A picture would be helpful, but I will try to answer your question based on what I think you are trying to do. Twisting/spinning the copper supply lines is going to result in damage to your pipes and a leak.
You need two crescent, or two open end wrenches, one to hold the copper pipe from twisting, and a second to tighten the supply line hose. Don't make it too tight or too loose. I would guess about 10 foot lbs. I would use some teflon tape or Rectorseal Tplus2 on the threaded connections to ensure a watertight fit, which you can get at your local hardware store.
Date published: 2018-01-06