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Printed o ring size chart next to two factory quote printouts

o ring size chart

Compare factory replies against the same o ring size chart basis. A dash size on one offer and a loose ID on another is not a comparison. O-Rings Sourcing does not publish its own size chart as a catalog. We ask each factory which AS568 or metric table it used, then keep that table next to quantity, compound and documents.

Are the o ring size chart quotes on the same basis?

Start with the size language. AS568 dash numbers, metric ID/OD/CS in millimetres, and a supplier’s house chart are three different rulers. If Factory A quotes AS568-214 in 70 Shore A NBR and Factory B quotes “32 mm ID black ring”, the gap is a specification gap before it is a price gap.

A cheaper-looking number on a different size table, a different Incoterm or a missing tray is a different deal. This desk will not recast that gap as a market percentage.

Compound and ASTM or equivalent standard explain many remaining gaps. NBR versus FKM on the same dash size is not a courtesy upgrade. Compression set hours, fuel-swell method and lot files belong on the line. If the specification moves — dash size, Shore A, compound or destination — the line must be re-quoted. Keep the original reply on file so later lots can be compared with the approved item.

Scope differences that usually explain a price gap

Ask which o ring size chart the factory used. Reprint the dash or ID/OD/CS on the invoice description. Do not accept “equivalent” without the millimetre values.

Name the polymer and the ASTM D2000 or equivalent callout. A plant ISO certificate does not replace the compound line. Silicone versus FKM remains a buyer trade-off: wide temperature and biocompatibility versus hydrocarbon resistance at a higher material cost.

Piece price without tray, export carton or freight is incomplete. If the specification moves, re-quote the whole line rather than editing one cell.

What belongs in the comparison pack

AS568 dash table excerpt
Metric ID OD CS sketch
Compound declaration sheet
Packed o-rings in labeled bags

Send the size chart and the quantity you want compared

Attach the chart later by email if needed. This form has no upload field.

Write size standard, compound, hardness and temperature; quantity with unit; destination state or postal code and requested delivery / lead time; required product documents and sample needs. Optional target budget with currency and unit or whole-order basis; optional supplier preference. Drawings can be sent after we reply; this form has no upload field.