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WaterTight

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And all metric pipe measurements refer to OD?

So 3.5" cast iron soil will be roughly 3.5" ID and 110mm plastic soil will be something like 105mm ID?

Thanks
 
When I look at a piece of Low Carbon Steel tube, say 1/2" diameter that measurement is the internal diameter. On a copper or plastic 15mm tube the measurement is on the outside diameter. I am not sure if this follows for other pipe materials but at least it does with the ones I am familiar with. I have very rarely worked with cast iron pipe so hopefully someone can tell us if the "rule" works on the larger stuff too.
 
Now you're entering the world of confusion. lol.

It's not that straight forward with cast iron pipe. The internal diameter is around 4" for 4" pipe but it varies a little. There are different pressure classes as there are with steel and that alters the wall thickness a bit so not all 4" will be exactly 4" inside.

If you looked at 4" class C you will see that it is correct on the internal diameter. (4" exactly), after 12", Class B becomes exact on the internal diameter. It changes with size. Have a look at Wikipedia, there is some history and a chart.

Black iron pipe (steel), has different weights too. Red=Heavy, Blue=Medium, Yellow=Light etc.
This effects the bore slightly due to it being thicker walled but not the O.D.

Hope this helps!
 
Last edited:
I don't know, why do they make car tyres in inches diameter and millimetres width?
 
Worked out good thanks kop

111.jpg 222.jpg 333.jpg

New toilet fitted with less of a bodge on the waste. Still had to use a 40mm offset but at least looked neater
 
Offered up a 14 degree angle pan con but ended up too low for soil. Despite angle of cast a 40mm offset and an extension worked fine.

However the last 2 times I've tried to join to cast a multikwik / mcalpine for 4" is too big and a 3.5" is too small. And so I end up squeezing the 4" in but there's no way it's the right size because it always distorts

Multikwik sell connectors for soil that is 88mm-92mm and 99mm-105mm (3.5" and 4" pipe) but in each case what I really needed was one in the middle, like a connector for 92mm-99mm. Doesn't look like such a thing exists...
 
How long did it take cutting the cast ?
 
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