The Oil Seal 50x78x12 NBR TC is a TC rotary shaft seal sized 50x78x12 mm (ID × OD × width). It keeps oil inside and dirt outside on a 50 mm shaft seated in a 78 mm bore — a size common in steel-plant gearboxes, screw conveyors and big-bore rotating shafts.
Size and material details
| Inner diameter (shaft) | 50 mm |
| Outer diameter (bore) | 78 mm |
| Width | 12 mm |
| Seal type | TC — double lip, rubber covered, garter spring |
| Material | NBR – Nitrile |
| Temperature range | -30 °C … +100 °C |
Inside the TC double-lip design
Its TC construction pairs a rubber-covered OD (a snug press-fit in the bore) with a spring-energised sealing lip and a separate dust lip, so both oil retention and contamination exclusion are covered.
Why NBR for this seal
Nitrile rubber (NBR) is the workhorse of oil sealing: fully compatible with mineral oils, lubricating greases and common hydraulic fluids — the media found in most gearboxes and motors. Avoid contact with brake fluid, and keep spares shaded from sunlight.
It is normal for a shaft to measure a few tenths of a millimetre smaller than nominal; the sealing lip is engineered to take up that difference.
Ordering & delivery
- Every order is per piece with no MOQ; payments in US dollars.
- Prices exclude duties and taxes that your customs may assess — those are the buyer’s obligation.
- Flat worldwide shipping · email delivery of the tracking number.
- Double-check dimensions before ordering: how to measure an oil seal, or message us your size for a free check.


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