# Ball Valve Sizes



## dpadden (8/1/11)

I'm sure this will seem like a stupid question to some, but just want to make sure....

I have ordered plenty of 1/2 inch and 1 inch gear from T&S Valves in Sydney in the past. I am looking to buy some more stuff next week and was browsing the web site to see what they have...

Everything now seems to be in mm, so if I am not mistaken the following should apply:

1/2 inch = 15mm
1 Inch = 25mm

??? :unsure:


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## barls (8/1/11)

half inch is 12.5mm mate not 15.


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## dpadden (8/1/11)

barls said:


> half inch is 12.5mm mate not 15.



Thats what I thought, but no such size.... 

http://www.tsvalves.com.au/products.php?cat=56


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## matho (8/1/11)

Hey paddo
The stuff you by a bunnings is all labeled 15mm but it is 1/2 bsp so I think your right about the 15mm but not sure about 25mm 
Just give them a call 

Cheers matho


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## dpadden (8/1/11)

matho said:


> Hey paddo
> The stuff you by a bunnings is all labeled 15mm but it is 1/2 bsp so I think your right about the 15mm but not sure about 25mm
> Just give them a call
> 
> Cheers matho



Thanks Matho, yeah I think I remember seeing that as well at Bunnings. Going to run down there next week so will def. make sure before handing over any hard earned


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## woodwormm (8/1/11)

Paddo said:


> Thanks Matho, yeah I think I remember seeing that as well at Bunnings. Going to run down there next week so will def. make sure before handing over any hard earned




plumbing and valve sizes all work on BSP (British Standard Pipe) (open to corrections on any of this by the way... but i'm confident in my sizing if not my reasons why!)

I think BSP is the measurement of the nominal bore of the pipe, ie not the inner diameter and not the outer diameter but halfway through the wall thickness....

so if you actually measure a 1/2inch BSP thread it is nowhere near half inch it is bigger because it is cut into the outside of the pipe (if male) and the half inch measurement is in the middle of the wall of the pipe.... 

whereas the metric measurements are the actual diameters of the threads.... phew i've just confused myself, not sure if anyone else follows it? 

the conversions...

1/2" BSP = 15mm
3/4" BSP = 20mm
1" BSP = 25mm
1 1/4" BSP = 32mm
1 1/2" BSP = 40mm

hope this helps...


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## michael_aussie (8/1/11)

printed forms section said:


> plumbing and valve sizes all work on BSP (British Standard Pipe) (open to corrections on any of this by the way... but i'm confident in my sizing if not my reasons why!)
> 
> I think BSP is the measurement of the nominal bore of the pipe, ie not the inner diameter and not the outer diameter but halfway through the wall thickness....
> 
> ...


threads that go together are heaven.
mismatched threads are hell.
you need to measure diameters and most important TPI = threads per inch.
1/2"BSP has 14 TPI


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## woodwormm (9/1/11)

michael_aussie said:


> threads that go together are heaven.
> mismatched threads are hell.
> you need to measure diameters and most important TPI = threads per inch.
> 1/2"BSP has 14 TPI



don't get me started on pitches! metric was meant to be easy but we got 3 super common tpi's in metric bolts! 

i always love having a sample with me if i'm not sure, or not at a trusted (educated) supplier.


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## praxis178 (9/1/11)

Just to stir the pot: I'm now starting to see more NPT threaded fittings creeping into the AU market.... Bring a sample if you can it WILL save you work in the end. 

My local vendor of plumbing err brew bling had lots of staff that didn't know there was a difference, till I brought some samples and showed them that there was one!


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## schooey (9/1/11)

I bought my 1/2" SS 3 piece valves from T&S, they were invoiced as 15mm... they are the ones you are after


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## woodwormm (9/1/11)

Thomas J. said:


> Just to stir the pot: I'm now starting to see more NPT threaded fittings creeping into the AU market.... Bring a sample if you can it WILL save you work in the end.
> 
> My local vendor of plumbing err brew bling had lots of staff that didn't know there was a difference, till I brought some samples and showed them that there was one!




AAAAAAAAAAAAHHHHHHHRrrrrrrrrrggggggggggggggggggg F... ing NPT!


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## michael_aussie (10/1/11)

Thomas J. said:


> Bring a sample if you can it WILL save you work in the end.


+1
If you are unsure, take whatever you want to mate with (if you can) to buy its mate.
Even BSPP and BSPT that look similiar won't go together nicely.



it doesn't help when the vendors don't even call something what it actually is.

one of our local hardware stores only stocks imperial bolts, but will point you to them even when you ask for a specific metric size...
"you want M12... well that's 1/2inch" 
not if you want to buy a nut for an existing bolt or vice versa you idiots.


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