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  • 18.9x30x5mm Nitrile Rubber Rotary Shaft Oil Seal R21 / SC
  • 18.9x30x5mm Nitrile Rubber Rotary Shaft Oil Seal R21 / SC
18.9x30x5mm Nitrile Rubber Rotary Shaft Oil Seal R21 / SC
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Oil Seals: Designed to aid trouble-free operation of your equipment, providing an excellent barrier against the escape of oils and greases and preventing the ingress of foreign matter.
Benefits: Excellent wear resistance, good running properties, high resistance to chemicals and petroleum based fuels including petrol, diesel and LPG.

Brand / Quality: Simply NBR Seals - High Quality
Inside Diameter: 18.9mm
Outside Diameter: 30mm
Width: 5mm
Shaft Size not Inside Diameter (d)
Outside Diameter (D)
Width (b)
Oil Seals
An oil seal normally consists of three basic components: The Sealing Element (the nitrile rubber part), the Metal Case, and the Spring. It is a widely used sealing component. The function of a seal is to prevent the leakage of medium along the moving parts. This is mainly achieved by the sealing element. Nitrile Rubber (NBR)
NBR is the most commonly used seal material. It has good heat resistance properties, good resistance to oils, salt solutions, hydraulic oils, and gasoline. Operation temperatures are recommended from -40deg C to 120deg C. It also functions well under dry environment, but only for intermittent periods.
R21 / SC design cross section

Cross section of an R21 / SC style oil seal.

This is a single sealing lip seal arrangement.

The seal cases are made from SAE 1008-1010 Carbon Steel and are often coated in a very thin layer of Nitrile rubber to assist sealing in the housing.
The principle function of the metal case is to impart rigidity and strength to the seal.
The spring is made from SAE 1050-1095 Carbon Spring Steel which has a protective zinc coating.
The principle function of the spring is to maintain an even gripping pressure around the shaft

Viton Chemical Resistance

  • Oscar Agustin, United Kingdom 19/12/2019

    5 of 5 Stars!
    Great quality, good value for money and super service. I will buy all my oil seals from you in future.

  • Marquise Cohen, United Kingdom 30/09/2019

    5 of 5 Stars!
    Called in at your trade counter for replacement oil seals and was served quickly and professionally for top quality oil seals.

  • Ray Amare, United Kingdom 08/03/2018

    5 of 5 Stars!
    cheap but great quality! winner

  • Kian Adriel, United Kingdom 21/10/2015

    5 of 5 Stars!
    thanks nicola for your help

  • Barrett White, United Kingdom 09/06/2015

    5 of 5 Stars!
    It is always nervy when spending such a large amount of money on a website you have never heard of before, so for a trial run I bought this seal: 18.9x30x5mm didn't cost much so I thought why not as I needed it anyway. I'm not very techy so I rang your customer service department who were so helpful, they placed my small order, took my payment and the next day It was in pigeon hole at my workshop (on free delivery). I have now placed my full order consisting of a few bearings, seals, 1 belt and a bag of circlips. I cant recommend your company enough. What a delightful company to buy from

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18.9x30x5mm Nitrile Rubber Rotary Shaft Oil Seal R21 / SC

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Simply bearings are the UK's largest online retailer of bearings, seals, belts, chains, sprockets, lubricants and other associated power transmission equipment.
Simply Bearings Ltd, Halton House, Greenfold Way, Leigh
Greater Manchester
United kingdom

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