Post #289491 by Paipo on Sat, Mar 3, 2007 7:39 PM

It's probably the quality of the burrs. I've found anything other than the Hongias seldom run perfectly true in the handpiece and particularly when drilling holes tend to want to skip or kick out. They also tend to feather the stone (if using jade) around the edges of the hole. Make your hole smaller than you need so you've got some room for error, and then widen it out and flatten the bottom with a flat ended cylindrical burr like the one Tama posted 2nd from left.