Frequently Asked Questions

Find the help you need here.

O Ring Materials

Oil Seals

Copper Washers

Bonded Washers

Woodruff Keys

Shipping

Orders

FKM O Rings

Is FKM the same as Viton®?
Yes. Viton® is the brand name from DuPont (now Chemours), while FKM is the general ISO term for this high-grade fluoroelastomer.

What temperature range can FKM handle?
Standard FKM compounds operate from –20 °C up to +200 °C, with high-performance grades handling short-term peaks above 230 °C.

What fluids are FKM O-rings compatible with?
FKM resists oils, fuels, hydraulic fluids, acids, solvents, ozone, and UV exposure. It’s not ideal for low-temp glycol or amines.

Can I use FKM O-rings with petrol or diesel?
Absolutely. They're one of the best materials for fuel system sealing.

Nitrile O Rings

What is an NBR O ring used for?
They’re used to seal oils, fuels, water, and air — especially in automotive, hydraulic, and agricultural equipment.

What’s the temperature range for NBR O rings?
Standard nitrile seals operate from –40 °C to +120 °C.

Are nitrile O rings fuel-resistant?
Yes — NBR is suitable for use with petrol, diesel, engine oil, and hydraulic fluids.

Can I use NBR O rings for drinking water or food?
No — nitrile isn’t certified for potable water or food contact. Use EPDM or silicone for that.

Do you stock imperial sizes too?
Yes, we sell both metric and BS imperial sizes. 

EPDM O Rings

What are EPDM O-rings used for?
EPDM is great for sealing water, steam, and non-oil automotive fluids like brake fluid and coolants.

Are EPDM O-rings safe for drinking water?
Yes – EPDM is commonly used in potable water systems. Many compounds are WRAS or NSF compliant (check specific certifications if needed).

Are EPDM O-rings fuel or oil resistant?
No – EPDM is not suitable for petrol, diesel, or mineral oil. Use Nitrile or FKM for oil/fuel systems.

What’s the temperature range of EPDM O-rings?
Typically from –45 °C to +150 °C.

Do you offer high-temp or peroxide-cured EPDM?
Standard EPDM is stocked, but higher-temp variants are available on request — drop us a line!

Red Silicone O Rings

What’s the temperature range for silicone o rings?
They can handle extreme conditions: –50 °C to +200 °C as standard.

Can I use silicone o rings with oil or fuel?
No — silicone is not suitable for petrol, diesel or mineral oil. Use Nitrile or FKM instead.

Why are silicone o rings good for steam?
Silicone resists heat, steam, and ozone better than most other rubbers, making it ideal for hot water and steam lines.

Are these o rings soft or rigid?
Silicone is softer and more flexible than NBR or FKM – great for delicate fittings and uneven surfaces.

What does R23 or TC mean?

Both refer to the same oil seal profile: double lip, outer rubber coating, internal metal case, and a garter spring. "R23" is the DIN standard name; "TC" is the corresponding Japanese (JIS) code.

Can I use NBR oil seals with diesel or petrol?

Yes — NBR resists mineral oils, fuels, and greases, making it suitable for petrol/diesel applications under normal temperature ranges.

What’s the temperature range for nitrile oil seals?

Typically –40 °C to +120 °C. For anything above that, use FKM/Viton®.

Do these oil seals come pre-lubricated?

No — we recommend lightly greasing the sealing lip during installation to reduce wear on startup.

How do I measure an oil seal?

Use ID (shaft size), OD (bore size), and width. All our listings include these exact dimensions in mm. Often the size can be found printed onto the top surface of the oil seal, should it not have worn on that surface.

What are copper washers used for?

They’re commonly used for sealing fluid connections — particularly in fuel, oil, brake, and hydraulic systems.

Are your copper washers annealed?

Yes — unless otherwise stated, our washers are annealed (heat-treated) for softness and crushability, which helps form a perfect seal.

Can I reuse copper washers?

You can in some cases, but for critical applications (like brake lines or injectors), we recommend replacing with a new one.

How do i measure copper washers?

Measure the inner diameter (ID), outer diameter (OD), and thickness. All of our listings include this information in mm

What is a bonded washer?

A bonded washer has a metal outer ring with a rubber insert to form a seal — commonly used in high-pressure oil, fuel, or hydraulic systems.

Are these self-centering?

Yes – our bonded washers are predominantly self-centering, meaning the seal is fixed in place and perfectly aligned.

Are these genuine Dowty® washers?

No – they are Dowty-type washers, but not made by the Dowty® brand. The term is commonly used to describe this washer design.

What material is the seal made from?

Nitrile (NBR) rubber – a tough, oil-resistant material ideal for most standard applications.

What sizes are available?

We offer a full range of metric (M6–M30+) and imperial (1/4”–1”) sizes. We also offer 4 different types of kits. 

Do you offer stainless or Viton® types?

Not listed online yet, but we may have them — email us and we’ll help.

What is the advantage of a Woodruff key over a straight key?

Woodruff keys provide better seating in curved keyways, reduce the likelihood of key rollover, and are ideal for applications requiring high precision.

Can I get stainless steel Woodruff keys?

Yes – at the moment we only stock carbon steel woodruff keys, however we will add stainless steel to our range soon.

Are your Woodruff keys made to any standard?

Our keys are manufactured to DIN 6888 or BS 46 specifications depending on the size and style.

Do I need to machine the shaft to use a Woodruff key?

Only if you're installing one for the first time. The shaft needs a milled, semi-circular keyway to accept the Woodruff key. However, if you're replacing an old key, no machining is needed as long as the original keyway is intact.

Where do you ship to?

What are the shipping lead times for where I live?

United Kingdom

  • Standard shipping takes 2-3 days.
  • Express next day delivery is available from Monday to Friday.

United States, Europe, Australia, and Asia

  • Express shipping takes 2-3 days.

South America

  • Express shipping takes 4-5 days.

How much will my shipping costs be?

We have kept it simple:

UK - £6.75 - for DPD next day

UK - £2.49 - for RM 48 hour service

Rest of the World - £16.99 - Airfreight

What shipment options are available?

In the UK we have DPD for next day delivery or Royal Mail 48 for economy. 

Who are your shipping providers?

DPD and Royal Mail

When will my order be dispatched?

We will ship all orders received the same day up to 15:30 (Monday-Thursday) and up to 14:30 on a Friday.

Currently we do not ship on a weekend.

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