When I first received this set I was very impressed! It glides through slides and 2x4s with ease, and core extraction couldn't be easier. This is an awesome design improvement! However, after drilling 2x4 holes for some lines, the locking bar stopped locking. Neither the pilot hole saw nor the hole saws will snap into place. I don't know if I wore anything or what; But I've only had it for a few months and rarely used it. I'm just replacing the mandrel and hope it holds up.