You should be able to turn the body of the angle-stop if the nut is held firm with another wrench. if you turn the body and not the nut - It is less likely to damage the copper tube. Depending upon how tight the nut was set - will determine how deformed the copper pipe is. sometimes it is difficult to remove the ferrel.

You have so much oxidation on this valve - I would replace it.
Personally, I never install an appliance onto an old valve.

It looks like you have enough room to cut off the entire angle stop. Use a fine toothed metal blade and cut square - then deburr. A new multi angle stop can then be used with the matching outlets you need. The braided dish washer supply lines come in different configurations. I have found that many of the new dishwashers have a large threaded connector instead of the older 1/4" compression. check yours.

P.S. check inside your pipes for pitting. Often this oxidation can be a result of iron in water which destroys copper pipe.

• 1- NO

• 2- NO

• 3- YES!

Swagelok fittings are different than compression fittings and will not work. Both are very different than flare fittings, which have a tapered nut and require the tubing to be formed in a "flared" taper at the end (using a special tool) and do not use a sleeve (ferrule). They also use a different thread:

You may find that regular compression fittings are labeled "tube" fitting in your locale. Home Depot Canada has them, they include a brass insert (for plastic tubing) and ferrule (for all tubing applications; for your purpose do not use them.

Why don't you take your connectors down to the local mom & pop plumbing / hardware shop instead of going to the "big box", they likely have the part and will be full of good advice as well.

here's the link to the part at HD: 3/8 comp. x 3/4 mip adapter