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  • 4x16x6mm Nitrile Rubber Rotary Shaft Oil Seal R21 / SC Style
  • 4x16x6mm Nitrile Rubber Rotary Shaft Oil Seal R21 / SC Style
4x16x6mm Nitrile Rubber Rotary Shaft Oil Seal R21 / SC Style
Great rates on shipping on any order regardless of size

4x16x6mm Nitrile Rubber Rotary Shaft Oil Seal R21 / SC Style


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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: 4mm
Outside Diameter: 16mm
Width: 6mm
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

  • Howard Luciano, United Kingdom 02/08/2019

    5 of 5 Stars!
    Really pleased with the quality of these products. Packaged very well and arrived sooner than expected. 10/10!

  • Carter Allison, United Kingdom 10/07/2019

    4 of 5 Stars!
    Great quality product and fantastic service. Many thanks!

  • Brendan Nicholls, United Kingdom 02/08/2018

    5 of 5 Stars!
    arrived quickly and and now we are back up and running!

  • Amare Daniel, United Kingdom 29/11/2017

    5 of 5 Stars!
    Does the job..

  • Candis Myrtle, United Kingdom 09/08/2016

    5 of 5 Stars!
    Quality seal delivered quickly. Always order from Simply Bearings and get the same brilliant service each time I order. Thanks very much

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4x16x6mm Nitrile Rubber Rotary Shaft Oil Seal R21 / SC Style

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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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