[clf]

The chamfering is a design feature. I have read about this, but cannot remember what it is for exactly. Something like reduction of noise, or a smoother application. If I recall, it is something like due to the rotation of the disc, as the pad is applied, it does not get applied perpendicular to the disc on its initial contact (imagine your shoe when walking, the toe touches the ground first, and the rotates along the sole to the heel). I recall it making sense at the time when I read of it though.