I purchased this kit several months ago, based on the excellent customer reviews.  The reason for the purchase was (and is) I had several expensive speciality interior doors to install and I wanted to get things right the first time.  This is versus my normal practice of having to do many things twice.  I installed the kit per the instructions, started boring and within 3 minutes (or less) the bore bit sheared at the connection to the chank.  I did not torque it and the pressure was moderate to light.  Based on the others feedback, I suspect mine had a manufacturing flaw (not to sweet on a 300$ item).  Now I get to waste my time trying to return it or get a replacement bit.  Needless to say, I am disappointed hence my 1 star ....