3/8 inch copper pipe

[toptip123]

I have come across some old imperial copper pipe in my house. The size is 3/8 inch internal diameter. How do I join this to a 15mm?

 

[1john]

try a 10mm reducer

 

[toptip123]

10mm is way too small the outside diamiter is about 13-14 mm

 

[xr4x4]

3/8 is smaller than 10mm i think.

try a plumbers merchants, you might beable to get a 3/8 olive for a 10mm coupler.

just a guess but i know u can do it for 22mm / 3/4 pipe.

 

[1john]

maybe sand it back to get it into a 12mm reducer, it seems strange to be 14mm od as 1/2" pipe will normally squeeze into a 15mm fitting.

 

[toptip123]

i know 1/2 inch pipe will just fit int a 15mm fitting. But it's not 1/2 inch pipe. imperial pipe is mesured on the internal bore. this has a bore of 3/8 inch. It will not fit 10mm or 12mm fittings.

 

[xr4x4]

3/8 = 9.525mm

 

[1john]

This pipe must have some thick walls if it has an id of 3/8" and wont fit a 12mm fitting, I would sand it around to fit in a 12mm fitting it cant be far off.

 

[toptip123]

3/8 = 9.525mm

Yes. your wright. But 3/8 is the internal diameter of the pipe the hole.. outside diameter is about 14 mm.

The pipe fits quite snug inside a 15mm pipe, would it be ok to do this and run some solder round?

 

[1john]

clean up the inside of the pipe and go for it, make sure you are in about 20mm.

 

[mysteryman]

Just for those who are new to this...

Metric copper and plastic pipes are sized on the outside diameter.

Imperial pipes were based upon the bore of the pipe, and the wall thickness added to that makes a greater outside diameter. Thus 1/2 inch copper is just a bit bigger than 15mm copper, and 3/4 inch copper is significantly smaller than 22mm copper.

The same applies to steel pipe. A 1/2 inch bore pipe has an outside diameter and thread size much bigger than half an inch. Fortunately, the world has taken on the Whitworth thread profile as a standard, so fittings are interchangeable.