The Oil Seal 21x31x7 NBR TC (21x31x7 mm) renews the sealing on a 21 mm shaft where grease or oil must stay in and grit must stay out — a typical fitment in compact motors, power tools, small pumps and precision gear units.
Size and material details
| Inner diameter (shaft) | 21 mm |
| Outer diameter (bore) | 31 mm |
| Width | 7 mm |
| Seal type | TC — double lip, rubber covered, garter spring |
| Material | NBR – Nitrile |
| Temperature range | -30 °C … +100 °C |
How the TC design works
Every TC seal combines three elements: a rubber-covered case that grips the bore, a spring-loaded sealing lip that follows shaft runout, and a dust lip that shields the main lip from contamination.
Material: NBR – Nitrile
Material-wise this is NBR nitrile: a balanced compound for mineral oil, diesel-range fuels and greases at moderate temperatures — ideal for rotating equipment. Two cautions: no exposure to glycol-based brake fluid, and keep stock seals out of sunlight.
Should the shaft read slightly below the listed size — typically a few tenths of a millimetre — no concern: the lip’s interference fit accounts for it.
Ordering & delivery
- Individual pieces, no minimum order — checkout in US dollars.
- Our prices do not cover customs duties or taxes your country may apply; those fall to the buyer.
- One worldwide flat shipping fee · every parcel tracked, number emailed.
- Before you buy, confirm the fit: measuring guide or free dimension check.
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