K Type Copper?

[Razor900]

its not an expander Razor the pipe is too big not too small, have only come across it once years ago its Victorian pipe, really thick walled

Depending on the size I’ve expanded 22mm couplings before to go on oversize pipe

 

[ianmcd]

Depending on the size I’ve expanded 22mm couplings before to go on oversize pipe

sorry thought you meant expanding the pipe not the fitting

 

[dilalio]

Expand the new pipe not the old

 

[lostinthelight]

Its ¾ upwards, dont have a vernier guage though so cant get the exact measurement. Going to take a piece away with me to see if we can get something to fit it

Adjustable spanner and tape measure will work as a crude vernier