Any ideas where to buy mm measured tube in the US? I need 15mm not 1/2".
Since 15mm is an external "pipe" measurement and 1/2" is an internal "tube" measurement, how far off 15mm is the 1/2" external measurement?
"15mm is an external "pipe" measurement and 1/2" is an internal "tube"
If this is true, the OD of the 15mm is smaller than the ID of 1/2" pipe. According to my brief search, 3/8 pipe could be turned in a lathe to match 15mm. If just one end needs to be 15mm, that could solve the problem. Brass pipe solders easily if that will help.
If the OP is going by convention:
then 1/2" copper tubing would be 5/8" outer diameter
that converts to 12.7mm inner dia and 15.875mm outer dia
While it may not pass inspection on a rocket engine or get passed on a building permit for plumbing, it and the standard connecting bits do sound "sorta close enough".
Close only counts in horseshoes. In plumbing, with water under pressure, it's a sure recipe for a leak. Jury rigged half asseries have a good chance of not being covered by your homeowners insurance when they fail. Trying to hook up BSP to standard American plumbing requires the correct adapters. You were given a source for adapters, plus the manufacturer sells a kit to do it. I'd suggest you going one or the other route rather than striking out boldly where no one has gone before. It's for a reason.