3/4 OD copper tubing used for water supply - need fitting

[Wilson Churchill]

I am remodeling a kitchen in one of my rentals. I cut one of the water shutoffs for the kitchen sink, because it has a slow leak. I bought both a push fitting and a compression shutoff, but both were just slightly too small for the tubing. The 5/8 od is too small, and the 7/8 is too large. The OD of the copper pipe is 3/4.. It looks like they used refrigeration tubing for the water supply.

I either need a shutoff that will fit directly onto 3/4 OD copper, or a fitting to convert from the 3/4 OD to the standard 5/8 OD for 1/2 copper plumbing. I'd rather not replace the whole service, because I would either have to cut out the floors or dig in the crawlspace to access the plumbing. Any ideas??

[Michael Karl]

@Wilson Churchill, the only difference between refrigeration tubing and plumbing tubing is the way the pipe is listed in sizing, refrigeration tubing is measured in OD and plumbing is measured in ID  so your standard 3/4" plumbing tubing is 7/8" refrigeration tubing.  it is literally the same pipe just listed different.  So what you are saying is 3/4" OD would be a 5/8" plumbing fitting.  you may have to find a local plumbing supply house for a 5/8" shut off.