brake pads and rotors

When ever you have brakes done, they should and need to be done in pairs. ie both back or both front. Now, the need for the rotor to be turned is one you have to think about. Taking it to a shop for that to be done will work but they will measure for the thickness of the rotor and tell you if they can safely turn it. Thinking back about this I have always thought it seemed silly to replace the rotor when it was so close to passing the minimum safety level. BUT, the pressure is great that is applied and the heat is substantial. If in doubt at all, replace the rotor. The new rotor will eliminate the grab-release-grab feeling that occurs when a warped rotor is braking. Often, even a newly turned rotor will still be warped. Now you have mentioned that the metal on metal sound is being heard. This is a serious state and I am thinking that you might be in replacement mode already. Good luck with the brakes. DONE IN PAIRS. ALWAYS.......