Omniswivel High Flow QD O-Ring size

[HandsomeYoungPete]

Hey there knowledge base, I'm trying to work out the size of the o-rings in the omniswivel high flow QD female connector, the small one looks like an AS568 012 measuring CS 1.78 and ID 9.25, the larger one is also CS 1.78 but has an ID of 9.45 which doesn't come up on any chart I can find

 

[Tanks A Lot]

The only standard O-ring that comes close to your measurements (1.78mm x 9.45mm) is a ISO3601-A0095 at 1.80mm x 9.50mm. The same O-ring can be found under the DIN3771 (9.5 x 18) or JISB2401 (1.80 x 9.50 - A & G) standard.

BS1806 O-rings are likely not it. The only ones "close" to your measurements are:

• BS1806-611 = 1.78mm x 8.74mm
• BS1806-012 = 1.78mm x 9.25mm
• BS1806-905 = 1.83mm x 10.52mm

Neither of these seem a good fit. I'd suggest you do the measurements again, possibly with the below method. It generally yields great results:

1. Take a piece of plain paper and roll it into a cylinder. The cylinder should have a diameter very close to what you expect your inner diameter of the O-ring to be. Make sure that the ends of the paper cylinder slightly overlap.

2. Take this paper cylinder and insert it into your O-ring, then unroll your paper cylinder until it sits nice and tight against your O-ring. Now make a small mark across where your paper cylinder overlaps with itself.

3. All that is left to do is unroll your cylinder, measure the distance with a quality engineer’s ruler or calliper, and divide this length by π. This results in a great approximation for the inner diameter of the O-ring you have at hand.

In the above example, we got to divide 78.94mm by π, which gives us 25.13mm. This is remarkably close to what this O-ring should be. It is a BS1806-022, which measures 25.12 mm across the inner diameter. The larger and softer the O-ring, the worse the results with this method usually become.

I find measuring O-ring diameters directly with a calliper all but impossible, except for really small ones. There is always some inherent stretch one introduces when fiddling around with the calliper.

 

[HandsomeYoungPete]

Thanks Tanks A Lot, you could not have explained that any better. Great technique for measuring ID.

So now we have an ID of 9.13mm for the small one and an ID of 9.85mm for the large one

 

[happy-diver]

So are you going to roll those sizes from dough

https://www.allorings.com/Metric-O-Ring-Size-Chart

Let's hope you didn't have to roll some paper to measure those, the other guy could do with eye glasses

Is it not exciting, when you set up your orings on some clean white printing paper, before you chop it up

 

[Tanks A Lot]

[...]So now we have an ID of 9.13mm for the small one and an ID of 9.85mm for the large one

If you are sure about the 1.78mm CS, then these are the O-rings that come closest:

For the 9.13mm

Cross Section (mm)	Inner Diameter (mm)	U.S. (AS568)	British (BS1806)	ISO3601	German (DIN3771)	French (NFT47-501)	U.S. (JISB2401)	Parker	Italian (UNI)
1.78	9.25	012	012	012				2-012	2037
1.80	9.00			A0090	9.00 x 1.80	A0090	1.80 x 9.00 - A & G

For the 9.85mm

Cross Section (mm)	Inner Diameter (mm)	ISO3601	German (DIN3771)	French (NFT47-501)	U.S. (JISB2401)	Parker
1.78	9.75					5-211
1.80	9.75				1.80 x 9.75 - G
1.80	10.00	A0100	10.00 x 1.80	A0100	1.80 x 10.00 - A & G
1.90	9.80				P10

 

[HandsomeYoungPete]

So are you going to roll those sizes from dough

https://www.allorings.com/Metric-O-Ring-Size-Chart

Let's hope you didn't have to roll some paper to measure those, the other guy could do with eye glasses

Is it not exciting, when you set up your orings on some clean white printing paper, before you chop it up

Thanks for the wise words Bloke, Kraft cheese slices pressed through a tea strainer produce a comical outcome, unlike herb crusted croutons in a blender.

Been on that website, Omniswivel, being made in the land that is soon to be great again, is not likely to be using anything metric, or are they....

I can usually cross reference the sizes but I'm struggling with this one, hence the question, was hoping for an Omniswivel specific response.

 

[happy-diver]

As easy as going into the site and pressing the land that is soon to be great again button dude