TB Oil Seals - Durus

What Is a TB Oil Seal?

The TB type uses a Type B case (steel with a chamfered lead-in edge, no rubber coating) combined with the Standard single lip configuration. The bare metal OD provides a tight interference fit in precision-bored hard housings (cast iron, steel) where the rubber coat of a TC type would be unnecessary. The single lip reduces friction compared to a double-lip TC and is appropriate for clean operating environments.

Construction summary:
Case Type: B (bare metal)
Lip Configuration: Standard single lip

When to Choose TB

• Hard housing materials with precision-bored seal cavities
• Clean operating environments (interior gearbox positions, sealed motor housings)
• Applications where TC seals previously failed due to bore size tolerance (TB tight fit handles oversized bores)
• Cost-sensitive applications where the cheaper bare-metal case is acceptable

When NOT to Choose TB

• Soft housings (aluminum, plastic) - the bare-metal case can score the bore during install
• Marginal or worn housing bores where rubber coat would accommodate tolerance
• Dirty environments with dust exposure (use TC or TB2 instead)

Related Seal Types

Frequently Asked Questions

What does TB stand for in oil seal designations?

TB combines Type B case (the "B") with the standard single lip with garter spring lip configuration (the "T"). The B case is a steel cup with a chamfered lead-in edge but no rubber coating on the outer diameter - providing direct metal-to-housing contact for the press-fit seal. The configuration provides a single primary sealing lip without an auxiliary dust lip.

When should I choose TB instead of TC?

Choose TB only when the housing is hard material (cast iron, steel) with a precision-bored seal cavity, the operating environment is clean (no dust exposure), and the cost savings of bare-metal vs rubber-coat justifies sourcing a different type than the default. For most general industrial applications, TC remains the better choice - the marginal cost premium buys both bore tolerance accommodation and dust exclusion.

Can a TB oil seal be installed in an aluminum housing?

It is not recommended. The bare-metal case of a TB seal can score or damage soft aluminum housing bores during press-fit installation, compromising the OD seal. For aluminum, brass, or plastic housings, choose a TC type with full rubber coat - the elastomer OD seals against soft materials without damage and accommodates the higher tolerance variations typical of softer machined housings.

Does TB provide dust exclusion?

No - TB is a single lip configuration with no auxiliary dust lip. The primary sealing lip retains lubricant, but dust, dirt, and contaminants can directly contact the lip without an outer barrier. For applications with dust exposure, choose TB2 (same case construction with added dust lip) or TC (rubber-coated case with double lip). Reserve TB for verified clean operating environments.