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  • 18x35x5mm Nitrile Rubber Rotary Shaft Oil Seal R21 / SC
  • 18x35x5mm Nitrile Rubber Rotary Shaft Oil Seal R21 / SC
18x35x5mm 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: 18mm
Outside Diameter: 35mm
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

  • Shawn Kent, United Kingdom 19/12/2019

    5 of 5 Stars!
    Very pleased with the customer service, couldn't do enough for me when I called in for these oil seals, which were superb quality by the way. I'll definitely be back. Highly recommended.

  • Oliver Pratt, United kingdom 27/09/2019

    5 of 5 Stars!
    Thanks for getting my oil seals to me so fast

  • Corbin Bruno, United Kingdom 08/03/2018

    5 of 5 Stars!
    great service for a small order

  • Albert Skinner, United Kingdom 29/12/2015

    5 of 5 Stars!
    Fantastic seals. Thanks alot

  • Nathen Leigh, United Kingdom 14/12/2015

    5 of 5 Stars!
    Excellent oil seal, the price was def what I was looking to pay!!

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18x35x5mm 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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