What is a BS 1806 O-ring?

BS 1806 is the British Standard sizing system for O-rings, defining inside diameters and cross-sections for standard sizes BS001 through BS932. The sizes originate from imperial measurements and are identical to the AS568 (US) system. It's the most common O-ring sizing system used in UK industry.

Are BS 1806 and AS568 O-ring sizes the same?

Yes. BS 1806 and AS568 O-ring sizes share identical dimensions. A BS110 is the same O-ring as an AS568-110. The only difference is the naming convention. Both use imperial-origin dimensions expressed in inches and millimetres.

How do I measure an O-ring to find its BS size?

Lay the O-ring flat without stretching it. Measure the inside diameter (ID) across the inner opening with calipers. Then measure the cross-section (CS) by compressing the ring slightly and measuring its thickness. Match both values to the BS 1806 chart. Used O-rings may be slightly stretched, so measure a new one if possible.

What does the O-Ring Size Chart - BS 1806 provide?

The O-Ring Size Chart - BS 1806 provides detailed dimensions for O-rings from size BS001 to BS050, listing inside diameter (ID) and cross-section (CS) in both metric and imperial units.

What are the CS sizes for BS004 and higher?

The O-Ring Size Chart - BS 1806 shows that starting at BS004, the cross-section size increases to 1.78 mm (approximately 0.070 inches).

How do you choose between ISO 3601 metric sizes and BS 1806 for O-rings?

The choice depends on compatibility with existing systems; BS 1806 is still widely used in the UK despite the adoption of ISO 3601, due to its historical usage.

What are some common variants of O-ring sizes listed under BS 1806?

Common variants include different cross-section sizes stepping from 1.27 mm to 1.78 mm at BS004 and further increasing to 2.62 mm at BS029.

Where can UK engineers find suppliers for O-rings based on the BS 1806 standard?

Engineers in the UK can look for suppliers who specialize in industrial rubber products, such as Parker O-Ring Division or Beswick Engineering Company Ltd., which stock O-rings conforming to the BS 1806 standard.

What is the cost and availability of O-rings according to BS 1806?

The cost varies based on size and material; typically, larger sizes like BS029 are more expensive due to higher material usage. Availability is generally good through major UK suppliers, though custom or less common sizes may have longer lead times.

What is the significance of AS568 (US) sizing in relation to BS 1806?

The O-Ring Size Chart - BS 1806 dimensions are identical to those of the AS568 (US) sizing system, facilitating interchangeability between UK and US engineered systems.

BS O-ring sizes follow the BS 1806 British Standard system, running from BS001 to BS050 with the inside diameter and cross-section given in both metric and imperial. BS001 has a 1.07 mm ID and 1.27 mm cross-section, while BS050 reaches 107.62 mm ID with a 2.62 mm cross-section. BS 1806 sizes are identical to the AS568 US sizing system, so the same reference covers both.

The BS 1806 O-ring chart lists sizes BS001 to BS050 with inside diameter (ID) and cross-section (CS) in millimetres and inches. Cross-sections step from 1.27 mm at BS001 up to 1.78 mm at BS004, then to 2.62 mm at BS029. To use the BS 1806 chart, measure the groove inside diameter and the O-ring cord diameter with calipers, then match both to the table to find the BS reference.

bs1806 / as568 standard

BS 1806 is the British Standard O-ring sizing system and its dimensions are identical to the AS568 US standard, so a BS 1806 part number maps directly to its AS568 equivalent. Both run from BS001 (1.07 mm ID, 1.27 mm CS) to BS050 (107.62 mm ID, 2.62 mm CS). BS 1806 remains widely used across UK engineering despite the adoption of the ISO 3601 metric sizing system.

BS O-ring sizes are set by BS 1806, covering BS001 through BS050. Smaller references such as BS004 to BS028 share a 1.78 mm cross-section, while BS029 upwards step up to a 2.62 mm cross-section. Inside diameters range from 1.07 mm at BS001 to 107.62 mm at BS050. BS 1806 dimensions match the AS568 US sizing system across the full range.

BS O Ring Sizes Chart BS1806 and AS568

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