Originally posted by Silversvt:
So let's set this straight:
- This is a one piece rotor
- The cross-drilling / dimples don't have the hairline cracks I was expecting to see.. good sign
- The rotor failed at the hat, I've never seen drilling there.. ever.. is that to lighten it up??
It seems to me that the place where the hat "mates" to the actual rotor is where most of the torsional load would be applied.. the worst place to drill hole IMO. 
I'm still glad mine are only slotted. I see way to many cross-drilled rotors with hairline cracks all around the holes.
Porsche and Mercedes OEM that on their cars but the hole are cast in. Even BAER drills the holes after the rotors have been machined..The Porsche and Mercedes rotors are ceramic not steel.
You are right about drilling holes in the hat area of the rotors, it takes a real dipstick to do something that stupid! Cross drilling or slotting the rotors on street cars is useless, it only looks cool.
