Cartridge Sizes

Does anyone know how cartridge diameters are determined?
I measured the diameter of my cartridge with calipers, it was .730 diameter so I ordered a 3/4" cartridge...well the 3/4 cartridge measures .938 diameter!

Aha! Maybe they use pipe sizes, nope 1/2 pipe is .840 dia and 3/4 is 1.050.

Can anyone explain this?

Thanks

cartridges for what? A Gun.

You have a particular make and model of something you need parts for?

Mr_David said:

cartridges for what? A Gun.

You have a particular make and model of something you need parts for?

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A cartridge for a bathroom sink faucet. The particular brand is Sigma. I finlly got the right size cartridge after three attempts but the sizing doesn't make sense.

Not familiar with sigma but I am going to take a look.

That's why you don't order cartridges by size. You order it by the the correct brand, model and part number. Taking measurements just makes it a million times more difficult and you end up in the situation your in. If you don't have the information than someone could identify for you (which would have only took one time to get the correct one)

LockePlumbing said:

That's why you don't order cartridges by size. You order it by the the correct brand, model and part number. Taking measurements just makes it a million times more difficult and you end up in the situation your in. If you don't have the information than someone could identify for you (which would have only took one time to get the correct one)

Click to expand...

Had I known at the time, I certainly would have ordered by make & model number but there was no markings either on the faucet or the cartridge so my only option was to try and match it up by size.
But thank you for pointing out the obvious.
It still doesn't answer my original question why a cartridge that measures .730 in diameter would be considered a 1/2" cartridge and why one that measures .938 would be considered a 3/4" cartridge.

George_Hicks said:

Can anyone explain this?

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I know that I'm responding to a 7 year old thread.

Odds are that 1/2" and 3/4" refer to the nominal sizes of the pipes that are either feeding the valve, or coming off of it.

They are not the size of the part itself, they indicate the nominal valve size that the part fits into.

- Eric