I don't think anyone said it will come apart, just that it could come apart, and at a very high speed. I think people are just saying they would rather be safe than save a buck. I also worry about the vibration issue.Both of you have made very nice extensions. The solid piece one does look more of a finished item, the tightening slot is a very nice feature. But getting back to Matt’s design if you guys think for one minute it’s going to come apart from centrifugal force then you’re just nit picking his design. I could put that collar in my lathe and spin it a whole lot faster than the rotary could ever go and it won’t come apart. Also there is no way that a rotary will ever develop enough torque to break the bolt or collar.