Hey
My TP has been suffering from a metal on metal grinding noise under heavy braking. At first it seemed like this was being cause because the brake pads had worn down and were scoring the disc, but after checking the pads they still have plenty of pad material left on them but the discs were scored badly ( I guess they weren't machined last time the pads were changed). Would scored discs result in an awful grinding sound? Even thou the pads are still in good condition?

Are the pads glazed over?

Yes, if the rotors are scored then they're more than likely glazed as well. How deep is the scoring?

maybe you had a few small stones in there that made the groves but after using the brakes a few times they might have freed them self.
Sounds like time for a machineing or buy a new set for like $115 of ebay like i did a year ago. puls your pad might be moving to much thus allowing small rock to get in. there's a spray u can get to spray on the back of the pad between the metal shim (don't know name) so that the back of the pad sticks to the metel shim better thus making it move around less. sorry can't remember the name of the spray but most auto place will have something similar.

it could just be that the pads are an extremely hard compound, or there is some sort of movement in the pad in the caliper.