joining 1/2" copper to 15mm pipe

Can you use a solder joint? If so, that's probably the easiest - go to any (most...) sheds and you'll find a 1/2" to 15mm coupler.

Almost certainly you'll find 'compression' equivalents too.

 

you can use
1. a 15mm coupling solder, end feed or capillary
2. a comperssion fitting
3. a pushfit,

its the same size +/- a few thousands of an inch,
its the 3/4 to 22mm thats different,

 

Just to be clear, push fit is not allowed on gas pipes. Oil I have never had to do!

 

"...its the 3/4 to 22mm thats different."

Ah, forgot myself there, Mr Plum .

 

Although you can use a 22mm compression fitting, but replace the 22mm olive for the 3/4" end with a 3/4" olive. It will still tighten up in the 22mm comp fitting. ( another one of Tomp's top tips)

 

You've got to love plumbing sizes 1/2" ie 12.5mm = 15mm and 3/4" ie 18mm = 22mm.

 

Not just plumbing sizes Chippie. Doors and man made timber sheet materials also come in "Imperial" sizes (eg doors are usually 78" by 30" and sheet materials are usually 8ft by 4ft.. (but do you know why they're made (usually) in Imperial sizes??) btw I know you can buy metric doors.

 

I know doors and sheet materials are imperial sizes but 8' x 4' x 3/4" is 2440mm x 1220mm x 18mm to the nearest mm, 1/2" isn't 15mm, it's gauged in a different way. I don't know what size they come in Europe.
Saying that though timber lengths are sold in the sawn size in imperial when prepared and in finished size in metric.

 

Main reason thet are made in imperial sizes is the fact that most doors and sheet materials are made for the American/rest of the world market (where things are still measured in Imperial sizes) Our flat has metric doors, Imho, they are far too tall, compared to imperial doors,,,,,,, just don't look right.

 

The only places that seem to use imperial are USA, Burma, Liberia and us sort of.

 

"In the beginning" most houses were built with joists and trusses at 16" centres. 8' x 4' OSB and ply are spot on for this. If you had to use 2.4m x 1.2m, you would have to use more material. At least with modern joists and trusses at 400mm centres you can cut a bit off.