200 ft/min) under normal lubricated conditions. Actual performance depends on shaft surface finish, operating temperature, and lubricant viscosity. For high-speed spindle or pump applications, contact us to confirm compatibility before ordering.

Yes. All dimensions follow metric standards (millimeters), making them directly interchangeable with OEM metric seals used in European and Asian agricultural equipment, automotive axles, electric motors, and hydraulic systems. They are not designed as direct replacements for inch-dimensioned seals — always verify your measurements in mm.

For optimal lip seal life, the shaft surface finish is typically recommended to be Ra 0.2–0.8 μm (8–32 μin), with a hardness of generally 55–65 HRC. A shaft that is too rough will accelerate lip wear; one that is too smooth may not allow the lip to seat properly. Avoid installing seals on pitted, scored, or corroded shafts without first repairing the surface.